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考察了一系列在不同温度下制备的Cu/γ-A12O3催化剂对苯催化燃烧的性能,并利用X-射线粉末衍射(XRD)、X-射线光电子能谱(XPS)、程序升温还原(TPR)对催化剂进行了表征.结果表明:低于单层分散的CuO具有可在低温还原的特性.在低于单层分散阈值的范围内,随着CuO负载量的增加催化剂活性加.超过单层分散阈值,催化剂活性反而下降.单层分散的CuO物种是非稳态的.随着焙烧温度的增加,分散阈值也会发生增加,这可能是Cu物种扩散至载体晶相引起的,在这种中情况下,催化剂活性下降.
A series of Cu / γ-A12O3 catalysts prepared at different temperatures were investigated for catalytic combustion of benzene. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) The results show that CuO with lower than monolayer dispersion has the characteristic of being able to reduce at low temperature.Under the monolayer dispersion threshold, the catalyst activity increases with the increase of CuO loading, Threshold, but the activity of catalyst decreases instead.The monolayer dispersion of CuO species is unstable.With the increase of calcination temperature, the dispersion threshold also increases, which may be caused by the diffusion of Cu species to the carrier phase, Under the catalyst activity decreased.