Facile sonochemical preparation of au-ZrO₂ nanocatalyst for the catalytic reduction of 4-nitrophenol

High-intensity ultrasonic waves have great potential for the green synthesis of various nanomaterials under mild conditions and offer an excellent alternative for hazardous chemical methods. Herein a facile approach for the eco-friendly synthesis of Au-ZrO₂ nanocatalyst with a high catalytic activity using a facile ultrasonic method is presented. Gold (Au) in the nanosize regime was successfully deposited on the surface of solvothermally synthesized monodispersed ZrO₂ nanoparticles (ZrO₂ NPs) in a very short period of time (5 min) at room temperature. Spherical shape small size Au nanoparticles that are uniformly dispersed on the surface of ZrO₂ nanoparticles were obtained. Notably, in the absence of ZrO₂ nanoparticles, HAuCl4 could not be reduced, indicating that nano-sized ZrO₂ not only acted as support but also helped to reduce the gold precursor at the surface. The as-prepared Au-ZrO₂ nanocatalyst was characterized by various techniques. The Au-ZrO₂ nanocatalyst served as a highly efficient reducing catalyst for the reduction of 4-nitrophenol. The reaction time decreased with increasing the amount of catalyst.