Reduced Graphene Oxide-Cadmium Sulfide Nanorods Decorated with Silver Nanoparticles for Efficient Photocatalytic Reduction Carbon Dioxide Under Visible Light

Photocatalytic CO2 reduction is an attractive approach for the direct conversion of solar energy into chemical fuels. In this study, we synthesized a composite material that consists of Ag, reduced graphene oxide (RGO), and CdS nanorods as a photocatalyst for CO2 reduction. The morphological, structural, optical, and electrochemical properties of the resultant nanocomposite (Ag-RGO-CdS) were investigated by using various physical techniques (e.g., XRD, SEM, TEM, X-ray photoelectron spectroscopy, UV/Vis diffuse reflectance spectroscopy, and electrochemical impedance spectroscopy). Our results indicate that the Ag-RGO-CdS nanocomposites exhibit an enhanced photocatalytic activity for the conversion of CO2 into CO, and the optimum activity is achieved over 1.0wt% Ag-3.0 wt% RGO-CdS. This enhanced performance can be ascribed to the multifunctional promoting effects of RGO and Ag in the composite. On one hand, RGO and Ag can act as electron acceptors, which enhances the separation efficiency of photogenerated carriers. On the other hand, the incorporation of RGO and Ag can improve the adsorption and activation of CO2, which results in the enhancement of the photocatalytic reduction of CO2 to CO. Furthermore, a possible mechanism for photocatalytic CO2 reduction over the Ag-RGO-CdS nanocomposites was proposed. This study demonstrates a semiconductor-based hybrid for efficient photocatalytic CO2 reduction by virtue of the combinational effect of dual cocatalysts.