Ag-decorated GaN for high-efficiency photoreduction of carbon dioxide into tunable syngas under visible light

Abstract

Visible light-driven photoreduction of CO2 and H2O to tunable syngas is an appealing strategy for both artificial carbon neutral and Fischer-Tropsch processes. However, the development of photocatalysts with high activity and selectivity remains challenging. For this case, we here design a hybrid catalyst, synthesized by in situ deposition of Ag crystals on GaN nanobelts, that delivers a tunable H-2/CO ratio between 0.5 and 3 under visible light irradiation (lambda > 400 nm). The obtained photocatalyst delivers a maximal turnover frequency value of 3.85 h(-1) and a corresponding yield rate of 2.12 mmol h(-1) g(-1) for CO production, while the photocatalytic activity keeps stable during five cycling tests. Additionally, syngas can be detected even at lambda > 600 nm. Experiments and mechanistic studies reveal that the existence of Ag crystals not only extends the light absorption region but also promotes the charge transfer efficiency, and thereby leading to a photocatalytic improvement. Accordingly, the present work affords an opportunity for developing an efficient photo-driven system by using solar energy to alleviate CO2 emissions.