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

Solar-driven reduction of CO 2 to valuable carbon products is an attractive pathway for energy production. The CO 2 photoreduction efficiency is determined by the CO 2 mass transfer and charge carrier recombination efficiency. Herein, we propose a Bi 2 WO 6 –C 3 N 4 heterojunction with the hydrophobic–hydrophilic diphase to promote mass transfer and charge separation. The amphipathic heterojunction achieved high-efficiency photocatalytic conversion of CO 2 into CO and CH 4 in H 2 O vapor, yielding up to 25.54 and 7.69 μmol h –1 g –1 of CO and CH 4, respectively. The well-designed heterojunction increased the CO 2 concentration on the hydrophobic surface and enhanced the H 2 O 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 CO 2 reduction.