Distinguished performance of biogenically synthesized reduced-graphene-oxide-based mesoporous Au–Cu2O/RGO ternary nanocomposites for sonocatalytic reduction of nitrophenols in water

Abstract

In order to achieve a sustainable environment, the development of eco-friendly protocols for the production of noble metal catalysts has been the primary focus of major research. Ternary nanocomposites (TNCs) comprising Au–Cu₂O anchored on reduced graphene oxide (Au–Cu₂O/RGO) were synthesised employing a novel one-pot greener approach using sugarcane bagasse (SB) waste and Fehling's solution without engaging harmful chemicals as reagents and surfactants. In addition to the mild reducing capability of the polysaccharides present in SB, it also induces functionalization of RGO, avoiding aggregation of the reduced sheets and thereby providing in situ stabilization of Cu₂O. The sonocatalytic performance of biogenically synthesized Au–Cu₂O/RGO TNCs for reducing nitrophenols to the corresponding aminophenol in the presence of sodium borohydride (NaBH₄) as a reducing agent was estimated. TNCs showed high performance in the sonocatalytic reduction of 4-nitrophenols (4-NP), 2-nitrophenol (2-NP), and 3-nitrophenol (3-NP) with 88%, 72%, and 78% conversion within 90, 60, and 40 seconds, respectively. The sonocatalytic activity of Au–Cu₂O/RGO was enhanced compared to that of Cu₂O and Cu₂O/RGO due to the easier electron transfer process. The current work showcases a novel, eco-friendly, and benign protocol for the synthesis of nanocomposites (NCs) and simultaneously emphasises the exploration of decorated metal oxide as a nanocatalyst with high catalytic potential; compared to unanchored metal oxide nanoparticles (NPs), the supported NCs exhibit greater efficacy and ease of recovery.