促进钾盐为水煤气变换反应的钌_交流催化剂(4)

co变换催化剂

Table2

ResultsofN2adsorptionmeasurementsofthecatalysts.CatalystACRu/AC

Ru-K2CO3/AC

Surfacearea(cm2/g)792564558

Porediameter(nm)2.82.83.0

Porevolume(cm3/g)0.5480.3880.384

asprecursor[25].ComparedwiththeTPRpro leoftheRu/ACcat-alyst,the rstreductionpeakofallthepotassiumsaltsdopedRu/ACcatalystsdividedintotwopeaksandshiftedtolowertempera-ture,thesecondreductionpeakwasmuchweaker.Forinstance,thelowtemperaturereductionpeakofRu-K2CO3/ACappearedat93°Cand201°C,whilethosewereobservedat122°Cand247°CforRu-KOAc/AC,100°Cand201°CforRu-KOH/AC,respec-tively.TheH2consumptionofthecatalystsduringH2-TPRexperi-mentwascalculatedbystandardH2pulseexperiment,andtheresultsareshowninTable3.Itonlyneed1mmolH2for50mg2%Ru/ACcatalystduringH2-TPRexperimentifRuwastotallyoxi-dizedintoRuO2.Obviously,theH2consumptionduringH2-TPRexperimentwasmuchlowerthanthecalculateddata,whichindi-catedthatRuwaspartiallyoxidizedduringstorage.TheH2con-sumptionofRu-K2CO3/ACandRu-KOAc/ACwaslargerthanRu-KOH/AC,andallofthemwerelargerthanRu/AC.TheseresultsindicatedthatRuwasfurtheroxidizedafterdopingpotassium,andtheoxidationdegreeofpotassiumsalt(K2CO3,Ru-KOAc)dop-ingcatalystwaslargerthanKOHdopingcatalyst.

TheinteractionbetweentheRuOxnanoparticlesandactivecar-bonwascomparativelyweakandhigherdispersiondegreeofRuparticleleadtolowerreductiontemperature[26].However,iftheactivecarbonwasfunctionalizedbythetreatment

with

Table3

ThepeakpositionandH2consumptioncalculatedfromH2-TPRexperiment.CatalystsRu/AC

Ru-KOH/ACRu-K2CO3/ACRu-KOAc/AC

T(K)Peak–10093122

1

T(K)Peak270201201247

2

T(K)Peak330341339350

3

H2consumption(lmol)27313536

400°Cwithtwomaximumpeaksat270and330°C,respectively.Thesesignalscanbeassignedtothereductionofwell-dispersedRuOxoxidespecies,andsimilarresultswerealsoobservedintheTPRpro lesofRu/c-Al2O3,inwhichalsoRu(NO)(NO3)3wasused