CO优先氧化反应MnCu/Ce催化剂的制备及性能

Preparation and properties of MnCu/Ce catalyst for CO preferential oxidation reaction

采用共浸渍法制备较低Cu含量的MnCu/Ce催化剂,通过XRD、BET、H_(2)-TPR、XPS和CO_(2)-TPD等表征手段对催化剂进行表征,考察催化剂焙烧温度对催化剂结构、性质及其在含有CO_(2)的富氢气氛下对CO优先氧化性能的影响。结果表明,MnCu/Ce催化剂均有Cu/Mn-O-Ce固溶体形成,其中,在焙烧温度600℃制备的催化剂中,Mn与Cu、Ce之间相互作用较强,形成较多三元氧化物固溶体,氧空位/Ce^(3+)含量高,具备良好的CO-Prox活性。此外,对反应条件的考察发现,添加不同分压Ar对催化剂的CO-Prox活性影响较小,气体空速和氧过量系数对催化剂活性影响较大,且反应原料气中CO_(2)的存在对CO-Prox反应有负面影响。氧过量系数为1.2、空速范围为20266-30400 mL/(g·h)时,CO转化率最高,达到94.7%。

The MnCu/Ce catalyst with a lower Cu content was prepared by co-impregnation method,and then was characterized by XRD,BET,H_(2)-TPR,XPS and CO_(2)-TPD.The effects of calcination temperature on the structure and properties of the catalyst and the preferential oxidation of CO in a hydrogen-rich atmosphere containing CO_(2) were investigated.The results indicated that Cu/Mn-O-Ce solid solution was formed in all MnCu/Ce catalysts.Of theses sample,the one calcined at 600℃ had strong interaction among Mn,Cu and Ce,formed more ternary oxide solid solution with more oxygen vacancies/Ce^(3+),and revealed good CO-Prox activity.In addition,it was found that the addition of different percentage of Ar had little effects on the CO-Prox activity of the catalyst,while the space velocity and oxygen excess coefficient had great effects on the catalytic performance,and the presence of CO_(2) in the reaction feedstock gas had a negative effect on the CO-Prox reaction.At an oxygen excess coefficient of 1.2 and the space velocity of 20266−30400 mL/(g·h),the highest CO conversion rate reached 94.7%.