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Kugadzirwa kweElectrosynthesis yeadipic acid (inotangira nylon 66) kubva muoiri yeCA (musanganiswa wecyclohexanone necyclohexanol) inzira inogara kwenguva refu inogona kutsiva nzira dzechinyakare dzinoda mamiriro akaoma. Zvisinei, kuwanda kwemagetsi mashoma uye kukwikwidzana kwekushanduka kweokisijeni kunodzikamisa zvakanyanya mashandisirwo ayo mumaindasitiri. Mubasa iri, tinogadzirisa nickel double hydroxide nevanadium kuti tiwedzere kuwanda kwemagetsi uye kuchengetedza kushanda kwefaradaic kwakanyanya (>80%) pamusoro penzvimbo yakakura yekugona (1.5–1.9 V vs. reversible hydrogen electrode). Zvidzidzo zvekuedza uye zvedzidziso zvakaratidza mabasa maviri akakosha ekuchinja kweV, kusanganisira kukurumidza kuvakazve catalyst uye kuvandudzwa kwe cyclohexanone adsorption. Sehumbowo hwepfungwa iyi, takagadzira membrane-electrode assembly yakagadzira adipic acid ine kushanda kwefaradaic kwakanyanya (82%) uye kubereka (1536 μmol cm-2 h-1) pakushanda kwemagetsi kwakakodzera mumaindasitiri (300 mA cm-2), uku tichiwana kugadzikana >50 maawa. Basa iri rinoratidza kuti chinhu chinobatsira zvikuru pakugadzirwa kwe adipic acid nema electrosynthesis ane simba guru uye anogona kushandiswa mumaindasitiri.
Adipic acid (AA) ndeimwe yeanonyanya kukosha e aliphatic dicarboxylic acids uye inonyanya kushandiswa mukugadzira nylon 66 nedzimwe polyamides kana polymers1. Muindasitiri, AA inogadzirwa nekusanganisa musanganiswa we cyclohexanol ne cyclohexanone (kureva, mafuta eAA) uchishandisa 50–60 vol% nitric acid se oxidizing agent. Maitiro aya ane hanya nezvakatipoteredza zvine chekuita nekubuda kwe nitric acid yakawanda uye nitrogen oxides (N2O neNOx) semagasi egreenhouse2,3. Kunyangwe H2O2 ichigona kushandiswa seimwe nzira ye green oxidizing agent, mutengo wayo wakakwira uye mamiriro ekugadzira akaomarara anoita kuti zviome kushandiswa, uye nzira inoshanda uye inogara kwenguva refu inodiwa4,5,6.
Mumakore gumi apfuura, nzira dzekugadzira makemikari nemafuta emagetsi dzakakwezva kutariswa kuri kuwedzera kubva kumasayendisiti nekuda kwekubatsira kwadzo kushandisa simba rinogona kushandiswazve uye kushanda mumamiriro ezvinhu asina kusimba (semuenzaniso, tembiricha yemukamuri uye kumanikidzwa kwemhepo)7,8,9,10. Panyaya iyi, kuvandudzwa kwekushandurwa kwemafuta eKA kuita AA nemagetsi kwakakosha kuti uwane zvakanakira zviri pamusoro apa pamwe nekubvisa kushandiswa kwe nitric acid ne nitrous oxide emissions zvinowanikwa mukugadzirwa kwakajairika (Mufananidzo 1a). Basa rekutanga rakaitwa naPetrosyan et al., avo vakataura kuti electrocatalytic oxidation reaction ye cyclohexanone (COR; cyclohexanone kana cyclohexanol zvave zvichidzidzwa kakawanda sezvinomiririra mafuta eKA) pa nickel oxyhydroxide (NiOOH), asi low current density (6 mA cm-2) uye mwero weAA yield (52%) zvakawanikwa11,12. Kubva ipapo, kufambira mberi kukuru kwakaitwa mukugadzirwa kwe nickel-based catalysts yekusimudzira COR activity. Semuenzaniso, catalyst ine nickel hydroxide (Cu-Ni(OH)2) yakagadzirwa nemhangura kuti isimudzire kupatsanuka kweCα-Cβ mucyclohexanol13. Munguva pfupi yapfuura takashuma nezve catalyst yeNi(OH)2 yakagadziriswa nesodium dodecyl sulfonate (SDS) kuti igadzire hydrophobic microenvironment inopfumisa cyclohexanone14.
a Matambudziko ekugadzirwa kweAA neelectrooxidation yemafuta eKA. b Kuenzaniswa kwe electrocatalytic COR yema catalysts akambotaurwa nezvawo eNi-based uye catalyst yedu mu system ye three-electrode uye flow battery system11,13,14,16,26. Ruzivo rwakadzama nezve reaction parameters uye reaction performance rwuri mu Supplementary Tables 1 ne 2. c Catalytic performance yema catalysts edu eNiV-LDH-NS eCOR mu H-cell reactor neMEA, ayo anoshanda munzvimbo dzakasiyana-siyana.
Kunyangwe nzira dziri pamusoro dzakavandudza basa reCOR, ma catalysts anotsanangurwa eNi-based akaratidza kushanda kwepamusoro kweAA Faraday (FE) (>80%) chete pamasimba akaderera, kazhinji ari pasi pe1.6 V zvichienzaniswa nehydrogen electrode inodzoserwa (RHE, yakapfupikiswa VRHE). Saka, huwandu hwemagetsi hunotaurwa (kureva, huwandu hwemagetsi hwakawedzerwa neFE) hweAA hunogara huri pasi pe60 mA cm−2 (Mufananidzo 1b neTafura Yekuwedzera 1). Hunhu hwemagetsi hwakaderera huri pasi pezvinodiwa zveindasitiri (>200 mA cm−2)15, izvo zvinokanganisa zvakanyanya tekinoroji yemagetsi yekugadzirwa kweAA yakakwira (Mufananidzo 1a; pamusoro). Kuti uwedzere huwandu hwemagetsi, hunogona kushandiswa mukana wakanaka (wemagetsi matatu) kana voltage yakakwira yemasero (yemagetsi maviri) inova nzira iri nyore yekuchinja kwemagetsi akawanda, kunyanya oxygen evolution reaction (OER). Zvisinei, kuCOR ine anodic potentials yakakwira, OER inogona kuva makwikwi makuru mukuderedza FE yeAA, nokudaro ichideredza kushanda zvakanaka kwesimba (Mufananidzo 1a; pasi). Semuenzaniso, tichiongorora kufambira mberi kwapfuura (Mufananidzo 1b neSupplementary Table 1), takaodzwa mwoyo kuona kuti FE yeAA paSDS-modified Ni(OH)2 yakaderera kubva pa93% kusvika pa76% nekuwedzera simba rinoshandiswa kubva pa1.5 VRHE kusvika pa1.7 VRHE14, nepo FE yeAA paCuxNi1-x(OH)2/CF yakaderera kubva pa93% kusvika pa69% nekuwedzera simba kubva pa1.52 VRHE kusvika pa1.62 VRHE16. Saka, chikamu cheAA chakataurwa hachiwedzere zvakaenzana pamasimba akakwira, izvo zvinoderedza zvakanyanya kuvandudzwa kweAA performance, tisingatauri nezvekushandiswa kwesimba kwakawanda nekuda kweFE yakaderera yeAA. Pamusoro pema catalysts akavakirwa pa nickel, ma catalysts akavakirwa pa cobalt akaratidzawo basa re catalytic mu COR17,18,19. Zvisinei, kushanda kwawo kunoderera pa potentials dzakakwirira, uye zvichienzaniswa nema catalysts akavakirwa pa Ni, ane mikana yakawanda yekusashanda mumaindasitiri, akadai sekuchinja-chinja kwemitengo uye zvinhu zvidiki. Nokudaro, zvinokurudzirwa kugadzira ma catalysts akavakirwa pa Ni ane current density yakakwira uye FE mu COR kuti zviite kuti zvishande kuwana goho repamusoro reAA.
Mubasa iri, tinoshuma vanadium(V)-modified nickel layered double hydroxide nanosheets (NiV-LDH-NS) sema electrocatalysts anoshanda ekugadzira AA kuburikidza neCOR, ayo anoshanda pamusoro pehuwandu hwakawanda hwesimba rine OER yakadzvinyirirwa zvakanyanya, achiwana FE yakakwira uye huwandu hwazvino mumasero ese eH uye membrane electrode assemblies (MEAs; Mufananidzo 1 b). Tinotanga taratidza kuti kushanda kweacetylene oxidation pamusoro peNi(OH)2 nanosheet catalyst yakajairika (Ni(OH)2-NS) inoderera, sezvaitarisirwa, pahuwandu hwakawanda, kubva pa80% pa1.5 VRHE kusvika pa42% pa1.9 VRHE. Kusiyana zvakanyanya, mushure mekugadzirisa Ni(OH)2 neV, NiV-LDH-NS yakaratidza huwandu hwakawanda hwesimba pahuwandu hwakapihwa uye, chinonyanya kukosha, yakachengetedza FE yakakwira pamusoro pehuwandu hwakawanda hwesimba. Semuenzaniso, pa1.9 VRHE, yakaratidza huwandu hwemagetsi hwe170 mA cm−2 uye FE ye83%, inova catalyst yakanaka yeCOR mu three-electrode system (Mufananidzo 1c uye Supplementary Table 1). Data rekuyedza uye redzidziso rinoratidza kuti V modification inokurudzira reduction kinetics kubva kuNi(OH)2 kuenda ku high-valent Ni oxyhydroxides (Ni3+xOOH1-x), iyo inoshanda sechikamu chinoshanda cheCOR. Uyezve, V modification yakasimudzira adsorption ye cyclohexanone pamusoro pe catalyst, iyo yakaita basa guru mukudzvinyirira OER pa high anodic potentials. Kuti tiratidze kugona kweNiV-LDH-NS mune imwe mamiriro ezvinhu aripo, takagadzira MEA flow reactor uye takaratidza FE yeAA (82%) pahuwandu hwemagetsi hunoenderana neindasitiri (300 mA cm−2), iyo yakakwira zvakanyanya kupfuura zvatakawana kare mu membrane flow reactor (Mufananidzo 1b uye Supplementary Table 2). Mugove wakafanana weAA (1536 μmol cm−2 h−1) waive wakanyanya kupfuura wakawanikwa uchishandisa thermal catalytic process (<30 mmol gcatalyst−1 h−1)4. Uyezve, catalyst yakaratidza kugadzikana kwakanaka pakushandisa MEA, ichichengetedza FE >80% AA kwemaawa makumi matanhatu pa200 mA cm−2 uye FE >70% AA kwemaawa makumi mashanu nemasere pa300 mA cm−2. Pakupedzisira, chidzidzo chekutanga chekufungidzira (FEA) chakaratidza kushanda zvakanaka kwehurongwa hwemagetsi hwekugadzira AA.
Zvichienderana nemabhuku apfuura, Ni(OH)2 chinhu chinowanzo shandiswa pakugadzira zvinhu chinoratidza kushanda kwakanaka kweCOR, saka Ni(OH)2-NS13,14 yakagadzirwa kekutanga kuburikidza nenzira ye coprecipitation. Samples dzakaratidza chimiro cheβ-Ni(OH)2, icho chakasimbiswa ne X-ray diffraction (XRD; Fig. 2a), uye ma nanosheets akatetepa zvakanyanya (ukobvu: 2–3 nm, saizi ye lateral: 20–50 nm) akaonekwa ne high-resolution transmission electron microscopy (HRTEM; Supplementary Fig. 1) uye atomic force microscopy (AFM) measurements (Supplementary Fig. 2). Kuunganidzwa kwema nanosheets kwakaonekwawo nekuda kwehunhu hwavo hwakatetepa zvakanyanya.
Mapatani eX-ray eDiffraction eNi(OH)2-NS neNiV-LDH-NS. FE, throughput, uye AA current density pa b Ni(OH)2-NS uye c NiV-LDH-NS pamatanho akasiyana. Error bars dzinomiririra standard deviation yezvikamu zvitatu zvakazvimiririra uchishandisa catalyst imwechete. d HRTEM image yeNV-LDH-NS. Scale bar: 20 nm. HAADF-STEM image yeNiV-LDH-NS uye elemental mep inoenderana inoratidza kugoverwa kweNi (green), V (yero), uye O (bhuruu). Scale bar: 100 nm. fNi 2p3/2, gO 1 s, uye h V 2p3/2 XPS data yeNi(OH)2-NS (kumusoro) neNiV-LDH-NS (pasi). i FE na j ndiwo mashandiro eAA pama catalysts maviri pamusoro pe7 cycles. Error bars dzinomiririra standard deviation yezvikamu zvitatu zvakazvimiririra uchishandisa catalyst imwechete uye dziri mukati me10%. Ruzivo rusina kujeka rwe a–c na f–j rwunowanikwa mumafaira eruzivo asina kujeka.
Takazoongorora mhedzisiro yeNi(OH)2-NS paCOR. Tichishandisa constant potential electrolysis, takawana 80% FE yeAA pa low potential (1.5 VRHE) pasina OER (Mufananidzo 2b), zvichiratidza kuti COR ine simba rakawanda kupfuura OER pa low anodic potentials. Chinhu chikuru chakawanikwa chiri glutaric acid (GA) ine FE ye3%. Kuvapo kwetrace amounts ye succinic acid (SA), malonic acid (MA), uye oxalic acid (OA) kwakayerwawo neHPLC (ona Supplementary Picture 3 ye product distribution). Hapana formic acid yakawanikwa muchigadzirwa, zvichiratidza kuti carbonate inogona kuumbwa seC1 by-product. Kuti tiedze iyi hypothesis, electrolyte kubva ku complete electrolysis ye 0.4 M cyclohexanone yakagadziriswa uye gaseous products dzakapfuudzwa kuburikidza neCa(OH)2 solution. Nekuda kweizvozvo, mhinduro yakava turbid, zvichisimbisa kuumbwa kwecarbonate mushure me electrolysis. Zvisinei, nekuda kwemagetsi mashoma anowanikwa panguva yekushandiswa kwemagetsi (Mufananidzo 2b, c), huwandu hwecarbonate hwakaderera uye hwakaoma kuyera. Pamusoro pezvo, zvimwe zvigadzirwa zveC2-C5 zvinogonawo kuumbwa, asi huwandu hwazvo hahugone kuyera. Kunyangwe huwandu hwezvigadzirwa hwakaoma kuyera, 90% yehuwandu hwemagetsi emagetsi hunoratidza kuti maitiro mazhinji emagetsi akaonekwa, izvo zvinopa hwaro hwekunzwisisa kwedu mashandiro. Nekuda kwehuwandu hwemagetsi hwakaderera (20 mA cm−2), goho reAA raive 97 μmol cm−2 h−1 (Mufananidzo 2b), rakaenzana ne19 mmol h−1 g−1 zvichibva pakuwanda kwe catalyst (5 mg cm−2), iyo yakaderera pane thermal catalytic productivity (~30 mmol h−1 g−1)1. Kana simba rinoshandiswa rakawedzera kubva pa1.5 kusvika pa1.9 VRHE, kunyangwe huwandu hwemagetsi hwakawedzera (kubva pa20 kusvika 114 mA cm−2), panguva imwe chete pakava nekuderera kukuru muAA FE, kubva pa80% kusvika pa42%. Kudzikira kweFE pamasimba akanaka kunonyanya kukonzerwa nemakwikwi eOER. Kunyanya pa1.7 VRHE, makwikwi eOER anotungamira kudzikira kukuru muAA FE, nokudaro zvichideredza zvishoma mashandiro eAA nekuwedzera kwehuwandu hwemagetsi. Saka, kunyangwe huwandu hwemagetsi hushoma hweAA hwakawedzera kubva pa16 kusvika 48 mA cm−2 uye kugadzirwa kweAA kwakawedzera (kubva pa97 kusvika 298 μmol cm−2 h−1), simba rakawanda rakashandiswa (2.5 W h gAA−1 yakawanda kubva pa1.5 kusvika pa1.9 VRHE), zvichikonzera kuwedzera kwemhepo inoburitsa kabhoni ye2.7 g CO2 gAA−1 (ruzivo rwekuverenga rwunopihwa muSupplementary Note 1). OER yakambotaurwa kare semukwikwidzi weCOR reaction pa high anodic potentials inoenderana nemishumo yapfuura uye inomiririra dambudziko guru rekuvandudza kugadzirwa kweAA14,17.
Kuti tigadzire COR catalyst inoshanda zvakanyanya yeNi(OH)2-NS, takatanga taongorora active phase. Takaona peaks pa473 cm-1 uye 553 cm-1 mumhedzisiro yedu ye in situ Raman spectroscopy (Supplementary Fig. 4), inoenderana nekukotama nekutambanudza kweNi3+-O bonds muNiOOH, zvichiteerana. Zvakanyorwa kuti NiOOH imhedzisiro yekudzikiswa kweNi(OH)2 uye kuunganidzwa kweNi(OH)O paanodic potentials, uye chaizvoizvo ndiyo active phase mu electrocatalytic oxidation20,21. Saka, tinotarisira kuti kukurumidzisa process yekuvakazve phase yeNi(OH)2 kuenda kuNiOOH kunogona kuwedzera catalytic activity yeCOR.
Takaedza kugadzirisa Ni(OH)2 nesimbi dzakasiyana sezvo zvakaonekwa kuti heteroatom modification inokurudzira kugadziriswa kwechikamu mu transition metal oxides/hydroxides22,23,24. Samples dzakagadzirwa ne co-deposition yeNi uye yechipiri metal precursor. Pakati pemhando dzakasiyana dzesamples dzakagadziriswa nesimbi, V-modified sample (V:Ni atomic ratio 1:8) (inonzi NiV-LDH-NS) yakaratidza high current density muCOR (Supplementary Fig. 5) uye chinonyanya kukosha, high AA FE pamusoro pe wide potential window. Kunyanya, pa low potential (1.5 VRHE), current density yeNiV-LDH-NS yaive yakakwira ka1.9 pane yeNi(OH)2-NS (39 vs. 20 mA cm−2), uye AA FE yaive yakafanana pane ese ari maviri catalysts (83% vs. 80%). Nekuda kwehuwandu hwemagetsi hwakakwira uye FE AA yakafanana, kubereka kweNiV-LDH-NS kwakakwira ka2.1 kupfuura kweNi(OH)2-NS (204 vs. 97 μmol cm−2 h−1), zvichiratidza mhedzisiro yekusimudzira kwekuchinja kweV pahuwandu hwemagetsi pamasimba akaderera (Mufananidzo 2c).
Nekuwedzera kwesimba rinoshandiswa (semuenzaniso, 1.9 VRHE), huwandu huripo paNiV-LDH-NS hwakakwira ka1.5 pane hweNi(OH)2-NS (170 vs. 114 mA cm−2), uye kuwedzera kwacho kwakafanana nekwepasimba rakaderera (ka1.9 kakawanda). Zvinonyanya kukosha, NiV-LDH-NS yakaramba iine AA FE yakakwira (83%) uye OER yakaderedzwa zvakanyanya (O2 FE 4%; Mufananidzo 2c), ichipfuura Ni(OH)2-NS uye yakambotaurwa nezvayo nemacatalysts ane AA FE yakaderera zvikuru pasimba rakakwirira reanodic (Supplementary Table 1). Nekuda kwehuwandu hweAA hwakakwira muhuwandu hweAA (1.5–1.9 VRHE), huwandu hweAA hwe867 μmol cm−2 h−1 (hwakaenzana ne174.3 mmol g−1 h−1) hwakawanikwa pa1.9 VRHE, zvichiratidza kushanda zvakanaka mumasystem e electrocatalytic uye even thermocatalytic apo chiitiko chacho chakagadziriswa nehukuru hwese hweNiV-LDH-NS samples (Supplementary Fig. 6).
Kuti tinzwisise huwandu hwemagetsi akawandisa uye FE yakakwira pamusoro pehuwandu hwakakura hwesimba mushure mekushandura Ni(OH)2 neV, takatsanangura chimiro cheNiV-LDH-NS. Mhedzisiro yeXRD yakaratidza kuti shanduko neV yakakonzera shanduko yechikamu kubva kuβ-Ni(OH)2 kuenda kuα-Ni(OH)2, uye hapana mhando dzekristalline dzine chekuita neV dzakaonekwa (Mufananidzo 2a). Mhedzisiro yeHRTEM inoratidza kuti NiV-LDH-NS inogara nhaka morphology ye ultrathin Ni(OH)2-NS nanosheets uye ine mativi akafanana (Mufananidzo 2d). Kuyerwa kweAFM kwakaratidza mafambiro akasimba ekuunganidza ma nanosheets, zvichikonzera ukobvu hunoyerwa hweinenge 7 nm (Mufananidzo Wekuwedzera 7), iyo yakakura kupfuura iyo yeNi(OH)2-NS (ukobvu: 2–3 nm). Kuongororwa kweEnergy-dispersive X-ray spectroscopy (EDS) mapping (Mufananidzo 2e) kwakaratidza kuti zvinhu zveV neNi zvakapararira zvakanaka muma nanosheets. Kuti tinzwisise chimiro chemagetsi cheV uye mhedzisiro yayo paNi, takashandisa X-ray photoelectron spectroscopy (XPS) (Mufananidzo 2f–h). Ni(OH)2-NS yakaratidza hunhu hwe spin-orbit peaks dzeNi2+ (hunhu hwechikadzi pa855.6 eV, satellite peak pa861.1 eV, Mufananidzo 2f)25. O1 s XPS spectrum yeNi(OH)2-NS inogona kukamurwa kuita peaks nhatu, pakati padzo peaks dziri pa529.9, 530.9 uye 532.8 eV dzinonzi dzinobva ku lattice oxygen (OL), hydroxyl group (Ni-OH) uye oxygen absorbed on surface defects (OAds), zvichiteerana (Mufananidzo 2g)26,27,28,29. Mushure mekushandurwa neV, V 2p3/2 peak yakaonekwa, iyo inogona kupatsanurwa kuita misoro mitatu iri pa517.1 eV (V5+), 516.6 eV (V4+) uye 515.8 eV (V3+), zvichiteerana, zvichiratidza kuti mhando dzeV dziri muchimiro dziripo zvakanyanya mumamiriro ekupisa kwakanyanya (Mufananidzo 2h)25,30,31. Pamusoro pezvo, Ni 2p peak pa855.4 eV muNiV-LDH-NS yakachinjwa zvisina kunaka (neinenge 0.2 eV) zvichienzaniswa neiyo iri muNi(OH)2-NS, zvichiratidza kuti maerekitironi akatamiswa kubva kuV kuenda kuNi. Mamiriro eNi akaderera eNi akaonekwa mushure mekushandurwa kweV aienderana nemhedzisiro yeNi K-edge X-ray absorption near-edge spectroscopy (XANES) (ona chikamu che "V Modification Promotes Catalyst Reduction" pazasi kuti uwane rumwe ruzivo). Iyo NiV-LDH-NS mushure mekurapwa kweCOR kweawa imwe chete yakasarudzwa seNiV-LDH-POST uye yakanyatsotsanangurwa uchishandisa transmission electron microscopy, EDS mapping, X-ray diffraction, Raman spectroscopy, uye XPS measurements (Supplementary Figs. 8 na 9). Ma catalysts akaramba ari aggregates ane ultrathin nanosheet morphology (Supplementary Fig. 8a–c). Crystallinity yemasamples yakaderera uye V content yakaderera nekuda kweV leaching uye catalyst reconstruction (Supplementary Fig. 8d–f). XPS spectra yakaratidza kudzikira kweV peak intensity (Supplementary Fig. 9), iyo yakakonzerwa neV leaching. Pamusoro pezvo, O1s spectrum analysis (Supplementary Fig. 9d) uye kuyerwa kweelectron paramagnetic resonance (EPR) (Supplementary Fig. 10) zvakaratidza kuti huwandu hwemhepo isina kuchena paNiV-LDH-NS hwakawedzera mushure meawa imwe chete ye electrolysis, izvo zvinogona kukonzera kuchinja kusina kunaka musimba rekubatanidza Ni 2p (ona Supplementary Figs. 9 ne10 kuti uwane rumwe ruzivo)26,27,32,33. Saka, NiV-LDH-NS yakaratidza shanduko shoma yechimiro mushure meawa imwe chete yeCOR.
Kuti tisimbise basa rakakosha reV mukusimudzira COR, takagadzira maNiV-LDH catalysts ane maV:Ni atomic ratios akasiyana (1:32, 1:16, uye 1:4, akanyorwa seNiV-32, NiV-16, uye NiV-4, zvichiteerana) kunze kwe1:8 nenzira imwecheteyo ye coprecipitation. Mhedzisiro yeEDS mapping inoratidza kuti V:Ni atomic ratio iri mu catalyst iri pedyo neiyo ye precursor (Supplementary Fig. 11a–e). Nekuwedzera kweV modification, simba reV 2p spectrum rinowedzera, uye simba rekubatanidza reNi 2p region rinoramba richichinja kuenda ku negative side (Supplementary Fig. 12). Panguva imwe chete, chikamu cheOL chakawedzera zvishoma nezvishoma. Mhedzisiro ye catalytic test inoratidza kuti OER inogona kudzvinyirirwa zvinobudirira kunyangwe mushure mekushandurwa kudiki kweV (V:Ni atomic ratio ye1:32), neO2 FE ichidzikira kubva pa27% kusvika 11% pa1.8 VRHE mushure mekushandurwa kweV (Supplementary Fig. 11f). Nekuwedzera kwechiyero cheV:Ni kubva pa1:32 kusvika 1:8, catalytic activity yakawedzera. Zvisinei, nekuwedzera kwekushandurwa kweV (V:Ni ratio ye1:4), huwandu hwezvino hunoderera, izvo zvatinofungidzira kuti zvinokonzerwa nekudzikira kwehuwandu hweNi active sites (kunyanya NiOOH active phase; Supplementary Fig. 11f). Nekuda kwekusimudzira mhedzisiro yekushandurwa kweV uye kuchengetedzwa kwenzvimbo dzinoshanda dzeNi, catalyst ine chiyero cheV:Ni che1:8 yakaratidza FE yepamusoro uye AA performance muV:Ni ratio screening test. Kuti tijekese kana chiyero cheV:Ni chinoramba chakafanana mushure me electrolysis, kuumbwa kwe catalysts dzakashandiswa kwakatsanangurwa. Zvakawanikwa zvinoratidza kuti kune ma catalysts ane ma V:Ni ratios ekutanga kubva pa1:16 kusvika pa1:4, V:Ni ratio yakaderera kusvika pa1:22 mushure mekuita, izvo zvinogona kunge zvichikonzerwa nekudonhedzwa kweV nekuda kwekugadzirwazve kwe catalyst (Supplementary Fig. 13). Cherechedza kuti ma AA FE akafanana akaonekwa apo chiyero chekutanga che V:Ni chakaenzana kana kupfuura 1:16 (Supplementary Fig. 11f), izvo zvinogona kutsanangurwa nekugadzirwazve kwe catalyst zvichikonzera ma V:Ni ratios akafanana muma catalysts anoratidza kushanda kwakafanana kwe catalytic.
Kuti tisimbise kukosha kweV-modified Ni(OH)2 mukusimudzira mashandiro eCOR, takagadzira dzimwe nzira mbiri dzekugadzira kuti tiise V muzvinhu zveNi(OH)2-NS. Imwe inzira yekusanganisa, uye sample inonzi NiV-MIX; imwe inzira yekusputtering yakatevedzana, uye sample inonzi NiV-SP. Ruzivo rwe synthesis rwuri muchikamu cheMethods. SEM-EDS mapping yakaratidza kuti V yakagadziriswa zvinobudirira pamusoro peNi(OH)2-NS yemasampuli ese ari maviri (Supplementary Fig. 14). Mhedzisiro ye electrolysis inoratidza kuti pa1.8 VRHE, kushanda kweAA pama electrodes eNiV-MIX neNiV-SP kuri 78% ne79%, zvichiteerana, ese achiratidza kushanda kwepamusoro kupfuura Ni(OH)2-NS (51%). Uyezve, OER pama electrodes eNiV-MIX neNiV-SP yakadzvinyirirwa (FE O2: 7% ne2%, zvichiteerana) zvichienzaniswa neNi(OH)2-NS (FE O2: 27%). Mhedzisiro iyi inosimbisa mhedzisiro yakanaka yekuchinja kweV muNi(OH)2 pakudzvinyirirwa kweOER (Mufananidzo 14 wekuwedzera). Zvisinei, kugadzikana kwema catalysts kwakakanganiswa, izvo zvakaratidzwa nekuderera kweFE AA paNiV-MIX kusvika 45% uye paNiV-SP kusvika 35% mushure meCOR cycles nomwe, zvinoreva kudiwa kwekushandisa nzira dzakakodzera dzekugadzirisa marudzi eV, senge kuchinja kweV muNi(OH)2 lattice muNiV-LDH-NS, inova ndiyo catalyst huru mubasa iri.
Takaongororawo kugadzikana kweNi(OH)2-NS neNiV-LDH-NS nekuisa COR muma cycles akawanda. Kuita kwacho kwakaitwa kweawa imwe chete pa cycle uye electrolyte yakatsiviwa mushure me cycle yega yega. Mushure me cycle yechinomwe, mashandiro eFE neAA paNi(OH)2-NS akadzikira ne50% ne60%, zvichiteerana, ukuwo kuwedzera kweOER kwakaonekwa (Mufananidzo 2i, j). Mushure me cycle yega yega, takaongorora cyclic voltammetry (CV) curves dze catalysts uye takaona kuti oxidation peak yeNi2+ yakaderera zvishoma nezvishoma, zvichiratidza kudzikira kwekugona kwe redox kweNi (Mufananidzo Wekuwedzera 15a–c). Pamwe chete nekuwedzera kwehuwandu hweNication mu electrolyte panguva ye electrolysis (Mufananidzo Wekuwedzera 15d), tinoti degradation ye performance (kudzikira kweFE neAA productivity) yakakonzerwa nekubuda kweNi kubva mu catalyst, zvichikonzera kuratidzwa kukuru kweNi foamed substrate inoratidza OER activity. Kusiyana neizvi, NiV-LDH-NS yakaderedza kudzikira kweFE neAA productivity kusvika 10% (Mufananidzo 2i, j), zvichiratidza kuti V modification yakadzivirira Ni leaching zvakanaka (Mufananidzo Wekuwedzera 15d). Kuti tinzwisise kugadzikana kwakawedzerwa kweV modification, takaita maverengero edzidziso. Sekureva kwezvinyorwa zvekare34,35, shanduko ye enthalpy ye demetallization process yemaatomu esimbi pamusoro pe catalyst inogona kushandiswa setsananguro inonzwisisika yekuongorora catalyst stability. Nokudaro, shanduko ye enthalpy ye demetallization process yemaatomu eNi pamusoro (100) we reconstructed Ni(OH)2-NS neNiV-LDH-NS (NiOOH neNiVOOH, zvichiteerana) yakafungidzirwa (tsananguro yekuvakwa kwemuenzaniso inotsanangurwa mu Supplementary Note 2 ne Supplementary Fig. 16). Demetallization process yeNi kubva kuNiOOH neNiVOOH yakaratidzirwa (Mufananidzo Wekuwedzera 17). Mutengo wesimba reNi demetallization paNiVOOH (0.0325 eV) wakakwira kupfuura weNiOOH (0.0005 eV), zvichiratidza kuti kugadziriswa kweV kunowedzera kugadzikana kweNiOOH.
Kuti zvisimbiswe kuti OER inhibitory effect paNiV-LDH-NS, kunyanya pa high anodic potentials, differential electrochemical mass spectrometry (DEMS) yakaitwa kuti iongorore potential-dependent O2 formation pamasample akasiyana. Zvakabuda zvakaratidza kuti kana pasina cyclohexanone, O2 paNiV-LDH-NS yakaonekwa pa 1.53 VRHE, iyo yaive yakaderera zvishoma pane iyo yeO2 paNi(OH)2-NS (1.62 VRHE) (Supplementary Fig. 18). Izvi zvinoratidza kuti OER inhibition yeNiV-LDH-NS panguva yeCOR ingasave nekuda kwebasa rayo remukati reOER rakaderera, iro rinoenderana ne current density yakakwira zvishoma muma curve e linear sweep voltammetry (LSV) paNiV-LDH-NS pane iyo paNi(OH)2-NS isina cyclohexanone (Supplementary Fig. 19). Mushure mekuunzwa kwecyclohexanone, kunonoka kwekushanduka kweO2 (zvichida nekuda kwekubatsira kweCOR mukupisa kwemhepo) kunotsanangura FE yakakwira yeAA munzvimbo ine potential yakaderera. Chinonyanya kukosha ndechekuti, OER inotanga kugona paNiV-LDH-NS (1.73 VRHE) inononoka kupfuura iyo iri paNi(OH)2-NS (1.65 VRHE), izvo zvinoenderana neFE yakakwira yeAA uye FE yakaderera yeO2 paNiV-LDH-NS papotentials dzakanaka (Mufananidzo 2c).
Kuti tinzwisise zvakanyanya mhedzisiro yekusimudzira kweV modification, takaongorora OER neCOR reaction kinetics paNi(OH)2-NS neNiV-LDH-NS nekuyera Tafel slopes dzavo. Zvakakosha kuziva kuti huwandu huripo mudunhu reTafel hunokonzerwa nekuoxidation kweNi2+ kuenda kuNi3+ panguva yeLSV test kubva pa low potential kuenda ku high potential. Kuti tideredze mhedzisiro yeNi2+ oxidation pakuyera COR Tafel slope, takatanga taoxidation catalyst pa1.8 VRHE kwemaminitsi gumi uye takazoita LSV tests mu reverse scan mode, kureva, kubva pa high potential kuenda ku low potential (Supplementary Fig. 20). LSV curve yekutanga yakagadziriswa ne 100% iR compensation kuti tiwane Tafel slope. Kana pasina cyclohexanone, Tafel slope yeNiV-LDH-NS (41.6 mV dec−1) yaive yakaderera pane yeNi(OH)2-NS (65.5 mV dec−1), zvichiratidza kuti OER kinetics inogona kuwedzerwa neV modification (Supplementary Fig. 20c). Mushure mekuiswa kwecyclohexanone, Tafel slope yeNiV-LDH-NS (37.3 mV dec−1) yaive yakaderera pane yeNi(OH)2-NS (127.4 mV dec−1), zvichiratidza kuti V modification yaive nekinetic effect yakajeka paCOR zvichienzaniswa neOER (Supplementary Fig. 20d). Mhedzisiro iyi inoratidza kuti kunyangwe V modification ichisimudzira OER kusvika pamwero wakati, inokurumidza zvikuru COR kinetics, zvichikonzera kuwedzera kweFE yeAA.
Kuti tinzwisise mhedzisiro yekusimudzira kwekushandurwa kweV pamusoro apa pakushanda kweFE neAA, takatarisa pakudzidza kwemuchina. Mimwe mishumo yapfuura yakaratidza kuti kugadziriswa kweheteroatom kunogona kuderedza kristallinity yemacatalysts uye kuwedzera nzvimbo inoshanda yemagetsi (EAS), nokudaro kuwedzera huwandu hwenzvimbo dzinoshanda uye nokudaro kuvandudza catalytic activity36,37. Kuti tiongorore mukana uyu, takaita zviyero zveECSA tisati tatanga uye tapedza electrochemical activation, uye mhedzisiro yakaratidza kuti ECSA yeNi(OH)2-NS neNiV-LDH-NS yaifanana (Supplementary Fig. 21), tichibvisa pesvedzero ye active site density mushure mekushandurwa kweV pakuwedzera catalytic.
Zvinoenderana neruzivo rwunogamuchirwa, muNi(OH)2-catalyzed electrooxidation yealcohols kana mamwe ma nucleophilic substrates, Ni(OH)2 inotanga yarasikirwa nemaerekitironi nemaprotoni yozoderedzwa kuita NiOOH kuburikidza nematanho emagetsi pane imwe anodic potential38,39,40,41. NiOOH yakagadzirwa inobva yashanda semhando chaiyo inoshanda yeCOR kubvisa hydrogen nemaerekitironi kubva kunucleophilic substrate kuburikidza nematanho emakemikari kuti igadzire chigadzirwa chakasanganiswa20,41. Zvisinei, munguva pfupi yapfuura zvakataurwa kuti kunyangwe kuderedzwa kweNiOOH kunogona kushanda sedanho rekusarudza mwero (RDS) we electrooxidation yealcohol paNi(OH)2, sezvakaratidzwa mumabhuku achangoburwa, oxidation yeNi3+ alcohols inogona kunge iri nzira inongoerekana yaitika kuburikidza ne non-redox electron transfer kuburikidza ne non-occupied orbitals yeNi3+41,42. Takafuridzirwa neongororo yemakanika yakataurwa mumabhuku akafanana, takashandisa dimethylglyoxime disodium salt octahydrate (C4H6N2Na2O2 8H2O) seprobe molecule kuti itore chero kuumbwa kweNi2+ kunokonzerwa nekuderedzwa kweNi3+ panguva yeCOR (Supplementary Fig. 22 neSupplementary Note 3). Mhedzisiro yacho yakaratidza kuumbwa kweNi2+, zvichisimbisa kuti kudzikiswa kwemakemikari kweNiOOH uye electrooxidation yeNi(OH)2 kwakaitika panguva imwe chete panguva yeCOR process. Nokudaro, catalytic activity inogona kutsamira zvakanyanya pa kinetics yekuderedzwa kweNi(OH)2 kuenda kuNiOOH. Zvichibva pamusimboti uyu, takazoongorora kana kuchinjwa kweV kuchizokurumidzisa kudzikiswa kweNi(OH)2 uye nokudaro kuvandudza COR.
Takatanga kushandisa matekiniki eRaman aripo kuratidza kuti NiOOH ndiyo nzira inoshanda yeCOR paNi(OH)2-NS uye NiV-LDH-NS nekuona kuumbwa kweNiOOH pa positive potentials uye kushandiswa kwayo mushure mekuunzwa kwecyclohexanone, tichitevera maitiro e "electrochemical-chemical" ataurwa pamusoro apa (Mufananidzo 3a). Uyezve, reactivity yeNiV-LDH-NS yakagadziriswazve yakadarika iyo yeNi(OH)2-NS, sezvinoratidzwa nekutsakatika nekukurumidza kwechiratidzo cheNi3+–O Raman. Takazoratidza kuti NiV-LDH-NS yakaratidza positive potential shoma yekuumbwa kweNiOOH zvichienzaniswa neNi(OH)2-NS mukuvapo kana kusavapo kwecyclohexanone (Mufananidzo 3b, c uye Supplementary Fig. 4c, d). Zvinonyanya kukosha kuti kushanda kweNiV-LDH-NS zvakanaka kunoita kuti mabhuru akawanda anamire pagirazi repamberi rechinangwa chekuyera cheRaman, izvo zvinoita kuti Raman peak pa1.55 VRHE ipere (Supplementary Fig. 4d). Zvichienderana nemhedzisiro yeDEMS (Supplementary Fig. 18), huwandu hwemazuva ano pa low potentials (VRHE < 1.58 yeNi(OH)2-NS uye VRHE < 1.53 yeNiV-LDH-NS) hunonyanya kukonzerwa nekuvakwazve kwemaion eNi2+ pane OER pasina cyclohexanone. Saka, oxidation peak yeNi2+ muLSV curve yakasimba kupfuura yeNiV-LDH-NS, zvichiratidza kuti V modification inopa NiV-LDH-NS kugona kudzokororwa (ona Supplementary Fig. 19 kuti uwane ongororo yakadzama).
a In situ Raman spectra yeNi(OH)2-NS (kuruboshwe) uye NiV-LDH-NS (kurudyi) pasi pemamiriro eOCP mushure me preoxidation pa1.5 VRHE mu 0.5 M KOH uye 0.4 M cyclohexanone kwemasekonzi 60. b In situ Raman spectra yeNi(OH)2-NS uye c NiV-LDH-NS mu 0.5 M KOH + 0.4 M cyclohexanone pama potentials akasiyana. d In situ XANES spectra yeNi(OH)2-NS uye NiV-LDH-NS paNi K-edge mu 0.5 M KOH uye e 0.5 M KOH uye 0.4 M cyclohexanone. Chinyorwa chinoratidza nzvimbo yakakura ye spectral iri pakati pe8342 ne8446 eV. f Valence states yeNi muNi(OH)2-NS uye NiV-LDH-NS pama potentials akasiyana. g In situ Ni EXAFS spectra yeNiV-LDH-NS isati yaiswa cyclohexanone uye mushure mekuiswa kwayo pamatanho akasiyana. h Mamodheru edzidziso eNi(OH)2-NS neNiV-LDH-NS. Pamusoro: PaNi(OH)2-NS, kugadziriswa zvishoma nezvishoma kubva paNi(OH)2-NS kuenda kuNiOOH kunoshanda seRDS, nepo cyclohexanone ichideredza mhando dzeNi dzine valent yakakwirira kuburikidza nematanho emakemikari kuchengetedza mamiriro eNi ane valent yakaderera kuti igadzire AA. Pazasi: PaNiV-LDH-NS, danho rekugadzirisa rinofambiswa nekushandurwa kweV, zvichikonzera kutamiswa kweRDS kubva padanho rekugadzirisa kuenda padanho remakemikari. i Simba remahara reGibbs rinoshanduka pakuvakwazve kweNi(OH)2-NS neNiV-LDH-NS. Data raw re aj ne i rinopihwa mufaira re data raw.
Kuti tiongorore kushanduka kwemaumbirwo eatomu neemagetsi panguva yekuderedza catalyst, takaita bvunzo dze X-ray absorption spectroscopy (XAS) in situ, dzakapa chishandiso chine simba chekuongorora mashandiro eNi species mumatanho matatu akatevedzana: OER, cyclohexanone injection, uye COR at open circuit potential (OCP). Mufananidzo unoratidza K-edge XANES spectra yeNi ine potential inowedzera isati yaiswa cyclohexanone uye mushure meinjection (Mufananidzo 3d, e). Pa potential imwechete, absorption edge energy yeNiV-LDH-NS yakanaka zvikuru kupfuura yeNi(OH)2-NS (Mufananidzo 3d, e, inset). Avhareji yevalence yeNi pasi pemamiriro ese yakafungidzirwa ne linear combined fit yeXANES spectra uye regression yeNi K-edge absorption energy shift (Mufananidzo 3f), ne reference spectrum yakatorwa kubva mumabhuku akaburitswa (Supplementary Fig. 23)43.
Mudanho rekutanga (kusati kwatanga kushandiswa kwecyclohexanone, zvinoenderana nemaitiro eOER; Mufananidzo 3f, kuruboshwe), pamhedzisiro yecatalyst isina kugadziriswa (<1.3 VRHE), mamiriro eNi muNiV-LDH-NS (+1.83) akaderera zvishoma pane eNi(OH)2-NS (+1.97), izvo zvinogona kuverengerwa nekufambiswa kwemaerekitironi kubva kuV kuenda kuNi, zvinoenderana nemhedzisiro yeXPS yataurwa pamusoro apa (Mufananidzo 2f). Kana mhedzisiro yacho ikapfuura poindi yekudzikisa (1.5 VRHE), mamiriro eNi muNiV-LDH-NS (+3.28) anoratidza kuwedzera kuri pachena zvichienzaniswa neNi(OH)2-NS (+2.49). Pamhedzisiro yepamusoro (1.8 VRHE), mamiriro eNi muNi anowanikwa paNiV-LDH-NS (+3.64) akakwira kupfuura eNi(OH)2-NS (+3.47). Sekureva kwemishumo ichangoburwa, maitiro aya anoenderana nekuumbwa kwemhando dzeNi4+ dzine valent ine simba muchimiro cheNi3+xOOH1-x (Ni3+x imhando yakasanganiswa yeNi3+ neNi4+), iyo yakamboratidza kushanda kwakawedzerwa kwe catalytic mukubviswa kwehydrogenation kwedoro38,39,44. Nokudaro, kushanda kwepamusoro kweNiV-LDH-NS muCOR kunogona kunge kuri nekuda kwekuderedzwa kwakawedzerwa kwekugadzira mhando dzeNi dzine valent ine simba ine simba.
Mudanho rechipiri (kutanga kwecyclohexanone mushure mekuvhurwa kweringi, Mufananidzo 3f), mamiriro eNi evalence pa catalysts ese ari maviri akaderera zvakanyanya, izvo zvinoenderana nemaitiro ekuderedza Ni3+xOOH1-x ne cyclohexanone, izvo zvinoenderana nemhedzisiro ye in situ Raman spectroscopy (Mufananidzo 3a), uye mamiriro eNi evalence akapotsa adzokera kumamiriro ekutanga (danho rekutanga pa low potential), zvichiratidza kudzoserwa kwemaitiro e redox eNi3+xOOH1-x.
Mudanho rechitatu (maitiro eCOR) paCOR potentials (1.5 na 1.8 VRHE; Mufananidzo 3f, kurudyi), mamiriro eNi (OH)2-NS akawedzera zvishoma (+2.16 na +2.40), izvo zvakaderera zvakanyanya pane pamasimba akafanana mudanho rekutanga (+2.49 na +3.47). Mhedzisiro iyi inoratidza kuti mushure mekuisirwa cyclohexanone, COR inodzikiswa kinetically ne oxidation inononoka yeNi2+ kuenda kuNi3+x (kureva, kuvakazve kweNi) pane nedanho remakemikari pakati peNiOOH necyclohexanone paNi(OH)2-NS, izvo zvinosiya Ni iri mu low-valence state. Saka, tinogumisa kuti kuvakazve kweNi kunogona kushanda seRDS mumaitiro eCOR paNi(OH)2-NS. Kusiyana neizvi, NiV-LDH-NS yakaramba iine valence yakakwira yeNi species (>3) panguva yeCOR process, uye valence yakaderera zvishoma (pasi pe0.2) zvichienzaniswa nedanho rekutanga pahunhu hwakafanana (1.65 na1.8 VRHE), zvichiratidza kuti V modification yakasimudzira oxidation yeNi2+ kuenda kuNi3+x, zvichiita kuti Ni reduction process ikurumidze kupfuura chemical step ye cyclohexanone reduction. Extended X-ray absorption fine structure (EXAFS) results yakaratidzawo shanduko yakazara yeNi–O (kubva pa1.6 kusvika pa1.4 Å) uye Ni–Ni(V) (kubva pa2.8 kusvika pa2.4 Å) bonds pamberi pe cyclohexanone. Izvi zvinoenderana nekuvakwazve kweNi(OH)2 phase kuenda kuNiOOH phase uye chemical reduction yeNiOOH phase ne cyclohexanone (Mufananidzo 3g). Zvisinei, cyclohexanone yakakanganisa zvakanyanya kuderedzwa kweNi(OH)2-NS (ona Supplementary Note 4 uye Supplementary Fig. 24 kuti uwane rumwe ruzivo).
Pamwe chete, paNi(OH)2-NS (Mufananidzo 3h, pamusoro), danho rekudzikisa zvishoma nezvishoma kubva paNi(OH)2 kuenda kuNiOOH rinogona kushanda seRDS yemaitiro ese eCOR pane danho remakemikari rekuumbwa kweAA kubva kucyclohexanone panguva yekuderedzwa kwemakemikari kweNiOOH. PaNiV-LDH-NS (Mufananidzo 3h, pazasi), shanduko yeV inowedzera oxidation kinetics yeNi2+ kuenda kuNi3+x, nokudaro ichikurumidzisa kuumbwa kweNiVOOH (pane kushandiswa nekudzikiswa kwemakemikari), izvo zvinoshandura RDS kuenda kudanho remakemikari. Kuti tinzwisise kugadziriswa kweNi kunokonzerwa nekushandurwa kweV, takaita mamwe maverengero edzidziso. Sezvakaratidzwa paMufananidzo 3h, takatevedzera maitiro ekuvakazve kweNi(OH)2-NS neNiV-LDH-NS. Mapoka elattice hydroxyl paNi(OH)2-NS neNiV-LDH-NS anobviswa protonation nekubvisa OH- mu electrolyte kuti agadzire lattice oxygen isina maerekitironi. Maitiro emakemikari anoenderana ndeaya anotevera:
Kuchinja kwesimba reGibbs pasina simba rekugadzirisa kwakaverengerwa (Mufananidzo 3i), uye NiV-LDH-NS (0.81 eV) yakaratidza shanduko diki kwazvo yesimba reGibbs pasina simba pane Ni(OH)2-NS (1.66 eV), zvichiratidza kuti kugadziriswa kweV kwakaderedza voltage inodiwa pakuvakazve kweNi. Tinotenda kuti kukurudzira kuvakazve kunogona kuderedza chivharo chesimba cheCOR yese (ona chidzidzo che reaction mechanism pazasi kuti uwane rumwe ruzivo), nokudaro zvichikurumidzisa reaction pahuwandu hwemagetsi akakwira.
Ongororo iri pamusoro apa inoratidza kuti kuchinja kweV kunokonzera kurongwa kweNi(OH)2 nekukurumidza, nokudaro zvichiwedzera reaction rate uye, zvichizowedzera COR current density. Zvisinei, nzvimbo dzeNi3+x dzinogonawo kukurudzira OER activity. Kubva paLSV curve isina cyclohexanone, zviri pachena kuti current density yeNiV-LDH-NS yakakwira kupfuura yeNi(OH)2-NS (Supplementary Fig. 19), izvo zvinoita kuti COR neOER reactions zviite makwikwi. Nokudaro, FE yakakwira zvakanyanya yeAA kupfuura yeNiV-LDH-NS haigone kutsanangurwa zvizere nekuchinja kweV kukurudzira kurongwa kwechikamu.
Zvinogamuchirwa kuti mune alkaline media, maitiro e electrooxidation e nucleophilic substrates anowanzo tevedzera Langmuir–Hinshelwood (LH) model. Kunyanya, substrate ne OH− anions zvinokwikwidzana pamusoro pe catalyst, uye OH− inonyungudutswa ku active hydroxyl groups (OH*), iyo inoshanda se electrophiles yekunyungudutswa kwe nucleophiles, nzira yakaratidzwa kare ne data rekuyedza uye/kana ma theoretical calculations45,46,47. Saka, kuwanda kwema reactants uye chiyero chavo (organic substrate ne OH−) zvinogona kudzora reactant coverage ye catalyst surface, nokudaro zvichikanganisa FE uye goho re product target14,48,49,50. Muchiitiko chedu, tinofungidzira kuti high cyclohexanone surface coverage mu NiV-LDH-NS inofarira COR process, uye zvakasiyana, low cyclohexanone surface coverage mu Ni(OH)2-NS inofarira OER process.
Kuti tiedze fungidziro iri pamusoro apa, takatanga taita miedzo miviri ine chekuita nehuwandu hwema reactants (C, cyclohexanone, uye COH−). Kuedza kwekutanga kwakaitwa ne electrolysis pa constant potential (1.8 VRHE) paNi(OH)2-NS neNiV-LDH-NS catalysts dzine cyclohexanone C content dzakasiyana (0.05 ~ 0.45 M) uye fixed COH− content (0.5 M). Zvadaro, FE neAA productivity zvakaverengerwa. Kune NiV-LDH-NS catalyst, hukama huripo pakati peAA yield necyclohexanone C hwakaratidza "volcanic type" curve yakajairika muLH mode (Mufananidzo 4a), zvichiratidza kuti cyclohexanone coverage yakakwira inokwikwidzana neOH− adsorption. Kunyange zvazvo paNi(OH)2-NS, goho reAA rakawedzera zvishoma nezvishoma nekuwedzera kweC yecyclohexanone kubva pa0.05 kusvika pa0.45 M, zvichiratidza kuti kunyangwe huwandu hwakawanda hwecyclohexanone hwaive hwakakwira (0.45 M), kufukidza kwayo pamusoro kwaive kuchiri kwakaderera. Pamusoro pezvo, nekuwedzera kweCOH− kusvika 1.5 M, "kutenderera kwemhando yegomo" kwakaonekwa paNi(OH)2-NS zvichienderana neC yecyclohexanone, uye inflection point yekushanda yakanonoka kana ichienzaniswa neNiV-LDH-NS, zvichiratidzawo kushoma kwekudzvinyirirwa kwecyclohexanone paNi(OH)2-NS (Supplementary Fig. 25a neNote 5). Pamusoro pezvo, FE yeAA paNiV-LDH-NS yainzwa zvakanyanya C-cyclohexanone uye yakawedzera nekukurumidza kusvika kupfuura 80% apo C-cyclohexanone yakawedzerwa kubva pa0.05 M kusvika pa0.3 M, zvichiratidza kuti cyclohexanone yaiwedzerwa zviri nyore paNiV-LDH-NS (Mufananidzo 4b). Kusiyana neizvi, kuwedzera huwandu hweC-cyclohexanone hakuna kudzivirira zvakanyanya OER paNi(OH)2-NS, izvo zvinogona kunge zvichikonzerwa nekusakwana kwekunyudzwa kwecyclohexanone. Kusiyana neizvi, kuferefeta kwakawedzerwa kweCOH− pakushanda zvakanaka kwecatalytic kwakasimbisawo kuti kunyudzwa kwecyclohexanone kwakavandudzika zvichienzaniswa neNiV-LDH-NS, iyo inogona kutsungirira COH− yakakwira panguva yeCOR process pasina kuderedza FE yeAA (Supplementary Fig. 25b, c uye Note 5).
Kubudirira kweAA neEF ye b Ni(OH)2-NS uye NiV-LDH-NS pa cyclohexanone ine C yakasiyana mu 0.5 M KOH. c Kuwedzerwa kwesimba kwe cyclohexanone pa NiOOH ne NiVOOH. d FE yeAA pa Ni(OH)2-NS uye NiV-LDH-NS mu 0.5 M KOH uye 0.4 M cyclohexanone pa 1.80 VRHE uchishandisa nzira dzisingachinji uye dzinogara dziripo. Mabhawa ezvikanganiso anomiririra kutsauka kwakajairwa kwezviyero zvitatu zvakazvimiririra uchishandisa sample imwe chete uye ari mukati me10%. e Pamusoro: Pa Ni(OH)2-NS, cyclohexanone ine nzvimbo yakaderera yeC inonamirwa zvishoma ne cyclohexanone, zvichikonzera kukwikwidzana kwakasimba kwe OER. Pazasi: Pa NiV-LDH-NS, kuwanda kwe cyclohexanone C munzvimbo yepamusoro kunoonekwa nekuwedzera kwe adsorption ye cyclohexanone, zvichikonzera kudzvinyirirwa kwe OER. Ruzivo rwe a–d rwunowanikwa mufaira re data raw.
Kuti tiedze kuwedzerwa kwekunyudzwa kwecyclohexanone paNiV-LDH-NS, takashandisa electrochemical coupled quartz crystal microbalance (E-QCM) kuti titarise kuchinja kwehuwandu hwemhando dzakanyudzwa munguva chaiyo. Zvakabuda zvakaratidza kuti kugona kwekutanga kwekunyudzwa kwecyclohexanone paNiV-LDH-NS kwaive kwakakura ka1.6 pane kuri paNi(OH)2-NS muOCP state, uye musiyano uyu mukugona kwekunyudzwa wakawedzera sezvo mukana wakawedzera kusvika pa1.5 VRHE (Supplementary Fig. 26). Kuverengerwa kweDFT kwakatenderedzwa nespin kwakaitwa kuti kuongorore maitiro ekunyudzwa kwecyclohexanone paNiOOH neNiVOOH (Mufananidzo 4c). Cyclohexanone inonamira paNi-center paNiOOH nesimba rekunamira (Eads) re -0.57 eV, nepo cyclohexanone ichigona kunamira paNi-center kana V-center paNiVOOH, uko V-center inopa Eads yakaderera (-0.69 eV), zvichienderana nekunamira kwakasimba kwecyclohexanone paNiVOOH.
Kuti tiwedzere kuona kuti kuwedzerwa kwe cyclohexanone kunogona kukurudzira kuumbwa kweAA uye kudzivirira OER, takashandisa nzira yekusagona kuramba tichiita kuti cyclohexanone iwedzere kushanda zvakanaka pamusoro pe catalyst (yeNi(OH)2-NS neNiV-LDH-NS), iyo yakafuridzirwa nemishumo yapfuura. 51, 52 Kunyanya, takashandisa potential ye1.8 VRHE kuCOR, tobva taichinja kuita OCP state, tobva taichinja kuita 1.8 VRHE. Muchiitiko ichi, cyclohexanone inogona kuungana pamusoro pe catalyst muOCP state pakati pe electrolyses (ona chikamu cheMethods kuti uwane maitiro akadzama). Zvakabuda zvakaratidza kuti yeNi(OH)2-NS neNiV-LDH-NS, kushandisa discontinuous potential electrolysis kwakavandudza catalytic performance zvichienzaniswa ne constant potential electrolysis (Mufananidzo 4d). Zvinonyanya kukosha kuti Ni(OH)2-NS yakaratidza kuvandudzika kukuru muCOR (AA FE: kubva pa51% kusvika 82%) uye kudziviswa kweOER (O2 FE: kubva pa27% kusvika 4%) kupfuura NiV-LDH-NS, izvo zvakakonzerwa nekuti kuunganidzwa kwecyclohexanone kunogona kuvandudzwa zvakanyanya pa catalyst ine simba re adsorption capacity (kureva, Ni(OH)2-NS) ne intermittent potential electrolysis.
Kazhinji, kudziviswa kweOER paNiV-LDH-NS kunogona kukonzerwa nekuwedzerwa kwekunyungudika kwecyclohexanone (Mufananidzo 4e). PaNi(OH)2-NS (Mufananidzo 4e, pamusoro), kunyungudika kusina simba kwecyclohexanone kwakaita kuti cyclohexanone ive shoma uye OH* ive yakawanda pamusoro pe catalyst. Nokudaro, mhando dzeOH* dzakawandisa dzichatungamira kumakwikwi akakomba eOER uye kuderedza FE yeAA. Kusiyana neizvi, paNiV-LDH-NS (Mufananidzo 4e, pasi), kugadziriswa kweV kwakawedzera kugona kwekunyungudika kwecyclohexanone, nokudaro zvichiwedzera pamusoro peC yecyclohexanone uye kushandisa zvinobudirira mhando dzeOH* dzakanyungudika dzeCOR, zvichikurudzira kuumbwa kweAA uye kudzivirira OER.
Pamusoro pekuferefeta mhedzisiro yekuchinja kweV pakuvakazve kweNi species uye cyclohexanone adsorption, takaferefetawo kana V ichichinja nzira yekuumbwa kweAA kubva kuCOR. Nzira dzakasiyana-siyana dzeCOR dzakataurwa mumabhuku, uye takaongorora mikana yadzo mu reaction system yedu (ona Supplementary Fig. 27 uye Supplementary Note 6 kuti uwane rumwe ruzivo)13,14,26. Kutanga, zvakashumwa kuti danho rekutanga renzira yeCOR rinogona kusanganisira oxidation yekutanga yecyclohexanone kuti igadzire key intermediate 2-hydroxycyclohexanone (2)13,14. Kuti tisimbise maitiro acho, takashandisa 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO) kubata active intermediates yakanyudzwa pamusoro pe catalyst uye takadzidza EPR. Mhedzisiro yeEPR yakaratidza kuvapo kweC-centered radicals (R) uye hydroxyl radicals (OH) pamacatalysts ese ari maviri panguva yeCOR process, zvichiratidza kuti Cα − H dehydrogenation ye cyclohexanone inoumba intermediate enolate radical (1), iyo inozowedzerwa oxidized ne OH* kuti iumbe 2 (Mufananidzo 5a uye Supplementary Fig. 28). Kunyangwe ma intermediates akafanana akaonekwa pamacatalysts ese ari maviri, chikamu chenzvimbo chechiratidzo cheR paNiV-LDH-NS chaive chakakwira kupfuura cheNi(OH)2-NS, izvo zvinogona kunge zvichikonzerwa nekukwanisa kwakawedzerwa kwe adsorption kwe cyclohexanone (Supplementary Table 3 uye Note 7). Takashandisa zvakare 2 na1,2-cyclohexanedione (3) se reactants yekutanga ye electrolysis kuti tiedze kana V yaizochinja danho rinotevera re oxidation. Mhedzisiro yeelectrolysis ye potential intermediates (2 na 3) paNi(OH)2-NS neNiV-LDH-NS yakaratidza kusarudzwa kwakafanana kwechigadzirwa, zvichiratidza kuti COR reaction paNi(OH)2-NS kana NiV-LDH-NS yaifamba nenzira dzakafanana (Mufananidzo 5b). Uyezve, AA ndiyo yaive chigadzirwa chikuru chete apo 2 yakashandiswa se reactant, zvichiratidza kuti AA yakawanikwa kuburikidza ne direct oxidation process kuburikidza nekutsemuka kweCα − Cβ bond ye2 pane oxidation inotevera kuenda ku3 pama catalysts ese ari maviri, sezvo yakanyanya kushandurwa kuita GA apo 3 yakashandiswa se reactant yekutanga (Supplementary Figures 29, 30).
Chiratidzo cheEPR cheNiV-LDH-NS mu0.5 M KOH + 0.4 M cyclohexanone. b Mhedzisiro yekuongorora kwe electrocatalytic kwe2-hydroxycyclohexanone (2) uye 1,2-cyclohexanedione (3). Electrolysis yakaitwa mu0.5 M KOH uye 0.1 M 2 kana 3 pa1.8 VRE kweawa imwe. Mabhawa ekukanganisa anomiririra kutsauka kwakajairwa kwezviyero zviviri zvakazvimiririra uchishandisa catalyst imwechete. c Nzira dzekuita dzakarongwa dzeCOR pamacatalysts maviri. d Mufananidzo weSchematic wenzira yeCOR paNi(OH)2-NS (kuruboshwe) uye d NiV-LDH-NS (kurudyi). Miseve mitsvuku inoratidza matanho anokurudzirwa neV modification muCOR process. Data raw ye a na b inowanikwa mufaira re data raw.
Zvose zvataurwa, takaratidza kuti Ni(OH)2-NS uye NiV-LDH-NS zvinogadzira COR nenzira yakafanana: cyclohexanone inonyungudutswa pamusoro pe catalyst, yobviswa hydrogen uye inorasikirwa nemaerekitironi kuti iumbe 1, iyo inozooxidized neOH* kuti iumbe 2, ichiteverwa ne multistep transformations kuti igadzire AA (Mufananidzo 5c). Zvisinei, cyclohexanone payakashandiswa se reactant, makwikwi eOER akaonekwa chete paNi(OH)2-NS, nepo huwandu hwakaderera hweokisijeni hwakaunganidzwa apo 2 ne3 zvakashandiswa se reactants. Saka, misiyano yakaonekwa mu catalytic performance inogona kunge iri nekuda kwekuchinja muRDS energy barrier uye cyclohexanone adsorption capacity inokonzerwa nekuchinja kweV pane kuchinja munzira ye reaction. Saka takaongorora RDS ye reaction pathways pama catalysts ese ari maviri. Zvakataurwa pamusoro apa mu X-ray acoustic spectroscopy zvinoratidza kuti V modification inochinja RDS muCOR reaction kubva pa reconstruction stage kuenda pa chemical stage, zvichiita kuti NiOOH phase ne high-valent Ni species zvisaparare paNiV-LDH-NS (Mufananidzo 3f, Supplementary Fig. 24, uye Note 4). Takaongorora zvakare maitiro e reaction anomiririrwa ne current density muchikamu chimwe nechimwe chenzvimbo dzakasiyana dze potential panguva yekuyerwa kweCV (ona Supplementary Fig. 31 uye Note 8 kuti uwane rumwe ruzivo) uye takaita H/D kinetic isotope exchange experiments, izvo zvakaratidza pamwe chete kuti RDS yeCOR paNiV-LDH-NS inosanganisira kutsemuka kweCα − H bond mu chemical stage pane reduction stage (ona Supplementary Fig. 32 uye Note 8 kuti uwane rumwe ruzivo).
Zvichibva pane ongororo iri pamusoro apa, mhedzisiro yese yekuchinja kweV inoratidzwa muMufananidzo 5d. Ni(OH)2-NS uye NiV-LDH-NS catalysts dzinogadziriswazve pamusoro pesimba rakawanda reanodic uye dzinoita kuti COR ishande nenzira yakafanana. PaNi(OH)2-NS (Mufananidzo 5d, kuruboshwe), danho rekuvakazve iRDS panguva yekushanda kweCOR; nepo paNiV-LDH-NS (Mufananidzo 5d, kurudyi), kugadziriswa kweV kwakakurumidzisa zvakanyanya maitiro ekuvakazve uye kwakashandura RDS kuita Cα−H dehydrogenation ye cyclohexanone kuita 1. Pamusoro pezvo, cyclohexanone adsorption yakaitika panzvimbo yeV uye yakawedzerwa paNiV-LDH-NS, izvo zvakabatsira mukudziviswa kweOER.
Tichifunga nezvekushanda kwakanaka kwazvo kwemagetsi eNiV-LDH-NS ine FE yakakwira pamusoro pesimba rakakura, takagadzira MEA kuti tiwane kugadzirwa kweAA kunoenderera mberi. MEA yakaunganidzwa tichishandisa NiV-LDH-NS seanode, commercial PtRu/C se cathode53 uye anion exchange membrane (rudzi: FAA-3-50) (Mufananidzo 6a uye Supplementary Fig. 33)54. Sezvo cell voltage yakaderera uye FE yeAA yakaenzana ne0.5 M KOH muchidzidzo chiri pamusoro apa, anolyte concentration yakagadziriswa kusvika ku1 M KOH (Supplementary Fig. 25c). Ma LSV curves akanyorwa anoratidzwa muSupplementary Fig. 34, zvichiratidza kuti COR efficiency yeNiV-LDH-NS yakakwira zvakanyanya kupfuura yeNi(OH)2-NS. Kuratidza hukuru hweNiV-LDH-NS, electrolysis yemagetsi inoramba iripo yakaitwa nedanho remagetsi rinotangira pa50 kusvika 500 mA cm−2 uye voltage yemasero inoenderana yakanyorwa. Zvakabuda zvakaratidza kuti NiV-LDH-NS yakaratidza voltage yemasero ye1.76 V pahuwandu hwemagetsi hwe300 mA cm−2, iyo yaive yakaderera ne16% pane yeNi(OH)2-NS (2.09 V), zvichiratidza kushanda kwayo nesimba kwakanyanya mukugadzirwa kweAA (Mufananidzo 6b).
Dhiyagiramu yemufananidzo webhatiri rinoyerera. b Voltage yemasero isina iR muripo paNi(OH)2-NS uye NiV-LDH-NS mu1 M KOH uye 0.4 M cyclohexanone pahuwandu hwakasiyana hwemagetsi. c AA neFE goho paNi(OH)2-NS uye NiV-LDH-NS pahuwandu hwakasiyana hwemagetsi. Error bars dzinomiririra kutsauka kwakajairwa kwezviyero zviviri zvakazvimiririra uchishandisa catalyst imwechete. d Kuenzanisa mashandiro ecatalytic ebasa redu nemamwe masisitimu ebhatiri rinoyerera akataurwa14,17,19. Maparamita e reaction uye hunhu hwe reaction zvakanyorwa zvakadzama muSupplementary Table 2. e Voltage yemasero uye FE yeAA paNiV-LDH-NS pa200 uye 300 mA cm−2 mubvunzo wenguva refu, zvichiteerana. Data raw ye be inopiwa sefaira re data raw.
Zvichakadaro, sezvakaratidzwa muMufananidzo 6c, NiV-LDH-NS yakaramba iine FE yakanaka (83% kusvika 61%) pahuwandu hwemagetsi (200 kusvika 500 mA cm-2), nokudaro ichivandudza kugadzirwa kweAA (1031 kusvika 1900 μmol cm-2 h-1). Zvichakadaro, 0.8% chete yeanions yeadipic acid yakaonekwa mu cathode compartment mushure me electrolysis, zvichiratidza kuti shanduko ye cyclohexanone yakanga isina kukosha kwatiri (Muenzaniso Wekuwedzera 35). Kusiyana neizvi, nekuwedzera kumwe chete kwehuwandu hwemagetsi, FE yeAA paNi(OH)2-NS yakaderera kubva pa61% kusvika pa34%, izvo zvakaita kuti zviome kuvandudza kugadzirwa kweAA (762 kusvika 1050 μmol cm-2 h-1). Zvikuru sei, kushanda kweAA kwakatodzikira zvishoma nekuda kwemakwikwi akasimba kubva kuOER, uye nokudaro FE yeAA yakaderera zvakanyanya nekuwedzera kwehuwandu hwezvino (kubva pa200 kusvika 250 mA cm−2, Supplementary Fig. 5). Sekuziva kwedu, mhedzisiro ye catalytic inoshandisa MEA ine NiV-LDH-NS catalysts inodarika zvakanyanya kushanda kwe flow reactors dzakambotaurwa neNi-based catalysts (Supplementary Table 2). Uyezve, sezvakaratidzwa muFig. 6d, NiV-LDH-NS yakaratidza mabhenefiti akakosha maererano ne current density, cell voltage, uye FE yeAA zvichienzaniswa neCo-based catalyst inoshanda zvakanaka, kureva, graphene-supported Co3O4 (Co3O4/GDY)17. Pamusoro pezvo, takaongorora kushandiswa kwesimba reAA mukugadzirwa kweAA uye takaratidza kuti kushandiswa kweAA kwaive kwakaderera zvikuru, 2.4 W h gAA-1 chete pahuwandu hwemazuva ano hwe300 mA cm-2 uye voltage yesero ye1.76 V (kuverenga kwakadzama kwakapihwa muSupplementary Note 1). Zvichienzaniswa nemhedzisiro yakanakisa ye4.1 W h gAA-1 yeCo3O4/GDY yakataurwa kare, kushandiswa kwesimba mukugadzirwa kweAA mubasa redu kwakadzikira ne42% uye kubereka kwakawedzerwa ka4 (1536 vs. 319 μmol cm-2 h-1)17.
Kugadzikana kweNiV-LDH-NS catalyst yekugadzira AA kwenguva refu muMEA kwakaongororwa pahuwandu hwemazuva ano hwe200 ne300 mA cm-2, zvichiteerana (Mufananidzo 6e). Sezvo OH− ichidyiwa nekukurumidza pahuwandu hwemazuva ano hwakakwira, mwero wekuvandudzwa kwe electrolyte pa300 mA cm-2 wakakwira kupfuura uri pa200 mA cm-2 (ona chikamu "Kuyerwa kweElectrochemical" kuti uwane rumwe ruzivo). Pahuwandu hwemazuva ano hwe200 mA cm-2, avhareji yekushanda kweCOR yaive 93% mumaawa matanhatu ekutanga, ndokuzodzikira zvishoma kusvika 81% mushure memaawa makumi matanhatu, nepo voltage yemasero yakawedzera zvishoma ne7% (kubva pa1.62 V kusvika pa1.73 V), zvichiratidza kugadzikana kwakanaka. Nekuwedzera kwehuwandu hwemagetsi kusvika pa300 mA cm−2, kushanda kweAA kwakaramba kusina kuchinja (kwakadzikira kubva pa85% kusvika pa72%), asi voltage yemasero yakawedzera zvakanyanya (kubva pa1.71 kusvika pa2.09 V, zvichienderana ne22%) panguva yebvunzo yemaawa makumi mana nematanhatu (Mufananidzo 6e). Tinofungidzira kuti chikonzero chikuru chekuderera kwekushanda ndiko kukora kwe anion exchange membrane (AEM) ne cyclohexanone, izvo zvinotungamira mukuwedzera kwekudzivirira kwemasero uye voltage ye electrolyzer cell (Supplementary Fig. 36), pamwe chete nekubuda kwe electrolyte kubva ku anode kuenda ku cathode, zvichikonzera kudzikira kwe anolyte volume uye kudiwa kwekumisa electrolysis. Pamusoro pezvo, kudzikira kwe FE yeAA kunogonawo kunge kuri nekuda kwekubuda kwe catalysts, izvo zvinokurudzira kuvhurwa kwe Ni foam ye OER. Kuti tiratidze kukanganiswa kweAEM yakaora pakuora kwekugadzikana pa300 mA cm−2, takaitsiva neAEM itsva mushure memaawa makumi mana nematanhatu e electrolysis. Sezvaitarisirwa, kushanda zvakanaka kwe catalytic kwakadzoserwa zviri pachena, ne cell voltage ichiderera zvakanyanya kusvika pakuvamba kwekutanga (kubva pa2.09 kusvika pa1.71 V) uye yozowedzera zvishoma mukati memaawa gumi nemaviri anotevera e electrolysis (kubva pa1.71 kusvika pa1.79 V, kuwedzera kwe5%; Mufananidzo 6e).
Zvose zvakazara, takakwanisa kuwana kugadzikana kwekugadzirwa kweAA kwemaawa makumi matanhatu (60 h) pahuwandu hwemagetsi hwe200 mA cm−2, zvichiratidza kuti FE nemagetsi emasero eAA zvinochengetwa zvakanaka. Takaedzawo huwandu hwemagetsi hwe300 mA cm−2 uye takawana kugadzikana kwemaawa makumi mashanu nemasere, tichitsiva AEM neimwe itsva mushure memaawa makumi mana nematanhatu. Zvidzidzo zviri pamusoro apa zvinoratidza kugadzikana kwecatalyst uye zvinoratidza zvakajeka kudiwa kwekuvandudzwa kweAEMs dzine simba guru mune ramangwana kuti tivandudze kugadzikana kwenguva refu kweMEA kwekugadzirwa kweAA nguva dzose pahuwandu hwemagetsi hwakakodzera muindasitiri.
Zvichibva pakushanda kweMEA yedu, takapa zano rekugadzira AA yakazara inosanganisira kudya substrate, electrolysis, neutralization, uye separation units (Supplementary Fig. 37). Ongororo yekutanga yekushanda kwakaitwa kuti iongorore kugona kwehupfumi hwesystem uchishandisa alkaline electrolyte electrocatalytic carboxylate production model55. Muchiitiko ichi, mari inosanganisira capital, operations, uye materials (Fig. 7a neSupplementary Fig. 38), uye mari inobva mukugadzirwa kweAA neH2. Mhedzisiro yeTEA inoratidza kuti pasi pemamiriro edu ekushanda (current density 300 mA cm-2, cell voltage 1.76 V, FE 82%), mari yese nemari inowanikwa iUS$2429 neUS$2564, zvichiteerana, zvichishandura kuita purofiti yeUS$135 patani yeAA yakagadzirwa (ona Supplementary Note 9 kuti uwane rumwe ruzivo).
a Mutengo wose weAA electrochemical process pasi pe base case scenario ine FE ye82%, current density ye300 mA cm−2, uye cell voltage ye1.76 V. Kuongorora kwe sensitivity yemitengo mitatu ku b FE uye c current density. Mukuongorora kwe sensitivity, ma parameter akadzidzwa chete ndiwo akachinjwa uye mamwe ma parameter akachengetedzwa akafanana zvichibva pa TEA model. d Mhedzisiro ye FE yakasiyana uye current density paprofit ye ​​AA electrosynthesis uye purofiti uchishandisa Ni(OH)2-NS uye NiV-LDH-NS, tichifunga kuti cell voltage inochengetwa yakafanana pa 1.76 V. Data rekupinda re a–d rinopihwa mu raw data file.
Zvichibva papfungwa iyi, takaongorora zvakare kukanganisa kweFE uye huwandu hwemagetsi pakubudirira kweAA electrosynthesis. Takaona kuti purofiti inonyanya kuenderana neFE yeAA, sezvo kudzikira kweFE kunotungamira mukuwedzera kukuru kwemutengo wekushanda, nokudaro zvichiwedzera zvakanyanya mutengo wese (Mufananidzo 7b). Nezvehuwandu hwemagetsi huripo, huwandu hwemagetsi hwakakwira (>200 mA cm-2) hunobatsira kuderedza mutengo wemari uye mutengo wekuvaka fekitari, kunyanya nekuderedza nzvimbo yemasero emagetsi, nokudaro zvichibatsira mukuwedzera kwepurofiti (Mufananidzo 7c). Zvichienzaniswa nehuwandu hwemagetsi huripo, FE ine simba guru pakubudirira. Nekutsanangura kukanganisa kweFE uye huwandu hwemagetsi huripo papurofiti, tinoona zvakajeka kukosha kwekuwana FE yakakwira (>60%) pahuwandu hwemagetsi hunoenderana nemaindasitiri (>200 mA cm-2) kuti tive nechokwadi chekuti purofiti inowanikwa. Nekuda kwekuwanda kweFE kweAA, reaction system ine NiV-LDH-NS secatalyst inoramba yakanaka pakati pe100–500 mA cm−2 (pentagram dots; Mufananidzo 7d). Zvisinei, kune Ni(OH)2-NS, kuderedza FE pa high current density (>200 mA cm−2) kwakakonzera mhedzisiro isina kunaka (denderedzwa; Mufananidzo 7d), zvichiratidza kukosha kwe catalysts dzine high FE pa high current density.
Pamusoro pekukosha kwezvinokonzera simba mukuderedza mari yekushandisa, ongororo yedu yeTEA inoratidza kuti purofiti inogona kuvandudzwa nenzira mbiri. Yekutanga ndeyekutengesa pamwe chete potassium sulfate (K2SO4) pamusika sechinhu chinobva kuchikamu che neutralization, asi nekuwana mari inosvika US$828/t AA-1 (Supplementary Note 9). Yechipiri ndeyekuvandudza tekinoroji yekugadzirisa, kusanganisira kudzokorodza zvinhu kana kugadzira matekinoroji ekuparadzanisa AA asingadhuri (mamwe mayuniti e neutralization nekuparadzanisa). Maitiro e acid-base neutralization ari kushandiswa parizvino anogona kukonzera mitengo yakakwira yezvinhu (izvo zvinoita kuti ive chikamu chikuru pa85.3%), iyo 94% inokonzerwa ne cyclohexanone neKOH ($2069/t AA-1; Mufananidzo 7a), asi sezvambotaurwa pamusoro apa, maitiro acho achiri purofiti. Tinokurudzira kuti mari yezvinhu inogona kuderedzwa zvakanyanya nenzira dzepamusoro dzekudzorera KOH uye cyclohexanone isina kugadziriswa, dzakadai se electrodialysis yekudzosa KOH14 zvizere (mutengo unofungidzirwa weUS$1073/t AA-1 kuburikidza ne electrodialysis; Supplementary Note 9).
Muchidimbu, takawana kushanda zvakanaka kweatomu yealuminium electrolysis pahuwandu hwemagetsi epamusoro nekuisa V muNi(OH)2 nanosheets. Pasi pehuwandu hwakawanda hwe1.5–1.9 VRHE uye huwandu hwemagetsi epamusoro e170 mA cm−2, AA FE paNiV-LDH-NS yakasvika 83–88%, nepo OER yakadzvinyirirwa kusvika 3%. Kugadziriswa kweV kwakasimudzira kudzikiswa kweNi2+ kuenda kuNi3+x uye kwakawedzera adsorption yecyclohexanone. Ruzivo rwekuyedza uye rwedzidziso runoratidza kuti kuvakazve kwakakurudzirwa kunowedzera huwandu hwemagetsi ecyclohexanone oxidation uye kunochinja RDS yeCOR kubva pakuvakazve kuenda ku dehydrogenation inosanganisira Cα − H scission, nepo adsorption yakawedzerwa yecyclohexanone ichidzvinyirira OER. Kuvandudzwa kweMEA kwakaita kuti pave nekugadzirwa kweAA kunoenderera mberi pahuwandu hwemagetsi emuindasitiri hwe300 mA cm−2, kushanda zvakanaka kweAA kwe82%, uye kubereka kwe1536 μmol cm−2 h−1. Bvunzo yemaawa makumi mashanu yakaratidza kuti NiV-LDH-NS ine kugadzikana kwakanaka sezvo ichigona kuchengetedza AA FE yakakwira muMEA (> 80% kwemaawa makumi matanhatu pa200 mA cm−2; > 70% kwemaawa makumi mashanu nemasere pa300 mA cm−2). Zvinofanira kucherechedzwa kuti pane chikonzero chekugadzira maAEM ane simba kuti pave nekugadzikana kwenguva refu pahuwandu hwemagetsi hwakakodzera muindasitiri. Pamusoro pezvo, TEA inoratidza zvakanakira zvehupfumi zvemaitiro ekuita kweAA uye kukosha kwemacatalyst anoshanda zvakanyanya uye matekinoroji ekuparadzanisa epamusoro kuti aderedze mari.