ꢀ
LiꢀLiuꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ1070–1075ꢀ
1073ꢀ
Tableꢀ1ꢀ
2
FEꢀ(%)ꢀofꢀtheꢀformationꢀofꢀethanolꢀandꢀn‐propanolꢀuponꢀCO ꢀreductionꢀonꢀtheꢀdifferentꢀelectrodes.ꢀ
Oxide‐derivedꢀCuꢀ
Ethanolꢀ n‐Propanolꢀ
—ꢀ —ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ModifiedꢀbyꢀNiꢀ ModifiedꢀbyꢀZnꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ModifiedꢀbyꢀAuꢀ
Ethanolꢀ n‐Propanolꢀ
Eꢀ(Vꢀvs.ꢀSCE)ꢀ
Ethanolꢀ
n‐Propanolꢀ
Ethanolꢀ
n‐Propanolꢀ
−1.2ꢀ
−1.3ꢀ
−1.4ꢀ
−1.5ꢀ
−1.6ꢀ
ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
—ꢀ
1.0ꢀ
—ꢀ
1.0ꢀ
0.8ꢀ
0.9ꢀ
—ꢀ
0.5ꢀ
1.0ꢀ
1.0ꢀ
0.5ꢀ
1.6ꢀ
1.4ꢀ
0.9ꢀ
2.7ꢀ
2.3ꢀ
1.0ꢀ
1.2ꢀ
1.6ꢀ
0.5ꢀ
1.6ꢀ
2.0ꢀ
0.3ꢀ
0.2ꢀ
0.8ꢀ
ciencyꢀ ofꢀ theꢀ formationꢀ ofꢀ ethanolꢀ andꢀ n‐propanol.ꢀ Onꢀ ox‐
ide‐derivedꢀCu,ꢀatꢀpotentialsꢀofꢀ−1.2ꢀandꢀ−1.3ꢀV,ꢀformicꢀacidꢀwasꢀ
theꢀonlyꢀliquid‐phaseꢀproductꢀdetected,ꢀandꢀtheꢀcorrespondingꢀ
Faradayꢀ efficienciesꢀ wereꢀ 5.6%ꢀ andꢀ 15.0%.ꢀ Atꢀ moreꢀ negativeꢀ
potentialsꢀ (−1.4ꢀ toꢀ −1.6ꢀ V),ꢀ theꢀ Faradayꢀ efꢁiciencyꢀ ofꢀ theꢀ for‐
mationꢀofꢀformicꢀacidꢀgenerallyꢀincreasedꢀwithꢀincreasingꢀpo‐
tentials,ꢀ andꢀ smallꢀ amountsꢀ ofꢀ ethanolꢀ andꢀ n‐propanolꢀ wereꢀ
detected.ꢀ ꢀ
Tableꢀ2ꢀ
Faradayꢀ efficiencyꢀ (%)ꢀ ofꢀ theꢀ formationꢀ ofꢀ gasꢀ productsꢀ onꢀ theꢀ ox‐
ide‐derivedꢀCuꢀandꢀNi‐modifiedꢀoxide‐derivedꢀCuꢀelectrodes.ꢀ
Oxide‐derivedꢀCuꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ModifiedꢀbyꢀNiꢀ
Eꢀ(Vꢀvs.ꢀSCE)
H
2
ꢀ
COꢀ
C
2
H ꢀ
4
H ꢀ
2
COꢀ
C
2 4
H ꢀ
−1.3ꢀ
−1.4ꢀ
−1.5ꢀ
27.5ꢀ
36.7ꢀ
49.9ꢀ
39.7ꢀ
17.4ꢀ
ꢀ 6.6ꢀ
ꢀ 5.7ꢀ
ꢀ 8.2ꢀ
14.2ꢀ
32.5ꢀ
37.6ꢀ
57.0ꢀ
31.6ꢀ
44.6ꢀ
ꢀ 8.4ꢀ
4.6ꢀ
1.0ꢀ
2.9ꢀ
Niꢀmodificationꢀofꢀtheꢀoxide‐derivedꢀCuꢀelectrodeꢀincreasedꢀ
theꢀ Faradayꢀ efficiencyꢀ ofꢀ theꢀ formationꢀ ofꢀ formicꢀ acidꢀ andꢀ
n‐propanol.ꢀ Theꢀ alcoholꢀ productsꢀ wereꢀ detectedꢀ atꢀ appliedꢀ
reductionꢀpotentialsꢀrangingꢀfromꢀ−1.4ꢀtoꢀ−1.6ꢀV.ꢀAtꢀ−1.5ꢀV,ꢀtheꢀ
Faradayꢀefficiencyꢀofꢀtheꢀformationꢀofꢀformicꢀacidꢀwasꢀ30.0%,ꢀ
andꢀthoseꢀofꢀethanolꢀandꢀn‐propanolꢀwereꢀ1.6%ꢀandꢀ2.7%,ꢀre‐
spectively.ꢀ Theseꢀ valuesꢀ wereꢀ higherꢀ thanꢀ theꢀ correspondingꢀ
valuesꢀobtainedꢀonꢀtheꢀunmodifiedꢀoxide‐derivedꢀCuꢀelectrode.ꢀ ꢀ
ToꢀunderstandꢀtheꢀrationalesꢀforꢀtheꢀhighꢀFaradayꢀefficiencyꢀ
obtainedꢀforꢀtheꢀNi‐modifiedꢀelectrode,ꢀtheꢀgas‐phaseꢀproductsꢀ
electrodeꢀwasꢀCOꢀowingꢀtoꢀitsꢀweakꢀbondꢀwithꢀCO.ꢀOnceꢀCO
reducedꢀtoꢀCO,ꢀCOꢀeasilyꢀdesorbsꢀfromꢀtheꢀsurface;ꢀtherefore,ꢀ
furtherꢀreductionꢀisꢀdifficultꢀ[20].ꢀ
2
ꢀisꢀ
4.ꢀ ꢀ Conclusionsꢀ
TheꢀeffectꢀofꢀmodificationꢀofꢀNi,ꢀZn,ꢀandꢀAuꢀofꢀoxide‐derivedꢀ
Cuꢀ electrodeꢀ onꢀ CO ꢀ reductionꢀ wasꢀ investigated.ꢀ Formicꢀ acidꢀ
2
wasꢀobtainedꢀasꢀtheꢀmainꢀliquidꢀproductꢀonꢀallꢀelectrodes.ꢀTheꢀ
Ni‐modifiedꢀ electrodeꢀ showedꢀ theꢀ highestꢀ Faradayꢀ efficiencyꢀ
towardꢀtheꢀformationꢀofꢀformicꢀacidꢀandꢀn‐propanolꢀamongꢀallꢀ
theꢀelectrodesꢀstudied.ꢀ
ofꢀCO
ꢀreductionꢀonꢀtheꢀoxide‐derivedꢀCuꢀandꢀNi‐modifiedꢀox‐
2
ide‐derivedꢀ Cuꢀ electrodesꢀ wereꢀ analyzedꢀ byꢀ onlineꢀ gasꢀ chro‐
matography.ꢀAsꢀshownꢀinꢀTableꢀ2,ꢀNiꢀmodificationꢀsignificantlyꢀ
increasedꢀtheꢀyieldꢀofꢀCO.ꢀNiꢀhasꢀaꢀsmallerꢀatomicꢀradiusꢀ(rꢀ=ꢀ
Referencesꢀ
0.1246ꢀnm)ꢀthanꢀCuꢀ(rꢀ=ꢀ0.1278ꢀnm).ꢀHence,ꢀmodificationꢀofꢀCuꢀ
withꢀNiꢀisꢀexpectedꢀtoꢀinstigateꢀlatticeꢀcontractionꢀwhenꢀcom‐
paredꢀ withꢀ pureꢀ Cu.ꢀ Suchꢀ aꢀ geometricꢀ strainꢀ willꢀ resultꢀ inꢀ aꢀ
downshiftꢀ ofꢀ theꢀ d‐bandꢀ center,ꢀ whichꢀ decreasesꢀ theꢀ bindingꢀ
energyꢀ ofꢀ COꢀ [13].ꢀ Asꢀ aꢀ result,ꢀ theꢀ Ni‐modifiedꢀ Cuꢀ willꢀ yieldꢀ
moreꢀlow‐degreeꢀreducedꢀproductsꢀ(COꢀandꢀHCOOH)ꢀthanꢀpureꢀ
Cu.ꢀPreviously,ꢀTodorokiꢀandꢀcoworkersꢀ[14]ꢀhaveꢀalsoꢀreport‐
edꢀthatꢀmonolayerꢀandꢀsub‐monolayerꢀNiꢀonꢀtheꢀCu(111)ꢀsur‐
faceꢀincreaseꢀtheꢀyieldꢀofꢀCO.ꢀAsꢀforꢀtheꢀincreaseꢀofꢀmulti‐carbonꢀ
alcohols,ꢀtheꢀadditionꢀofꢀNiꢀmayꢀpromoteꢀcouplingꢀofꢀC–Cꢀbonds.ꢀ
Znꢀmodificationꢀofꢀtheꢀoxide‐derivedꢀCuꢀelectrodeꢀdecreasedꢀ
theꢀ Faradayꢀ efficiencyꢀ ofꢀ theꢀ formationꢀ ofꢀ formicꢀ acidꢀ inꢀ theꢀ
potentialꢀrangeꢀstudied.ꢀInꢀtheꢀpotentialꢀrangeꢀofꢀ−1.4ꢀtoꢀ−1.6ꢀV,ꢀ
smallꢀ amountsꢀ ofꢀ alcohols,ꢀ includingꢀ ethanolꢀ andꢀ n‐propanol,ꢀ
wereꢀdetected,ꢀandꢀtheꢀFaradayꢀefficienciesꢀofꢀtheꢀformationꢀofꢀ
theꢀ alcoholsꢀ wereꢀ slightlyꢀ higherꢀ thanꢀ thoseꢀ obtainedꢀ onꢀ theꢀ
unmodifiedꢀoxide‐derivedꢀCuꢀelectrode.ꢀTheseꢀresultsꢀindicateꢀ
thatꢀtheꢀintroductionꢀofꢀZnꢀfacilitatesꢀtheꢀhydrogenationꢀofꢀin‐
termediateꢀproductsꢀslightly.ꢀ ꢀ
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