Gold Nanoparticles Supported on Alumina as a Catalyst for Surface Plasmon-Enhanced Selective Reductions of Nitrobenzene

Au nanoparticles supported on alumina (Au/Al2O3) with average particle size of 3.9 +/- 0.7 nm and surface plasmon band centerned at 516.5 nm were prepared by deposition-precipitation method, and their photocatalytic activities for the reduction of nitrobenzene using either formic acid in acetonitrile (method A) or KOH in 2-propanol (method B) were investigated. Even at room temperature, the Au/Al2O3 was found to be highly active and selective for conversion of nitrobenzene to aniline when used with formic acid in acetonitrile or to azobenzene when performed with KOH in 2-propanol under irradiation with green light-emitting diode (517 nm).