Cathode made of compacted silver nanoparticles for electrocatalytic carboxylation of 1-phenethyl bromide with CO2

Article abstract of DOI:10.1016/S1872-2067(15)61075-0

Silver nanoparticles prepared by the direct reduction of AgNO₃ in aqueous solution were compacted into coins and used as the cathode for the electrocatalytic carboxylation of 1-phenethyl bromide with CO₂. The influences of the working electrode, charge, current density and temperature were investigated. Under optimized conditions, 98% yield of 2-phenylpropionic acid was obtained. The reaction was performed under very mild conditions and no added catalyst was required in the electrolyte. Yields that varied from moderate to excellent were also achieved with other benzyl bromides. This electrode has good stability and reusability, and the yield and selectivity of 2-phenylpropionic acid could be maintained during reuse for 10 times.

Full text of DOI:10.1016/S1872-2067(15)61075-0

ChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ994–998
ꢀ
ꢀ ꢀ ꢀ
ꢀ ꢀ ꢀ ꢀ
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
ꢀ
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
ꢀ
ꢀ
Communication (Special Issue on Electrocatalysis Transformation)
Cathodeꢀmadeꢀofꢀcompactedꢀsilverꢀnanoparticlesꢀforꢀelectrocatalyticꢀ
carboxylationꢀofꢀ1‐phenethylꢀbromideꢀwithꢀCO ꢀ
2
ꢀa
ꢀb
ꢀa,
ꢀa,#
HengpanꢀYang ,ꢀLaxiaꢀWu ,ꢀHuanꢀWang *,ꢀJiaxingꢀLu
ꢀ
aꢀShanghaiꢀKeyꢀLaboratoryꢀofꢀGreenꢀChemistryꢀandꢀChemicalꢀProcesses,ꢀSchoolꢀofꢀChemistryꢀandꢀMolecularꢀEngineering,ꢀEastꢀChinaꢀNormalꢀUniversity,ꢀ
Shanghaiꢀ200062,ꢀChinaꢀ
bꢀSchoolꢀofꢀChemistryꢀandꢀChemicalꢀEngineering,ꢀAnqingꢀNormalꢀUniversity,ꢀAnqingꢀ246011,ꢀAnhui,ꢀChinaꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
SilverꢀnanoparticlesꢀpreparedꢀbyꢀtheꢀdirectꢀreductionꢀofꢀAgNO ꢀinꢀaqueousꢀsolutionꢀwereꢀcompactedꢀ
3
Receivedꢀ2ꢀFebruaryꢀ2016ꢀ
Acceptedꢀ29ꢀFebruaryꢀ2016ꢀ
Publishedꢀ5ꢀJulyꢀ2016ꢀ
intoꢀcoinsꢀandꢀusedꢀasꢀtheꢀcathodeꢀforꢀtheꢀelectrocatalyticꢀcarboxylationꢀofꢀ1‐phenethylꢀbromideꢀ
withꢀCO .ꢀTheꢀinfluencesꢀofꢀtheꢀworkingꢀelectrode,ꢀcharge,ꢀcurrentꢀdensityꢀandꢀtemperatureꢀwereꢀ
investigated.ꢀUnderꢀoptimizedꢀconditions,ꢀ98%ꢀyieldꢀofꢀ2‐phenylpropionicꢀacidꢀwasꢀobtained.ꢀTheꢀ
reactionꢀwasꢀperformedꢀunderꢀveryꢀmildꢀconditionsꢀandꢀnoꢀaddedꢀcatalystꢀwasꢀrequiredꢀinꢀtheꢀelec‐
trolyte.ꢀYieldsꢀthatꢀvariedꢀfromꢀmoderateꢀtoꢀexcellentꢀwereꢀalsoꢀachievedꢀwithꢀotherꢀbenzylꢀbro‐
mides.ꢀ Thisꢀ electrodeꢀ hasꢀ goodꢀ stabilityꢀ andꢀ reusability,ꢀ andꢀ theꢀ yieldꢀ andꢀ selectivityꢀ ofꢀ
2
Keywords:ꢀ
Electrocatalysisꢀ
Electrocarboxylationꢀ
Carbonꢀdioxideꢀ
Benzylꢀbromidesꢀ
Silverꢀnanoparticles
2‐phenylpropionicꢀacidꢀcouldꢀbeꢀmaintainedꢀduringꢀreuseꢀforꢀ10ꢀtimes.ꢀ
©ꢀ2016,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
CO
2
ꢀ isꢀ theꢀ mainꢀ greenhouseꢀ gasꢀ linkedꢀ toꢀ undesirableꢀ cli‐
[10–12].ꢀ Althoughꢀ highꢀ yieldsꢀ haveꢀ beenꢀ reportedꢀ byꢀ someꢀ
workers,ꢀtheꢀdisadvantagesꢀareꢀalsoꢀobvious,ꢀwhichꢀareꢀthatꢀtheꢀ
transitionꢀmetalꢀcatalystsꢀareꢀbothꢀexpensiveꢀandꢀhardlyꢀrecy‐
clable,ꢀ whichꢀ causeꢀ difficultyꢀ inꢀ practicalꢀ application.ꢀ Electro‐
catalysisꢀwasꢀalsoꢀdemonstratedꢀtoꢀbeꢀanꢀefficientꢀmethodꢀforꢀ
theꢀsynthesisꢀofꢀphenylpropionicꢀacidsꢀbyꢀusꢀ[13,14]ꢀandꢀotherꢀ
workersꢀ [15,16].ꢀ Itꢀ canꢀ beꢀ performedꢀ underꢀ mildꢀ conditionsꢀ
withoutꢀ aꢀ transitionꢀ metalꢀ catalyst.ꢀ Forꢀ example,ꢀ Isseꢀ andꢀ
coworkersꢀ [15]ꢀ reportedꢀ aꢀ synthesisꢀ ofꢀ benzoicꢀ acidꢀ byꢀ theꢀ
mateꢀchange.ꢀOnꢀtheꢀotherꢀhand,ꢀCO
andꢀ cleanꢀ C1ꢀ feedstockꢀ [1].ꢀ Inꢀ recentꢀ years,ꢀ muchꢀ effortꢀ hasꢀ
beenꢀ madeꢀ toꢀ developꢀ effectiveꢀ processesꢀ forꢀ economicalꢀ
productsꢀ byꢀ theꢀ fixationꢀ ofꢀ CO
phenylpropionicꢀacidsꢀfromꢀtheꢀcarboxylationꢀofꢀphenylꢀhalidesꢀ
withꢀCO ꢀhaveꢀcommercialꢀimportanceꢀbecauseꢀofꢀtheirꢀexten‐
siveꢀapplicationsꢀinꢀpharmaceuticalꢀindustry.ꢀTheyꢀareꢀusedꢀasꢀ
intermediatesꢀ forꢀ nonsteroidalꢀ antiinflammatoryꢀ drugsꢀ
2
ꢀisꢀalsoꢀaꢀcheap,ꢀabundantꢀ
2
ꢀ [2–8].ꢀ Amongꢀ theseꢀ products,ꢀ
2
(NSAIDs),ꢀ likeꢀ Ibuprofen,ꢀ Naproxen,ꢀ Ketoprofenꢀ andꢀ Flurbi‐
electrocatalyticꢀreductionꢀofꢀbromobenzeneꢀwithꢀCO
2
ꢀthatꢀgaveꢀ
profen.ꢀMuchꢀattentionꢀhasꢀbeenꢀpaidꢀtoꢀdevelopingꢀsynthesisꢀ
methodsꢀofꢀphenylpropionicꢀacidsꢀ[9].ꢀ ꢀ
However,ꢀaꢀhomogeneousꢀcatalyticꢀsystemꢀforꢀtheꢀsynthesisꢀ
ofꢀ phenylpropionicꢀ acidsꢀ involvesꢀ theꢀ utilizationꢀ ofꢀ transitionꢀ
metalꢀcatalysts,ꢀsuchꢀasꢀcobalt,ꢀnickelꢀandꢀpalladiumꢀcomplexesꢀ
benzoicꢀacidꢀyieldsꢀofꢀ80%.ꢀ
Inꢀourꢀformerꢀwork,ꢀweꢀinvestigatedꢀaꢀrouteꢀforꢀtheꢀelectro‐
catalyticꢀ asymmetricꢀ carboxylationꢀ ofꢀ achiralꢀ 1‐phenylethylꢀ
2
chlorideꢀ withꢀ CO ꢀ inꢀ theꢀ presenceꢀ ofꢀ aꢀ chiralꢀ cobaltꢀ complex.ꢀ
Underꢀoptimizedꢀconditions,ꢀopticallyꢀactiveꢀ2‐phenylpropionicꢀ
*
ꢀ
ꢀCorrespondingꢀauthor.ꢀTel:ꢀ+86‐21‐52134935;ꢀE‐mail:ꢀhwang@chem.ecnu.edu.cnꢀ
Correspondingꢀauthor.ꢀTel:ꢀ+86‐21‐62233491;ꢀE‐mail:ꢀjxlu@chem.ecnu.edu.cnꢀ
#
ThisꢀworkꢀwasꢀsupportedꢀbyꢀtheꢀNationalꢀNaturalꢀScienceꢀFoundationꢀofꢀChinaꢀ(21203066,ꢀ21373090,ꢀ21473060).ꢀ
DOI:ꢀ10.1016/S1872‐2067(15)61075‐0ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ37,ꢀNo.ꢀ7,ꢀJulyꢀ2016ꢀ ꢀ ꢀ

ꢀ
HengpanꢀYangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ994–998ꢀ
995ꢀ
acidꢀwithꢀ37%ꢀyieldꢀandꢀ83%ꢀeeꢀwasꢀobtainedꢀ[17].ꢀInꢀaddition,ꢀ
weꢀ alsoꢀ preparedꢀ aꢀ [Co]@Agꢀ compositeꢀ forꢀ asymmetricꢀ car‐
(a)
(c)
(e)
(b)
boxylationꢀ ofꢀ 1‐phenylethylꢀ bromideꢀ withꢀ CO
2
.ꢀ
2‐phenylpropionicꢀ acidꢀ withꢀ 58%ꢀ yieldꢀ andꢀ 73%ꢀ eeꢀ wasꢀ
achievedꢀ atꢀ normalꢀ pressureꢀ andꢀ temperatureꢀ [18].ꢀ Althoughꢀ
opticallyꢀ activeꢀ productsꢀ wereꢀ obtainedꢀ withꢀ aꢀ chiralꢀ cobaltꢀ
catalyst,ꢀtheꢀyieldꢀwasꢀrelativelyꢀlow,ꢀwhichꢀneedꢀfurtherꢀwork.ꢀ
Inꢀthisꢀwork,ꢀsilverꢀnanoparticlesꢀ(AgꢀNPs)ꢀwereꢀpreparedꢀ
(d)
3
byꢀ theꢀ directꢀ reductionꢀ ofꢀ AgNO ꢀ withꢀ hydrazineꢀ hydrateꢀ
(N
2
H
4
·H O)ꢀinꢀaqueousꢀsolution.ꢀAꢀpowderꢀwithꢀtypicalꢀmetallicꢀ
2
(
2)
propertiesꢀwasꢀobtainedꢀafterꢀfiltrationꢀandꢀdrying.ꢀThisꢀcanꢀbeꢀ
easilyꢀcompactedꢀintoꢀaꢀcoinꢀusingꢀaꢀtabletꢀpressꢀ(Fig.ꢀ1)ꢀandꢀ
usedꢀ asꢀ theꢀ cathodeꢀ forꢀ theꢀ electrocatalyticꢀ carboxylationꢀ ofꢀ
(1)
2
1‐phenylethylꢀ bromideꢀ withꢀ CO .ꢀ Itꢀ shouldꢀ beꢀ notedꢀ thatꢀ thisꢀ
20
40
60
80
o
2
/( )
coinꢀwasꢀpreparedꢀfromꢀpureꢀAgꢀNPsꢀpowderꢀwithoutꢀaꢀsupportꢀ
orꢀcarrier.ꢀBothꢀtheꢀsynthesisꢀofꢀtheꢀAgꢀNPsꢀcathodeꢀandꢀcar‐
boxylationꢀwereꢀperformedꢀunderꢀveryꢀmildꢀconditions,ꢀandꢀnoꢀ
otherꢀcatalystꢀwasꢀneeded.ꢀ
(f)
3
ForꢀtheꢀsynthesisꢀofꢀAgꢀNPs,ꢀ1.7ꢀgꢀAgNO ꢀwasꢀdissolvedꢀinꢀ
100ꢀmLꢀdeionizedꢀwater.ꢀAfterꢀ10ꢀminꢀstirring,ꢀ50ꢀmLꢀhydra‐
zineꢀhydrateꢀsolutionꢀ(10%)ꢀwasꢀadded,ꢀandꢀtheꢀmixtureꢀwasꢀ
stirredꢀatꢀ25ꢀ°Cꢀforꢀ4ꢀh,ꢀandꢀAgꢀNPsꢀwereꢀprecipitatedꢀimmedi‐
ately.ꢀTheꢀprecipitateꢀwasꢀfiltered,ꢀandꢀwashedꢀwithꢀ10ꢀmLꢀwa‐
terꢀandꢀthenꢀ10ꢀmLꢀanhydrousꢀethanolꢀforꢀ4ꢀtimes,ꢀandꢀdriedꢀ
forꢀ12ꢀhꢀatꢀ35ꢀ°Cꢀunderꢀvacuum.ꢀAgꢀNPꢀpowderꢀwasꢀpressedꢀ
intoꢀaꢀcoinꢀandꢀusedꢀasꢀtheꢀcathodeꢀforꢀelectrolysis.ꢀ
Fig.ꢀ2.ꢀCharacterizationꢀresultsꢀofꢀAgꢀNPs.ꢀFE‐SEMꢀpatternsꢀofꢀAgꢀNPsꢀ
withꢀmagnificationsꢀofꢀ5kꢀ(a),ꢀ20kꢀ(b),ꢀandꢀafterꢀreuseꢀforꢀ10ꢀtimesꢀ(c);ꢀ
(d):ꢀXRDꢀpatternsꢀofꢀAgꢀnanoparticlesꢀbeforeꢀ(d‐1)ꢀandꢀafterꢀreuseꢀforꢀ
10ꢀtimesꢀ(d‐2);ꢀFE‐SEMꢀpatternsꢀofꢀAgꢀNPsꢀwithꢀsmallerꢀparticleꢀsizeꢀ(e,ꢀ
f).ꢀ
Galvanostaticꢀelectrosynthesisꢀwasꢀperformedꢀusingꢀaꢀdirectꢀ
currentꢀ regulatedꢀ powerꢀ supplyꢀ (HY3002D,ꢀ HYelec®,ꢀ China).ꢀ
Theꢀproductꢀyieldꢀwasꢀdeterminedꢀbyꢀhighꢀperformanceꢀliquidꢀ
chromatographyꢀ (HPLC)ꢀ instrumentꢀ (DIONEXꢀ Ultimateꢀ 3000ꢀ
pump)ꢀequippedꢀwithꢀaꢀUVꢀ(RSꢀVariableꢀWavelength)ꢀdetector.ꢀ
TheꢀmicrostructureꢀandꢀmorphologyꢀofꢀAgꢀNPsꢀwereꢀanalyzedꢀ
usingꢀ aꢀ Hitachiꢀ S‐4800ꢀ fieldꢀ emissionꢀ Scanningꢀ Electronꢀ
Microscopeꢀ (FE‐SEM).ꢀ X‐rayꢀ diffractionꢀ (XRD)ꢀ patternsꢀ wereꢀ
recordedꢀbyꢀaꢀUltimaꢀIVꢀX‐rayꢀpowderꢀdiffractometerꢀusingꢀCuꢀ
anyꢀotherꢀsubstanceꢀsuchꢀasꢀsilverꢀoxideꢀwasꢀcontainedꢀinꢀthisꢀ
material.ꢀTheꢀFE‐SEMꢀpatternsꢀ(Fig.ꢀ2(a),ꢀ(b))ꢀofꢀtheꢀcompositeꢀ
revealedꢀthatꢀthisꢀAgꢀNPꢀelectrodeꢀhasꢀaꢀhierarchicalꢀstructureꢀ
composedꢀofꢀmetalꢀnanocrystallites.ꢀTheseꢀelementaryꢀparticlesꢀ
wereꢀgatheredꢀintoꢀparticlesꢀofꢀ60ꢀnmꢀandꢀaggregatedꢀfurtherꢀ
intoꢀaꢀmacroporousꢀsolid.ꢀ ꢀ
BesidesꢀtheꢀpreparationꢀandꢀcharacterizationꢀofꢀthisꢀAgꢀNPꢀ
coin,ꢀweꢀalsoꢀshowedꢀitsꢀapplicationꢀinꢀcatalysis.ꢀAsꢀweꢀmen‐
tionedꢀ above,ꢀ theꢀ Agꢀ NPꢀ powderꢀ wasꢀ compactedꢀ intoꢀ aꢀ coinꢀ
withꢀaꢀ2ꢀcmꢀdiameter,ꢀwhichꢀcanꢀbeꢀusedꢀdirectlyꢀasꢀtheꢀcathodeꢀ
forꢀtheꢀelectrocatalyticꢀcarboxylationꢀofꢀ1‐phenylethylꢀbromideꢀ
K
α 2
ꢀradiationꢀ(λꢀ=ꢀ0.15406ꢀnm).ꢀN ꢀadsorptionꢀwasꢀcarriedꢀoutꢀatꢀ
–196ꢀ °Cꢀ onꢀ aꢀ BELSORP‐MAXꢀ instrumentꢀ afterꢀ outgassingꢀ theꢀ
samplesꢀforꢀ10ꢀhꢀunderꢀvacuumꢀatꢀ300ꢀ°C.ꢀ
withꢀCO
.ꢀSinceꢀgalvanostaticꢀelectrolysisꢀisꢀoftenꢀsimplerꢀandꢀ
2
Theꢀresultingꢀmaterialꢀwasꢀcharacterizedꢀbyꢀmanyꢀmethods.ꢀ
Fig.ꢀ2(d)ꢀdisplaysꢀtheꢀXRDꢀpatternsꢀofꢀanꢀAgꢀNPsꢀcoin.ꢀTypicalꢀ
diffractionꢀ peaksꢀ ofꢀ theꢀ (111),ꢀ (200),ꢀ (220),ꢀ (311)ꢀ andꢀ (222)ꢀ
crystalꢀfacesꢀwereꢀobserved.ꢀItꢀisꢀalsoꢀnotableꢀthatꢀnoꢀtraceꢀofꢀ
preferableꢀ forꢀ largeꢀ scaleꢀ applications,ꢀ weꢀ thereforeꢀ investi‐
gatedꢀtheꢀefficiencyꢀofꢀtheꢀelectrocatalyticꢀcarboxylationꢀunderꢀ
galvanostaticꢀ conditions.ꢀ Aꢀ typicalꢀ galvanostaticꢀ electrolysisꢀ
wasꢀcarriedꢀoutꢀinꢀaꢀmixtureꢀofꢀ0.1ꢀmol/Lꢀ1‐phenylethylꢀbro‐
mideꢀ(1a),ꢀ0.1ꢀmol/Lꢀtetraethylammoniumꢀiodideꢀ(TEAI)ꢀinꢀ10ꢀ
mLꢀacetonitrileꢀ(MeCN)ꢀusingꢀanꢀundividedꢀglassꢀcellꢀwithꢀaꢀAgꢀ
NPꢀ cathodeꢀ andꢀ aꢀ sacrificialꢀ magnesiumꢀ (Mg)ꢀ anode.ꢀ Eachꢀ
measurementꢀwasꢀperformedꢀ3–4ꢀtimes.ꢀAfterꢀelectrolysis,ꢀtheꢀ
productsꢀwereꢀdetectedꢀquantitativelyꢀbyꢀHPLC,ꢀwhichꢀshowedꢀ
thatꢀ 2‐phenylpropionicꢀ acidꢀ (2a)ꢀ wasꢀ theꢀ mainꢀ product.ꢀ Theꢀ
influencesꢀofꢀelectricꢀchargeꢀ(Q),ꢀcurrentꢀdensity,ꢀandꢀtheꢀtem‐
peratureꢀ wereꢀ investigatedꢀ toꢀ optimizeꢀ theꢀ yieldꢀ ofꢀ 2a.ꢀ Theꢀ
resultsꢀofꢀtheꢀelectrolysisꢀareꢀsummarizedꢀinꢀTableꢀ1.ꢀ
Inꢀ anꢀ electrochemicalꢀ reaction,ꢀ theꢀ electricꢀ chargeꢀ passedꢀ
duringꢀelectrolysisꢀstronglyꢀinfluencedꢀtheꢀyieldꢀofꢀproductꢀ2aꢀ
(Tableꢀ 1,ꢀ entriesꢀ 1–4).ꢀ Theꢀ yieldꢀ increasedꢀ linearlyꢀ withꢀ theꢀ
Fig.ꢀ1.ꢀPreparationꢀofꢀAgꢀNPꢀelectrodeꢀandꢀelectrocatalyticꢀcarboxyla‐
chargeꢀ fromꢀ 1.5ꢀ toꢀ 2.5ꢀ F/mol.ꢀ However,ꢀ theꢀ yieldꢀ didꢀ notꢀ
increaseꢀfurtherꢀwhenꢀtheꢀchargeꢀincreasedꢀtoꢀ3.0ꢀF/molꢀ(Tableꢀ
tionꢀofꢀ1‐phenethylꢀbromideꢀwithꢀCO .ꢀ
2

996ꢀ
HengpanꢀYangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ994–998ꢀ
product?ꢀFurtherꢀexperimentsꢀwereꢀcarriedꢀoutꢀtoꢀtestꢀthis.ꢀWeꢀ
Tableꢀ1ꢀ
Electrocatalyticꢀcarboxylationꢀofꢀ1‐phenylethylꢀbromideꢀunderꢀdifferentꢀ
conditionsꢀ .ꢀ
preparedꢀAgꢀNPsꢀwithꢀ20ꢀnmꢀparticleꢀsizeꢀ(Fig.ꢀ2(e),ꢀ(f))ꢀusingꢀ
theꢀsameꢀmethodꢀasꢀtheꢀ60ꢀnmꢀAgꢀNPsꢀexceptꢀforꢀtheꢀadditionꢀ
ofꢀ polyethyleneꢀ glycolꢀ inꢀ theꢀ reductionꢀ solution.ꢀ Underꢀ theꢀ
sameꢀ conditionsꢀ asꢀ Tableꢀ 1,ꢀ entryꢀ 3,ꢀ 96%ꢀ yieldꢀ ofꢀ 2aꢀ wasꢀ
obtainedꢀatꢀtheꢀAgꢀNPꢀcathodeꢀwithꢀ20ꢀnmꢀparticleꢀsizeꢀ(Tableꢀ1ꢀ
entryꢀ14),ꢀwhichꢀwasꢀobviouslyꢀhigherꢀthanꢀthatꢀofꢀtheꢀAgꢀflakeꢀ
cathodeꢀbutꢀalmostꢀtheꢀsameꢀasꢀthatꢀofꢀAgꢀNPsꢀcathodeꢀwithꢀ60ꢀ
nmꢀparticleꢀsize.ꢀThisꢀdemonstratedꢀagainꢀthatꢀnano‐structureꢀ
silverꢀ wasꢀ beneficialꢀ toꢀ theꢀ electrocatalyticꢀ carboxylationꢀ ofꢀ
a
2
b
Entryꢀ
Qꢀ(F/mol)ꢀ Currentꢀdensityꢀ(mA/cm )ꢀ Tꢀ(°C)ꢀ Yieldꢀ ꢀ(%)
1
ꢀ
1.5ꢀ
2.0ꢀ
2.5ꢀ
3.0ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
2.5ꢀ
5ꢀ
5ꢀ
5ꢀ
5ꢀ
1ꢀ
3ꢀ
7ꢀ
9ꢀ
5ꢀ
5ꢀ
5ꢀ
5ꢀ
5ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
10ꢀ
20ꢀ
30ꢀ
ꢀ 0ꢀ
ꢀ 0ꢀ
72ꢀ
88ꢀ
98ꢀ
97ꢀ
73ꢀ
83ꢀ
89ꢀ
80ꢀ
92ꢀ
90ꢀ
87ꢀ
51ꢀ
96ꢀ
2
ꢀ
3
ꢀ
4
ꢀ
5
ꢀ
6
ꢀ
7
ꢀ
8
ꢀ
1
‐phenethylꢀbromideꢀwithꢀCO
2
.ꢀ
1
1
1
1
1
0ꢀ
1ꢀ
2ꢀ
3 ꢀ
4 ꢀ
Itꢀshouldꢀbeꢀnotedꢀthatꢀnoꢀotherꢀcatalystꢀwasꢀneededꢀinꢀourꢀ
synthesisꢀsystem.ꢀInꢀaddition,ꢀthisꢀAgꢀNPꢀcathodeꢀcanꢀbeꢀeasilyꢀ
recycledꢀ andꢀ cleanedꢀ afterꢀ anꢀ electrolysis.ꢀ Underꢀ theꢀ
electrolysisꢀconditionsꢀofꢀTableꢀ1,ꢀentryꢀ3,ꢀrepeatedꢀtestsꢀofꢀtheꢀ
electrocatalyticꢀcarboxylationꢀofꢀ1‐phenethylꢀbromideꢀwithꢀCO2ꢀ
wereꢀcarriedꢀoutꢀusingꢀtheꢀsameꢀAgꢀNPꢀcathode.ꢀAsꢀshownꢀinꢀ
Fig.ꢀ3,ꢀtheꢀyieldꢀofꢀ2aꢀwasꢀmaintainedꢀatꢀaroundꢀ94%ꢀevenꢀafterꢀ
ꢀ
c
ꢀd
aꢀElectrolysisꢀ wereꢀ carriedꢀ outꢀ inꢀ anꢀ undividedꢀ cell,ꢀ cathode:ꢀ Agꢀ NPs,ꢀ
anode:ꢀ Mg,ꢀ solvent:ꢀ 10ꢀ mLꢀ MeCN,ꢀ supportingꢀ electrolyte:ꢀ 0.1ꢀ mol/Lꢀ
bꢀ
TEAI,ꢀ substrateꢀ concentration:ꢀ 0.1ꢀ mol/L.ꢀ Determinedꢀ byꢀ HPLC.
cꢀ
dꢀ
Cathode:ꢀAgꢀflake.ꢀ Cathode:ꢀAgꢀNPsꢀ(20ꢀnm).ꢀ
10ꢀ runs,ꢀ revealingꢀ thatꢀ thisꢀ Agꢀ NPꢀ cathodeꢀ hasꢀ excellentꢀ
ꢀ
reusability.ꢀXRDꢀandꢀSEMꢀwereꢀusedꢀtoꢀfurtherꢀinvestigateꢀtheꢀ
stabilityꢀofꢀtheꢀAgꢀNPꢀelectrode.ꢀAccordingꢀtoꢀtheꢀXRDꢀpatterns,ꢀ
theꢀcompositionꢀandꢀcrystalꢀformꢀofꢀtheꢀAgꢀNPsꢀdidꢀnotꢀchangeꢀ
beforeꢀandꢀafterꢀelectrolysisꢀ(Fig.ꢀ2(d)).ꢀMoreover,ꢀitꢀretainedꢀ
itsꢀporousꢀstructuresꢀandꢀhadꢀtheꢀsameꢀparticleꢀsizeꢀ(Fig.ꢀ2(c)).ꢀ
Inꢀotherꢀwords,ꢀtheꢀAgꢀNPsꢀelectrodeꢀhasꢀexcellentꢀstabilityꢀandꢀ
reusability,ꢀ andꢀ retainedꢀ itsꢀ catalyticꢀ activityꢀ afterꢀ atꢀ leastꢀ 10ꢀ
timesꢀreuse.ꢀ
1
,ꢀentryꢀ4),ꢀindicatingꢀthatꢀ1aꢀwasꢀalreadyꢀconsumedꢀentirelyꢀ
whenꢀ2.5ꢀF/molꢀelectricꢀchargeꢀwasꢀpassed.ꢀAsꢀforꢀtheꢀinfluenceꢀ
ofꢀ theꢀ currentꢀ density,ꢀ theꢀ yieldꢀ ofꢀ 2aꢀ improvedꢀ withꢀ theꢀ
currentꢀ densityꢀ fromꢀ 1ꢀ toꢀ 9ꢀ mA/cm ,ꢀ reachingꢀ aꢀ maximumꢀ
2
2
(98%)ꢀatꢀ5ꢀmA/cm ꢀ(Tableꢀ1,ꢀentriesꢀ3,ꢀ5–8).ꢀBothꢀlowꢀandꢀhighꢀ
currentꢀdensitiesꢀledꢀtoꢀlowerꢀyields.ꢀTheꢀreactionꢀtemperatureꢀ
wasꢀ alsoꢀ aꢀ crucialꢀ factor,ꢀ whichꢀ influencedꢀ theꢀ overpotentialꢀ
andꢀreactionꢀrateꢀofꢀtheꢀelectrolysis.ꢀTheꢀhighestꢀyieldꢀofꢀ2aꢀwasꢀ
obtainedꢀ atꢀ0ꢀ °C,ꢀaꢀ relativelyꢀlowꢀtemperature.ꢀIncreasingꢀtheꢀ
temperatureꢀfromꢀ0ꢀtoꢀ30ꢀ°Cꢀdidꢀnotꢀincreaseꢀtheꢀyieldꢀofꢀ2a.ꢀOnꢀ
theꢀ contrary,ꢀ theꢀ 2aꢀ yieldꢀ decreasedꢀ fromꢀ 98%ꢀ toꢀ 87%.ꢀ Atꢀ aꢀ
Encouragedꢀ byꢀ excellentꢀ resultsꢀ obtainedꢀ withꢀ
1
‐phenylethylꢀbromideꢀ(1a),ꢀtheꢀuseꢀofꢀdifferentꢀsubstratesꢀwasꢀ
furtherꢀstudied.ꢀUsingꢀtheꢀreactionꢀconditionsꢀofꢀTableꢀ1,ꢀentryꢀ
,ꢀ aꢀ wideꢀ rangeꢀ ofꢀ substitutedꢀ bromidesꢀ withꢀ bothꢀ
3
lowerꢀtemperature,ꢀmoreꢀCO ꢀwasꢀdissolvedꢀinꢀMeCN,ꢀandꢀCO2ꢀ
2
electron‐withdrawingꢀ andꢀ electron‐donatingꢀ groupsꢀ wereꢀ
testedꢀ forꢀ electrocatalyticꢀ carboxylation.ꢀ Theꢀ correspondingꢀ
benzoicꢀacidsꢀwithꢀmoderateꢀtoꢀgoodꢀyieldsꢀwereꢀobtained.ꢀAsꢀ
isꢀobviousꢀfromꢀtheꢀresultsꢀsummarizedꢀinꢀTableꢀ2,ꢀtheꢀAgꢀNPꢀ
cathodeꢀcanꢀbeꢀappliedꢀtoꢀaꢀwideꢀrangeꢀofꢀsubstrates.ꢀExceptꢀforꢀ
bromides,ꢀ theꢀ Agꢀ NPꢀ cathodeꢀ wasꢀ alsoꢀ effectiveꢀ forꢀ theꢀ
carboxylationꢀ ofꢀ 1‐phenylethylꢀ chloride,ꢀ andꢀ 86%ꢀ yieldꢀ ofꢀ
isꢀ theꢀ keyꢀ reagentꢀ inꢀ thisꢀ reaction,ꢀ whichꢀ couldꢀ explainꢀ thisꢀ
trendꢀ [19].ꢀ Althoughꢀ thereꢀ wasꢀ aꢀ slightꢀ decline,ꢀ atꢀ leastꢀ 90%ꢀ
yieldꢀ ofꢀ 2aꢀ couldꢀ beꢀ achievedꢀ atꢀ 20ꢀ °C,ꢀ whichꢀ wasꢀ roomꢀ
temperature.ꢀHence,ꢀourꢀAgꢀNPꢀelectrodeꢀgeneratedꢀveryꢀgoodꢀ
resultsꢀ forꢀ theꢀ electrocatalyticꢀ carboxylationꢀ ofꢀ 1‐phenethylꢀ
bromideꢀ withꢀ CO
withoutꢀtheꢀutilizationꢀofꢀhighꢀCO
2
ꢀ underꢀ veryꢀ mildꢀ conditions.ꢀ Thisꢀ wasꢀ
2
ꢀpressureꢀorꢀtemperature.ꢀ ꢀ
UsingꢀtheꢀoptimizedꢀconditionsꢀinꢀTableꢀ1,ꢀentryꢀ3,ꢀdifferentꢀ
cathodesꢀwereꢀalsoꢀstudiedꢀtoꢀshowꢀtheꢀsuperiorityꢀofꢀourꢀAgꢀ
NPꢀcathode.ꢀUsingꢀAgꢀflakeꢀasꢀcathodeꢀ(Tableꢀ1ꢀentryꢀ13),ꢀonlyꢀ
100
51%ꢀ yieldꢀ ofꢀ 2aꢀwasꢀobtained,ꢀwhichꢀ wasꢀ significantlyꢀlowerꢀ
80
thanꢀtheꢀ98%ꢀyieldꢀwithꢀtheꢀAgꢀNPꢀcathode,ꢀindicatingꢀthatꢀourꢀ
AgꢀNPꢀcathodeꢀwasꢀmuchꢀmoreꢀeffectiveꢀforꢀtheꢀelectrocatalyticꢀ
60
40
20
0
carboxylationꢀofꢀ1‐phenethylꢀbromideꢀwithꢀCO
Agꢀflakeꢀcathode.ꢀThisꢀsuperiorityꢀcanꢀbeꢀattributedꢀtoꢀtheꢀlargeꢀ
specificꢀsurfaceꢀareaꢀofꢀAgꢀNPs.ꢀAccordingꢀtoꢀtheꢀN ꢀadsorptionꢀ
2
ꢀthanꢀaꢀcommonꢀ
2
isotherm,ꢀtheꢀAgꢀNPꢀcoinꢀhasꢀanꢀaverageꢀspecificꢀsurfaceꢀareaꢀofꢀ
2
8
.7ꢀm /g.ꢀSinceꢀ2ꢀgꢀAgꢀNPsꢀpowderꢀwasꢀcompactedꢀintoꢀaꢀ2ꢀcmꢀ
diameterꢀcoin,ꢀthisꢀgaveꢀthisꢀAgꢀNPꢀcathodeꢀanꢀactualꢀsurfaceꢀ
2
areaꢀ ofꢀ 17.4ꢀ m .ꢀ Hence,ꢀ theꢀ realꢀ surfaceꢀ areaꢀ ofꢀ theꢀ Agꢀ NPꢀ
4
cathodeꢀisꢀ5.5ꢀ×ꢀ10 ꢀtimesꢀlargerꢀthanꢀthatꢀofꢀaꢀcommonꢀAgꢀflakeꢀ
1
2
3
4
5
6
7
8
9
10
cathode,ꢀwhichꢀwouldꢀprovideꢀmoreꢀactiveꢀsitesꢀandꢀaccelerateꢀ
theꢀ reactionꢀ rate.ꢀ Sinceꢀ Agꢀ NPsꢀ wereꢀ moreꢀ efficientꢀ thanꢀ aꢀ
commonꢀAgꢀflakeꢀcathodeꢀbecauseꢀofꢀitsꢀnano‐structure,ꢀcanꢀAgꢀ
NPsꢀwithꢀsmallerꢀparticleꢀsizeꢀleadꢀtoꢀanꢀevenꢀhigherꢀyieldꢀofꢀ
Recycle times
Fig.ꢀ3.ꢀReuseꢀofꢀAgꢀNPsꢀcathode.ꢀReactionꢀconditionsꢀareꢀtheꢀsameꢀasꢀ
Tableꢀ1,ꢀentryꢀ3.ꢀ

ꢀ
HengpanꢀYangꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ37ꢀ(2016)ꢀ994–998ꢀ
Referencesꢀ
997ꢀ
Tableꢀ2ꢀ
Electrocatalyticꢀ carboxylationꢀ ofꢀ differentꢀ substratesꢀ withꢀ theꢀ Agꢀ NPꢀ
a
cathodeꢀ .ꢀ
[1] T.ꢀ Sakakura,ꢀ J.ꢀ C.ꢀ Choi,ꢀ H.ꢀ Yasuda,ꢀ Chem.ꢀ Rev.,ꢀ 2007,ꢀ 107,ꢀ
2365–2387.ꢀ
[2]ꢀ C.ꢀ A.ꢀ Huff,ꢀ M.ꢀ S.ꢀ Sanford,ꢀ J.ꢀ Am.ꢀ Chem.ꢀ Soc.,ꢀ 2011,ꢀ 133,ꢀ
ꢀb
Entryꢀ
Substrateꢀ
Productꢀ
COOH
Yield ꢀ(%)
Br
1
8122–18125.ꢀ
1
ꢀ
ꢀ ꢀ ꢀ 1aꢀ
ꢀ ꢀ 2aꢀ
98ꢀ
[
[
[
[
[
[
3]ꢀ Z.ꢀ F.ꢀ Zhang,ꢀ S.ꢀ Q.ꢀ Hu,ꢀ J.ꢀ L.ꢀ Song,ꢀ W.ꢀ J.ꢀ Li,ꢀ G.ꢀ Y.ꢀ Yang,ꢀ B.ꢀ X.ꢀ Han,ꢀ
ChemSusChem,ꢀ2009,ꢀ2,ꢀ234–238.ꢀ
4]ꢀ S.ꢀG.ꢀLiang,ꢀH.ꢀZ.ꢀLiu,ꢀT.ꢀJiang,ꢀJ.ꢀL.ꢀSong,ꢀG.ꢀY.ꢀYang,ꢀB.ꢀX.ꢀHan,ꢀChem.ꢀ
Commun.,ꢀ2011,ꢀ47,ꢀ2131–2133.ꢀ
5]ꢀ F.ꢀShi,ꢀY.ꢀQ.ꢀDeng,ꢀT.ꢀL.ꢀSiMa,ꢀJ.ꢀJ.ꢀPeng,ꢀY.ꢀL.ꢀGu,ꢀB.ꢀT.ꢀQiao,ꢀAngew.ꢀ
Chem.ꢀInt.ꢀEd.,ꢀ2003,ꢀ42,ꢀ3257–3260.ꢀ
6]ꢀ B.ꢀYu,ꢀH.ꢀY.ꢀZhang,ꢀY.ꢀF.ꢀZhao,ꢀS.ꢀChen,ꢀJ.ꢀL.ꢀXu,ꢀC.ꢀL.ꢀHuang,ꢀZ.ꢀM.ꢀLiu,ꢀ
GreenꢀChem.,ꢀ2013,ꢀ15,ꢀ95–99.ꢀ
7]ꢀ O.ꢀJacquet,ꢀC.ꢀDasꢀNevesꢀGomes,ꢀM.ꢀEphritikhine,ꢀT.ꢀCantat,ꢀChem‐
CatChem,ꢀ2013,ꢀ5,ꢀ117–120.ꢀ
8]ꢀ M.ꢀ North,ꢀ R.ꢀ Pasquale,ꢀ C.ꢀ Young,ꢀ Greenꢀ Chem.,ꢀ 2010,ꢀ 12,ꢀ
Br
COOH
2ꢀ
ꢀ ꢀ 1bꢀ
ꢀ 2bꢀ
88ꢀ
73ꢀ
Br
COOH
3ꢀ
ꢀ ꢀ ꢀ ꢀ 1cꢀ
ꢀ ꢀ ꢀ 2cꢀ
COOH
Br ꢀ ꢀ 1dꢀ
COOH
4ꢀ
COOH ꢀ 2dꢀ
67ꢀ
78ꢀ
81ꢀ
Br
COOH
5ꢀ
ꢀ 1eꢀ
ꢀ 1fꢀ
2eꢀ
1514–1539.ꢀ
Br
COOH
[9]ꢀ A.ꢀA.ꢀIsse,ꢀA.ꢀD.ꢀGiusti,ꢀA.ꢀGennaro,ꢀL.ꢀFalciola,ꢀP.ꢀR.ꢀMussini,ꢀElec‐
trochim.ꢀActa,ꢀ2006,ꢀ51,ꢀ4956–4964.ꢀ
10]ꢀ P.ꢀL.ꢀFabre,ꢀO.ꢀReynes,ꢀElectrochem.ꢀCommun.,ꢀ2010,ꢀ12,ꢀ1360–1362.ꢀ
11]ꢀ A.ꢀGennaro,ꢀA.ꢀA.ꢀIsse,ꢀF.ꢀMaran,ꢀJ.ꢀElectroanal.ꢀChem.,ꢀ2001,ꢀ507,ꢀ
6ꢀ
ꢀ ꢀ 2fꢀ
[
[
Cl
COOH
1
24–134.ꢀ
12]ꢀ J.ꢀDamodar,ꢀS.ꢀR.ꢀK.ꢀMohan,ꢀS.ꢀR.ꢀJ.ꢀReddy,ꢀElectrochem.ꢀCommun.,ꢀ
001,ꢀ3,ꢀ762–766.ꢀ
7ꢀ
ꢀ ꢀ ꢀ 1gꢀ
ꢀ ꢀ ꢀ 2gꢀ
86ꢀ
[
2
aꢀ
Electrolysisꢀ wereꢀ carriedꢀ outꢀ underꢀ theꢀ sameꢀ conditionsꢀ asꢀ Tableꢀ 1,ꢀ
[13]ꢀ L.ꢀX.ꢀWu,ꢀH.ꢀWang,ꢀY.ꢀXiao,ꢀZ.ꢀY.ꢀTu,ꢀB.ꢀB.ꢀDing,ꢀJ.ꢀX.ꢀLu,ꢀElectrochem.ꢀ
Commun.,ꢀ2012,ꢀ25,ꢀ116–118.ꢀ
14]ꢀ Y.ꢀXiao,ꢀB.ꢀL.ꢀChen,ꢀH.ꢀP.ꢀYang,ꢀH.ꢀWang,ꢀJ.ꢀX.ꢀLu,ꢀElectrochem.ꢀCom‐
mun.,ꢀ2014,ꢀ43,ꢀ71–74.ꢀ
bꢀ
entryꢀ3.ꢀ DeterminedꢀbyꢀHPLC.ꢀ
ꢀ
[
2
‐phenylpropionicꢀacidꢀwasꢀobtainedꢀusingꢀtheꢀsameꢀreactionꢀ
[
15]ꢀ A.ꢀA.ꢀIsse,ꢀC.ꢀDurante,ꢀA.ꢀGennaro,ꢀElectrochem.ꢀCommun.,ꢀ2011,ꢀ13,ꢀ
conditionꢀasꢀ1‐phenylethylꢀbromideꢀ(Tableꢀ2,ꢀentryꢀ7).ꢀ
810–813.ꢀ
Inꢀ conclusion,ꢀ aꢀ compactedꢀ Agꢀ NPꢀ cathodeꢀ wasꢀ preparedꢀ
usingꢀaꢀsimpleꢀmethodꢀwithoutꢀanyꢀsupportꢀorꢀcarrier.ꢀThisꢀwasꢀ
effectiveꢀ forꢀ theꢀ electrocatalyticꢀ carboxylationꢀ ofꢀ 1‐phenethylꢀ
[
[
16]ꢀ A.ꢀA.ꢀIsse,ꢀA.ꢀGennaro,ꢀChem.ꢀCommun.,ꢀ2002,ꢀ2798–2799.ꢀ
17]ꢀ B.ꢀL.ꢀChen,ꢀH.ꢀW.ꢀZhu,ꢀY.ꢀXiao,ꢀQ.ꢀL.ꢀSun,ꢀH.ꢀWang,ꢀJ.ꢀX.ꢀLu,ꢀElectro‐
chem.ꢀCommun.,ꢀ2014,ꢀ42,ꢀ55–59.ꢀ
bromideꢀ withꢀ CO
2
.ꢀ Underꢀ optimizedꢀ conditions,ꢀ
[
18]ꢀ H.ꢀP.ꢀYang,ꢀY.ꢀN.ꢀYue,ꢀQ.ꢀL.ꢀSun,ꢀQ.ꢀFeng,ꢀH.ꢀWang,ꢀJ.ꢀX.ꢀLu,ꢀChem.ꢀ
2‐phenylpropionicꢀacidꢀwithꢀ98%ꢀyieldꢀwasꢀobtained.ꢀModerateꢀ
Commun.,ꢀ2015,ꢀ51,ꢀ12216–12219.ꢀ
toꢀ goodꢀ yieldsꢀ ofꢀ benzoicꢀ acidsꢀ wereꢀ achievedꢀ withꢀ otherꢀ
substrates.ꢀ Thisꢀ Agꢀ NPꢀ cathodeꢀ hasꢀ remarkableꢀ stabilityꢀ andꢀ
reusability,ꢀshownꢀbyꢀthatꢀtheꢀyieldꢀofꢀ2‐phenylpropionicꢀacidꢀ
didꢀ notꢀ decreaseꢀ significantlyꢀ afterꢀ atꢀ leastꢀ 10ꢀ timesꢀ reuse.ꢀ
Consideringꢀ itsꢀ easyꢀ preparation,ꢀ highꢀ effectivenessꢀ andꢀ
excellentꢀ reusability,ꢀ thisꢀ Agꢀ NPꢀ cathodeꢀ hasꢀ potentialꢀ forꢀ
practicalꢀapplication.ꢀ
[19]ꢀ A.ꢀGennaro,ꢀA.ꢀA.ꢀIsse,ꢀE.ꢀVianello,ꢀJ.ꢀElectroanal.ꢀChem.,ꢀ1990,ꢀ289,ꢀ
203–215.ꢀ
Pageꢀnumbersꢀreferꢀtoꢀtheꢀcontentsꢀinꢀtheꢀprintꢀversion,ꢀwhichꢀincludeꢀ
bothꢀtheꢀEnglishꢀversionꢀandꢀextendedꢀChineseꢀabstractꢀofꢀtheꢀpaper.ꢀTheꢀ
onlineꢀversionꢀonlyꢀhasꢀtheꢀEnglishꢀversion.ꢀTheꢀpagesꢀwithꢀtheꢀextendedꢀ
Chineseꢀabstractꢀareꢀonlyꢀavailableꢀinꢀtheꢀprintꢀversion.ꢀ
GraphicalꢀAbstractꢀ
Chin.ꢀJ.ꢀCatal.,ꢀ2016,ꢀ37:ꢀ994–998ꢀ ꢀ ꢀ doi:ꢀ10.1016/S1872‐2067(15)61075‐0
9
8% yield ！
Cathodeꢀmadeꢀofꢀcompactedꢀsilverꢀnanoparticlesꢀforꢀelectrocatalyticꢀ
carboxylationꢀofꢀ1‐phenethylꢀbromideꢀwithꢀCO ꢀ
2
Excellent reusability！
HengpanꢀYang,ꢀLaxiaꢀWu,ꢀHuanꢀWangꢀ*,ꢀJiaxingꢀLuꢀ*ꢀ
EastꢀChinaꢀNormalꢀUniversity;ꢀAnqingꢀNormalꢀUniversityꢀ
+
CO2
AꢀcathodeꢀmadeꢀofꢀcompactedꢀAgꢀnanoparticlesꢀwasꢀpreparedꢀwithꢀaꢀsimpleꢀ
methodꢀandꢀusedꢀforꢀtheꢀelectrocatalyticꢀcarboxylationꢀofꢀ1‐phenethylꢀbro‐
+e-
e-
2
mideꢀwithꢀCO .ꢀItꢀhasꢀexcellentꢀefficiency,ꢀhighꢀstabilityꢀandꢀremarkableꢀre‐
usabilityꢀandꢀwasꢀactiveꢀunderꢀveryꢀmildꢀconditions.ꢀ
Ag NPs