Sunlight-Induced photochemical synthesis of Au nanodots on α-Fe₂O₃@Reduced graphene oxide nanocomposite and their enhanced heterogeneous catalytic properties

In this present study, we report the synthesis of Au nanodots on α-Fe₂O₃reduced graphene oxide (RGO) based hetero-photocatalytic nanohybrids through a chlorophyll mediated photochemical synthesis. In this process, chlorophyll induces a rapid reduction (30 min) of Au³⁺ ions to Au° metallic nanodots on α-Fe₂O₃RGO surface under sunlight irradiation. The nucleation growth process, photo-induced electron-transfer mechanism and physico-chemical properties of the Auα-Fe₂O₃RGO ternary nanocomposites were systematically studied with various analytical techniques. This novel photochemical synthesis process is a cost-effective, convenient, surfactant-less, and scalable method. Moreover, the prepared ternary nanocomposites enhanced catalytic activity as compared to pure α-Fe₂O₃ and α-Fe₂O₃RGO. The advantages and synergistic effect of Auα-Fe₂O₃RGO exhibit, (i) a broader range of visible-light absorption due to visible light band gap of α-Fe₂O₃, (ii) lower recombination possibility of photo-generated electrons and holes due to effect of Au and (iii) faster electron transfer due to higher conductivity of RGO. Therefore, the prepared Auα-Fe₂O₃RGO hetero-photocatalytic nanohybrids exhibited a remarkable photocatalytic activity, thus enabling potential active hetero-photocatalyst for industrial and environmental applications.