载体焙烧温度对Co-Mo/MgO-Al2O3变换催化剂性能的影响  

Effect of Calcination Temperature of Support on the Performance of Co-Mo/MgO-Al_2O_3 Water-Gas Shift Catalyst

作　　者：连奕新[1] 王会芳[1] 方维平[1] 杨意泉[1] 

机构地区：[1]厦门大学化学化工学院化学系、醇醚酯清洁生产国家工程实验室,福建厦门361005

出　　处：《催化学报》2009年第6期549-554,共6页

基　　金：福建省科技厅工业科技重点项目(2007H0066);厦门市企业创新基金(3502Z31082)

摘　　要：通过X射线衍射、N2吸附-脱附、程序升温脱附、程序升温还原和电子顺磁共振方法研究了焙烧温度对MgO-Al2O3载体物化结构和Co-Mo/MgO-Al2O3变换催化剂性能的影响.结果表明,在600～800oC范围内焙烧的复合氧化物以MgAl2O4-xMgO-yAl2O3无定形形式存在,载体表面存在较多的中强酸-碱位,相应的负载催化剂具有较高的水煤气变换活性.在氧化态催化剂中存在较多八面体结构的Mo物种,而硫化态催化剂中含有较多氧硫包围的Mo物种.这些钼物种与催化剂的活性紧密相关.The effect of calcination temperature of the MgO-Al2O3 mixed oxide support on the physicochemical properties of the support and the performance of the Co-Mo-based water-gas shift catalyst was studied by means of X-ray diffraction, N2 adsorption-desorption, temperature-programmed desorption, temperature-programmed reduction, and electron paramagnetic resonance. The activity testing results showed that the catalysts with the mixed oxide supports calcined at 600-800 ℃ exhibited high activity for the reaction. The physicochemical characterization results indicated that MgO-Al2O3 mixed oxide supports calcined at 600-800℃existed as amorphous compound MgAl2O4- xMgO-yAl2O3, on which more middle strength acid-base sites were formed. For the Co-Mo/MgO-Al2O3 catalysts in oxidation state, more octahedral Mo species were found, while more oxysulfo-Mo^5＋ species were detected on the sulfurized catalysts. These species were closely related to the catalytic activity.

关 键 词：氧化镁 氧化铝 尖晶石 钴钼基催化剂 水煤气变换 

分 类 号：O643.36[理学—物理化学]