Schottky-Functionalized Type-II heterojunction of Ag/CuNb2O6/g-C3N4: Efficient photoredox capability of CO2 to valuable fuel products via gas phase adsorption

Owing to encyclopedic energy crises and ecological concerns, the conversion of solar energy into sustainable value-added fuel products using a reasonable photocatalyst has received a lot of interest. The crucial challenge of the photoreduction of CO2 into fuel products such as CO and CH4 is the minor output and poor selectivity. Herein, a novel synthesized schottky-functionalized type-II heterojunction, Ag/CuNb2O6/g-C3N4 (Ag/CNO/g-CN), is extensively characterized to provide insights regarding its photocatalytic performance in reducing CO2. More significantly, electron paramagnetic resonance was employed to assist in understanding the inclusion of Schottky-junction and type II heterojunction charge transfer. The CO2 photoreduction to CO (2.78 μmol g−1h−1) with Ag/CNO/g-CN was 5- and 3-fold higher than single CNO and single g-CN, and the CO2 photoreduction to CH4 was 0.15 μmol g−1h−1 under simulated solar irradiation. This enhanced CO2 photoreduction was attributed to the large surface area and type II heterojunction, which promoted the separation as well as the transformation of photoinduced e−/h+ pairs and the superior redox ability of charge carriers. The composite's excellent photocatalytic efficiency towards CO2 was exceptionally enhanced by depositing Ag on CNO/g-CN. This study paves the way for immediate needs to explore the selective conversion of CO2 into CO and CH4 via systematic designing and effective schottky-functionalized type-II heterojunction.