合成对氨基苯酚Pt/C催化剂失活的研究

硝基苯催化加氢合成对氨基苯酚反应中，加氢Pt/C催化剂的稳定性决定生产成本。实验结果表明，催化剂循环使用10次，将失活催化剂过滤，在60%的硝酸溶液中加热回流3 h，用去离子水充分洗涤后，催化剂可恢复部分活性。第一次硝酸活化处理后，催化剂还可以使用4次左右。采用原子吸收、BET、SEM及XRD等测试方法对新鲜催化剂和经过重复实验的催化剂进行表征，结果表明，催化剂失活的主要原因为有机物覆盖在催化剂表面造成表面积下降和孔堵塞，致使催化剂丧失活性中心。在催化剂使用过程中，活性组分Pt流失及Pt 金属晶粒长大也会导致催化剂失活。

Study on deactivation of Pt/C p-aminophenol synthesis catalysts

The cost of nitrobenzene hydrogenation to p-aminophenol was much dependent on stability of the Pt/C catalyst. The experimental results showed that the catalyst eould be repeatedly used for at least ten times under optimum reaction condition. Activity of the catalyst was partly recovered and could be used for four times after the first treatment by 60% HNO3 for 3 h. N2 adsorption, atomic absorption, X-ray diffraction （XRD） and SEM results indicated that the causes behind deactivation of the catalyst were that organic species eovered the surface and resulted in loss of surface area and blocking-up of the pores, and hence loss of active sites. Loss of Pt and growth of Pt particles during hydrogenation process were also the causes behind the deactivation.