【摘要】 复相金属催化剂中的载体效应研究具有重要意义。我们以结构不同的氧化铁载体吸附"非保护型"Pt金属纳米簇制备了具有相同Pt纳米簇的Pt/Fe₃O₄、Pt/γ-Fe₂O₃和Pt/α-Fe₂O₃催化剂,考察了其在无溶剂条件下（本体条件）催化邻氯硝基苯（o-CNB）选择性氢化反应的性能,发现三种铂/氧化铁催化剂的催化选择性远高于商购铂/碳催化剂,Pt/γ-Fe₂O₃和Pt/α-Fe₂O₃的催化选择性明显高于Pt/Fe₃O₄,而Pt/Fe₃O₄的催化活性较Pt/α-Fe₂O₃高50%。铂/氧化铁对不同卤代硝基苯的本体选择性氢化反应表现出优良的催化性能,相应卤代苯胺产物的选择性均可达到99%以上。考察了温度、氢气压力对Pt/Fe₃O₄催化o-CNB本体氢化性能的影响。本工作为理解氧化铁负载金属纳米簇催化剂的特殊催化性质,进而发展高效金属纳米簇基催化体系提供了新的基础。更多还原

【Abstract】 It is of significance to investigate the support effect in heterogeneous metal catalysts. Pt/Fe₃O₄, Pt/γ-Fe₂O₃, and Pt/α-Fe₂O₃ nanocomposites with the same Pt nanoclusters were prepared by adsorbing Pt colloidal particles stabilized with simple ions and solvent molecules on different iron oxide supports. The catalytic performances over the as-prepared catalysts for the selective hydrogenation of o-chloronitrobenzene（o-CNB）in the absence of solvent were evaluated. It was found that the catalytic activity and selectivity over the prepared iron oxide-supported Pt nanocluster catalysts were higher than those of a commercial Pt/C catalyst. The selectivity towards o-chloroaniline over Pt/γ-Fe₂O₃ or Pt/α-Fe₂O₃ was higher than that over Pt/Fe₃O₄, while the catalytic activity over Pt/Fe₃O₄ was 50% higher than that over Pt/α-Fe₂O₃. The Pt/iron oxide catalysts also exhibited excellent catalytic properties for the solvent-free selective hydrogenation of other tested halonitrobenzenes, with the selectivity to corresponding haloanilines being > 99%. In addition, the influences of temperature and hydrogen pressure on the solvent-free selective hydrogenation of o-CNB over Pt/Fe₃O₄ were studied. This work is helpful in understanding the superior properties of iron oxide-supported metal nanocluster catalysts and provides a foundation for further developing highly efficient catalytic systems based on metal nanoclusters.更多还原