【摘要】 采用10%H2S/H2对Ni2P/SiO2催化剂进行预处理,利用X射线衍射、电感耦合等离子发射光谱、X射线光电子能谱、CO化学吸附、H2程序升温脱附、NH3程序升温脱附及活性评价等方法研究了H2S预处理对催化剂结构和氯苯加氢脱氯反应性能的影响.结果表明,即使在873K进行H2S预处理,Ni2P/SiO2催化剂体相结构及Ni2P晶粒大小没有发生变化,但导致Ni2P晶粒表面形成了磷硫镍相(NiPxSy),同时使表面溢流氢数量增加.硫物种的存在不仅阻塞了部分镍中心,使催化剂表面镍中心密度降低,也导致镍中心的缺电子性进一步增加.经H2S预处理后Ni2P/SiO2催化剂上氯苯加氢脱氯反应的转化频率(TOF)明显提高,这可能与催化剂表面Ni物种的缺电子性增强及溢流氢数量增多有关.更多还原

【Abstract】 The effect of 10% H2S/H2 treatment on the structure of Ni2P/SiO2 and its activity for the hydrodechlorination of chlorobenzene was investigated using X‐ray diffraction, inductively coupled plasma atomic emission spectroscopy, X‐ray photoelectron spectroscopy, CO chemisorption, H2 temperature‐programmed desorption, NH 3 temperature‐programmed desorption, and activity tests. The H2S/H2 treatment did not change the Ni2P phase or crystallite size even at temperatures as high as 873 K. However, S species were incorporated in the surface of the Ni2P crystallites to form surface phosphosulfide (NiPxSy ) species, which blocked the Ni sites and induced their further electron‐deficiency. H2S/H2 treatment also led to an increase of spilt‐over hydrogen species. The treated Ni2P/SiO2 catalyst had higher turnover frequencies in the hydrodechlorination of chlorobenzene than the untreated catalyst. This was ascribed to the increased electron‐deficiency of Ni site and a greater amount of spilt‐over hydrogen species.更多还原