纳米Ni-Al2O3体相催化剂的TEM和TPR表征及反应机理探讨

摘要

Using the Super-Solubilization Nanometer Self-Assembly method, bulk Ni-Al2 O3 catalyst is prepared with nickelnitratehexahydrate as the precursor and urea as precipitation agent,the mixture of the surfactant-gather isobutylene maleic acid triethanolamine esters and petroleum hydrocarbon-150SN as template agent.The Ni-Al2 O3 catalysts were characterized by TEM and TPR,and reaction mechanism of precipitation was studied.The results indicate that nanosized Ni-Al2 O3 bulk catalyst has a crystalline form with not only spherical shape,but also nanorod and nanometer silk,etc.Particles prepared by this method have good dispersion and uniform size,and narrow diameter distribution is observed between 10~50 nm.The Ni-Al2 O3 reduced by hydrogen also has a crystalline form,and nanostructure of reduced Ni-Al2 O3 is more orderly than before.Particles size after reduction is still in the nanoparticles scope.TPR results show that there are two reduction peak appeared in the structure of nanometer bulk Ni-Al2 O3 catalyst,and the low-temperature peak is NiO,high temperature reduction peak attributes to spinel structure which produced by the interaction of nickel and aluminum oxide.%以尿素为沉淀剂、六水硝酸镍为前躯体、表面活性剂(聚异丁烯马来酸三乙醇胺酯)和石油烃-150SN混合物作为模板剂，采用超增溶自组装法制得纳米 Ni-Al2 O3体相催化剂。对 Ni-Al2 O3体相催化剂进行了 TEM表征和氢气还原曲线(TPR)分析，并对沉淀反应的机理进行了探讨。结果表明，超增溶自组装纳米Ni-Al2 O3体相催化剂是晶体结构，形状除了球形，还有纳米棒、纳米丝等其他形状；通过超增溶自组装法制备出的微粒分散性良好，颗粒均匀、粒径分布(10~50 nm)较窄。Ni-Al2 O3经过 H2还原后仍是规整有序的晶体，而且还原后比还原前的晶体结构要规整有序，还原后的颗粒的粒径仍在纳米粒子范围内，属于纳米颗粒。TPR 分析结果表明，曲线出现了两个还原峰，低温峰归属于 NiO 结构，高温峰归属于镍与氧化铝相互作用产生的表面尖晶石结构。