Engineering a Hydrophobic–Hydrophilic Diphase in a Bi2WO6–C3N4 Heterojunction for Solar-Powered CO2 Reduction

Solar-driven reduction of CO2 to valuable carbon products is an attractive pathway for energy production. The CO2 photoreduction efficiency is determined by the CO2 mass transfer and charge carrier recombination efficiency. Herein, we propose a Bi2WO6–C3N4 heterojunction with the hydrophobic–hydrophilic diphase to promote mass transfer and charge separation. The amphipathic heterojunction achieved high-efficiency photocatalytic conversion of CO2 into CO and CH4 in H2O vapor, yielding up to 25.54 and 7.69 μmol h–1 g–1 of CO and CH4, respectively. The well-designed heterojunction increased the CO2 concentration on the hydrophobic surface and enhanced the H2O adsorption on the hydrophilic surface. Consequently, the reactant gases could be directly fed into the system to consume the photogenerated charges. In situ diffuse reflectance infrared Fourier transform spectroscopy and molecular dynamics simulations elucidated the enhanced activity and reaction mechanism during photocatalysis. The hydrophobic–hydrophilic diphase heterojunction serves as a template for the development of reliable solar-powered systems for CO2 reduction.