【摘要】 以膨胀石墨担载壳聚糖,采用金属诱导化学镀法制备了负载型Ni-B非晶态合金催化剂.通过X射线衍射、电感耦合等离子体发射光谱、扫描电子显微镜、透射电子显微镜和选区电子衍射等技术研究了壳聚糖对Ni-B催化剂非晶性质、组成、形貌、粒径及分散度的影响.以环丁烯砜加氢制环丁砜和对氯硝基苯加氢制对氯苯胺为探针反应,考察了壳聚糖对负载型Ni-B非晶态合金催化剂催化性质的影响,讨论了壳聚糖用量及水溶性壳聚糖的相对分子质量对催化剂性质的影响.结果表明,壳聚糖介质的引入能够提高活性组分的分散度,减小活性组分的粒径,从而明显提高了催化剂的催化加氢活性.当壳聚糖在载体表面形成单层分散时催化剂活性最高.分子质量相对较低的水溶性壳聚糖有利于生成粒径小、分散性好和催化活性高的Ni-B非晶态合金催化剂.更多还原

【Abstract】 A series of chitosan-mediated expanded graphite-supported amorphous Ni-B alloy catalysts were successfully prepared by a silver-catalyzed electroless plating method in an aqueous solution.The effects of chitosan on the structure,composition,surface texture,and dispersion of Ni-B particles on expanded graphite were characterized by X-ray powder diffraction,inductively coupled plasma analysis,transmission electron microscopy,selected area electron diffraction,and scanning electron microscopy.The characterization results show that the amorphous structure of Ni-B particles is not influenced by chitosan.The activity of as-prepared catalysts was tested by the hydrogenation of sulfolene to sulfolane and the selective hydrogenation of p-chloronitrobenzene to pchloroaniline.In comparison with the catalyst without chitosan,the presence of a proper amount of chitosan in the catalyst leads to homogeneous dispersion of Ni-B particles,small size of Ni-B particles,and high catalytic activity.更多还原