Rapid sun-light driven photocatalytic functions of 3D rGO/ZnO/Ag heterostructures via improved charge transfer kinetics

Enhancing photon absorption across visible region could be of great significance in visualizing rapid photocatalytic reactions. In this regard, we report on a novel three-dimensional (3D) rGO/ZnO/Ag heterostructure processed via solvothermal and photoreduction techniques. The structural studies revealed the formation of a complete rGO/ZnO/Ag heterostructure. The microscopic images revealed ZnO on rGO specimens and Ag on both ZnO and rGO surface. Enhanced visible region photon absorption and lowering in band gap values was realized in rGO/ZnO/Ag specimens over rGO/ZnO. The photocatalytic performance evaluated through dye degradation reactions under sunlight illumination indicated 3D heterostructure to exhibit rapid and enhanced photocatalytic activity. A schematic mechanism was established to illustrate the enhanced charge transfer kinetics involved in the reactions. Additionally, studies on increased photocatalytic reaction rate for addition of H2O2 and role of reaction temperature was also made. The obtained heterostructure also demonstrated ≈99% efficiency towards recycled photocatalytic reactions.