不同负载方法制备镍金属有序介孔氧化铝催化剂的结构及性能

采用原位合成技术制备出负载镍金属介孔氧化铝催化剂，同时采用过量浸渍法在已合成的有序介孔氧化铝和普通氧化铝上负载镍金属。采用BET、TEM、XRD、XPS、TPR、ICP-OES多种测试技术对3种催化剂结构特征、镍金属与载体的相互作用进行了表征，同时采用甲烷化反应验证3种催化剂的催化性能。实验结果表明, 两种方法制备的负载镍金属介孔氧化铝催化剂相对于普通氧化铝结构稳定、孔径分布窄。原位合成的负载镍金属催化剂负载量大，镍金属与载体的相互作用力强。但金属的价态为难还原的偏铝酸镍，对甲烷化反应催化性能不高。过量浸渍法制备有序介孔氧化铝催化剂孔结构稳定，镍分散性好，价态以易还原的氧化镍为主，其催化性能要高于普通氧化铝，表明合成的有序介孔氧化铝在催化领域将具有重要的应用价值。

Structure and properties of nickel-containing catalysts supported on organized mesoporous alumina prepared by different supporting methods

A nickel catalyst supported on mesoporous alumina(Ni-Al2O3) has been prepared by an in situ synthesis method.For comparison purposes,nickel has also been supported on mesoporous alumina and ordinary alumina by the impregnation method.The structural properties and nature of the interaction between nickel and the carriers have been investigated by BET,TEM,XRD,XPS,TPR,and ICP-OES.The activities of the different catalysts have been compared using methanation of carbon monoxide as the probe reaction.The results show that catalysts based on nickel supported on mesoporous alumina synthesized by either method have a more stable structure and narrower pore size distribution compared with those involving nickel supported on ordinary alumina.Although the nickel-containing catalyst synthesized by the in situ method exhibited much higher nickel loadings than those produced by the impregnation method,the nickel was in the form of nickel aluminate which is not readily reduced and results in a low activity for the methanation of carbon monoxide.The nickel-containing catalyst supported on mesoporous alumina synthesized by the impregnation method has a stable structure and high degree of dispersion of nickel.Furthermore,the nickel was in the form of nickel oxide which is easily reduced.The synthetic method involves simple technology and low cost and the new catalyst has potential importance in catalysis.