Visible-light-driven photocatalytic formation of propylene carbonate using FeNbO₄/reduced graphene oxide composites

Photocatalytic cycloaddition of carbon dioxide to propylene oxide was achieved using a series of novel FeNbO₄/reduced graphene oxide composites. Three different mass ratios of reduced graphene oxide incorporated FeNbO₄ were used, namely, FeNbO₄–3% rGO, FeNbO₄–5% rGO, and FeNbO₄–10% rGO. Prepared photocatalysts were characterized using UV–Visible (UV–Vis) diffuse reflectance spectroscopy (DRS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) for determination of the specific surface area and porosity. The successful incorporation of reduced graphene oxide into FeNbO₄ was further supported with the enhanced photocatalytic performance of these composites, furthermore, FeNbO₄–5% rGO exhibited the highest photocatalytic cyclic carbonate formation reaching up to 57% yield. Detailed investigation shows that the prepared composites are promising heterogeneous photocatalysts for the cycloaddition of carbon dioxide under simulated visible light irradiation, their enhanced photocatalytic activities ascribed to the enhanced separation efficiency of photo-generated charge carriers. To the best of our knowledge, this study is the first to report the preparation of FeNbO₄/ reduced graphene oxide composites photocatalysts.