Highly Active Photoreduction of Atmospheric-Concentration CO2 into CH3COOH over Palladium Particles on Nb2O5 Nanosheets

Abstract

The endeavor to drive CO₂ photoreduction towards the synthesis of C₂ products is largely thwarted by the colossal energy hurdle inherent in C−C coupling. Herein, we load active metal particles on metal oxide nanosheets to build the dual metal pair sites for steering C−C coupling to form C₂ products. Taking Pd particles anchored on the Nb₂O₅ nanosheets as an example, the high-angle annular dark-field image and X-ray photoelectron spectroscopy demonstrate the presence of Pd−Nb metal pair sites on the Pd-Nb₂O₅ nanosheets. Density functional theory calculations reveal these sites exhibit a low reaction energy barrier of only 1.02 eV for C−C coupling, implying that the introduction of Pd particles effectively tailors the reaction step to form C₂ products. Therefore, the Pd-Nb₂O₅ nanosheets achieve a CH₃COOH evolution rate of 13.5 μmol g⁻¹ h⁻¹ in photoreduction of atmospheric-concentration CO₂, outshining all other single photocatalysts reported to date under analogous conditions.