Preparation and catalytic evaluation of Au/γ -Al2O3nanoparticles for the conversion of 4-nitrophenol to 4-aminophenol by spectrophotometric method

Abstract

A set of catalysts having gold nanoparticles deposited on γ -Al 2 O3 ( Au/ γ -Al 2 O3) with lowest effectiveamount of gold content were prepared by successive impregnation and hydrogen reduction method. The structuralfeatures of prepared catalysts were analysed by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy(SEM), and Fourier transform infrared (FTIR). The catalytic activity was evaluated for the reduction of an organicpollutant 4-nitrophenol (4NP) to 4-aminophenol (4AP) by spectrophotometric analysis. Supported catalyst presentedexcellent catalytic ability to convert 4NP to 4AP in the presence of sodium borohydride (SBH) due to synergistic effectof Au NPs and mesoporous γ -Al 2 O3 support. The reduction reaction was also performed at a range of temperatures tocalculate kinetic parameters. The development of highly stable Au/γ -Al 2 O3 catalysts with lowest noble metal contentand recyclability made the process cost effective and may promote their applications in various fields including removalof organic pollutants in industrial waste water and high-temperature gas-phase reactions.