负载途径对炭气凝胶载Pt催化剂性能的影响

Effects of method of loading on properties of carbon aerogels supported Pt catalyst

选择孔隙率高、孔隙尺寸小、比表面积大、电导率高、孔径大小及分布可控的新型炭材料炭气凝胶(CAs)为载体,通过在成品CAs表面负载和在CAs制备过程中同步负载两种途径制备了CAs负载的Pt催化剂,利用XRD、TEM、ICP及电化学循环伏安测试等手段对比讨论了负载途径对CAs载Pt催化剂物化性能及甲醇氧化催化活性的影响。结果表明,同步负载虽然可以简化制备工艺,但所制得的催化剂样品中催化活性组分Pt颗粒大、团聚严重、分散性差、负载量低,而且有许多Pt颗粒被包裹在CAs内部,因而导致了催化剂的有效利用率和催化性能降低。相反,通过在成品CAs表面负载的方法可以制得Pt颗粒小、分散均匀、实际负载量接近理论设计的高性能催化剂。

Carbon aerogels （CAs） supported Pt catalysts were prepared separately by directly loading of Pt on the surface of CAs and simultaneously loading of Pt during the synthesis of CAs respectively. XRD, TEM, ICP and electrochemical cyclic voltammograms were used to evaluate and comparatively discuss the effects of method of loading on the properties of CAs supported Pt catalyst. The results showed that simultaneous loading led to large Pt particle size, poor Pt dispersion and low Pt loading quantity, resulting in poor catalytic performance for methanol oxidation. On the contrary, high performance CAs supported catalyst with well dispersed small Pt particle size could be obtained via direct loading.