Ce改性Ni/MnO_(x)催化剂用于甲烷干重整的研究

Ce-modified Ni/MnO_(x) catalysts for methane dry reforming

采用氧化还原沉淀法制备了系列xCe(100-x)MnO_(x)(简记为xC(100-x)M,x分别为0、10%、30%、50%、80%、100%)复合氧化物,通过浸渍法负载Ni制备Ni/xC(100-x)M系列催化剂。以CH_(4)干重整反应制合成气为模型反应,研究Ce与Mn质量比对Ni/CeMnO_(x)催化剂活性的影响。结果表明,在Ni/MnO_(x)催化剂中引入Ce助剂,提高了催化剂的比表面积和表面碱性位点数量,改善了催化剂的还原能力。在系列Ni/CeMnO_(x)催化剂中,Ce与Mn质量比对反应活性有着显著的影响,Ce质量分数的增加有利于提高CH_(4)和CO_(2)转化率,在反应温度为700℃和V(CH_(4))/V(CO_(2))=1∶1的条件下,Ni80C20M催化剂的CH_(4)和CO_(2)转化率相对较高,CH_(4)转化率为73.90%,CO_(2)转化率为79.38%。

xCe(100-x)MnO_(x)(x=0%,10%,30%,50%,80%,and 100%,respectively),a series of composite oxides,are prepared via the redox precipitation method.Ni/CeMnO_(x) series catalysts are then prepared by loading Ni onto xCe(100-x)MnO_(x) through the impregnation method.The dry reforming reaction of CH_(4) to syngas is served as a model reaction to study the influence of the mass ratio of Ce/Mn on the activity of Ni/CeMnO_(x) catalysts.It is found that the addition of Ce additives into Ni/MnO_(x) catalysts increases the specific surface area and the number of surface basic sites,as well as improves the reduction ability of the catalysts.Additionally,Ce addition improves the catalystsreduction ability.In the Ni/CeMnO_(x) series catalysts,the mass ratio of Ce to Mn significantly impacts the reaction activity.The higher Ce mass fraction is beneficial for enhancing the conversion rates of CH_(4) and CO_(2).Notably,at 700℃and V(CH_(4))/V(CO_(2))=1∶1,the conversion rates of CH_(4) and CO_(2) over Ni80Ce20Mn catalyst are relatively high,73.90%and 79.38%,respectively.