铈钼氧化物表面氧性质和催化性能

在甲苯选择性氧化制苯甲醛反应中，Mo基氧化物是一类重要的催化剂1]．通常的认识是反应物与催化剂表面晶格氧作用，并通过催化剂本身的还原和氧化的循环过程促使反应进行。生成产物．因此，催化剂表面不同氧物种的热脱附性能应与催化反应性能密切相关．对于Ce-Mo氧化物的TPD-MS研究，尚未见文献报导．为了能获得该方面的信息，本文应用程序升温脱附-质谱检测（TP-MS）联用技术，对Ce-Mo氧化物样品进行了表面氧TPD谱测定和动力学参量等计算，并试图与其催化性能进行关联．1实验部分1．1样品的制备和表征分别将一定质量的硝酸铈铵和仲…

Natures of Oxygen Species on the Surfaces of Ce-Mo Oxides and Catalytic Activities for the Selective Oxidation of Toluene

A series of Ce-Mo oxide catalysts with different Ce/Mo atomic ratio were prepared and applied to selective oxidation of toluene to benzaldehyde.The structures and properties of the surfaces of catalysts were characterized by XRD,TPR and DR-UVS.The natures of oxygen species on the surfaces of these samples were studied by using temperature programmed desorption mass spectrography(TPD-MS).The results showed that the oxygen species of multiple adsorption existed on the sample surface.And in the range of desorption temperature <900℃ ,for the Ce-Mo samples,not only the desorption peaks of O- species on surfaces of samples be discoved,but also the O2- species appeared.As the content of Ce in Ce-Mo oxides was changed,the activation energy of oxygen desorption(Ed) also changed.The Ed value of sample 3(Ce/Mo="1/1)" is the lowest and its selectivity of benzaldehyde in toluene oxidation is the highest.Thus,a parallel relation between the Ed value and the selectivity for benzaldehyde existed in these Ce-Mo oxides.