Influence of plasmonic metals (Ag, Cu) on overall CO2 photoreduction activity of β-Ga2O3

Abstract

Plasmonic metals can substantially promote the photo-activity of the conventional photocatalyst. Herein, we inserted Ag and Cu nanoparticles in β-Ga2O3 to photo reduce CO2 by water. The relative content of Ag and Cu governs the photo-activity. 2Ag: Cu/ β-Ga2O3 exhibits the optimum activity, which was 1.81, 1.57, 1.5 times higher than using pristine β-Ga2O3 for CO, H2, and CH4, respectively. Ag and Cu favored the production of CO and CH4, respectively. Bimetals improved the optical and electronic properties and increased the photocurrent responses by 8-folds. In situ DRIFTS for isotopic-labelled 13CO2 and ESR spectroscopy provided insight into the charge transfer mechanism and key intermediates. The molecular dynamics simulation indicates that bimetals induced hydrophobicity in β-Ga2O3 helped to populate CO2 molecules near the surface which slowly diffuse along the axial direction. Combining these findings, a plausible mechanism is given which could help in engineering catalysts for other solar energy applications.