Catalytic Properties of Platinum Nanoclusters Supported on Iron Oxides for the Solvent-Free Hydrogenation of Halonitrobenzene

It is of significance to investigate the support effect in heterogeneous metal catalysts. Pt/Fe3O4, Pt/y-Fe2O3, and Pt/alpha-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/y-Fe2O3 or Pt/alpha-Fe2O3 was higher than that over Pt/Fe3O4, while the catalytic activity over PtiFe(3)O(4) was 50% higher than that over Pt/alpha-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.