A novel bimetallic (Au-Pd)-decorated reduced graphene oxide nanocomposite enhanced Rhodamine B photocatalytic degradation under solar irradiation

Abstract

Nowadays, water quality is one of the main challenges facing humanity. Recently, hybrid nanomaterials have attracted great attention because they can treat water solutions. In this study, Sol-Immobilization synthesized monometallic (Pd and Au) and bimetallic (Pd-Au) hybrid nanomaterials supported on reduced graphene oxide (rGO) were synthesized as catalysts for the photocatalytic Rhodamine B degradation under direct sunlight. The as-synthesized nanomaterials were characterized using XRD, Raman spectroscopy, UV-DRS spectrophotometer, HR-TEM techniques, and X-ray Photoelectron Spectroscopy. The catalytic activities of Pd/rGO and Au/rGO were compared with those of Aux-Pdy/rGO, and a higher photocatalytic degradation efficiency was found for the bimetallic-supported rGO sample. At optimum conditions, Au0.75-Pd0.25/rGO achieved the best dye degradation efficiency of 98%. The reusability study results showed that Au0.75-Pd0.25/rGO retained 89% of its initial activity after five successive uses. The scavenging study results proved that hydroxyl radicals are the major reactive species in the photocatalytic degradation reaction. These findings indicate that Au0.75-Pd0.25/rGO catalyst is a promising material for the treatment of water contaminated with organic dyes under sunlight.