Enabling Interfacial Lattice Matching by Selective Epitaxial Growth of CuS Crystals on Bi₂WO₆ Nanosheets for Efficient CO₂ Photoreduction into Solar Fuels

Abstract

Photocatalytic CO2 reduction serves as an important technology for value‐added solar fuel production; however, it is generally limited by interfacial charge transport. To address this limitation, a two‐dimensional/two‐dimensional (2D/2D) p‐n heterojunction CuS‐Bi2WO6 (CS‐BWO) with highly connected and matched interfacial lattices was designed via a two‐step hydrothermal tandem synthesis strategy. The integration of CuS with BWO created a robust interface electric field and provided fast charge transfer channels due to the work function difference, as well as highly connected and matched interfacial lattices. The p‐n heterojunction promoted electron transfer from the Cu to Bi sites, leading to coordination of Bi sites with high electronic density and low oxidation state. The Bi sites in BWO nanosheets facilitated the adsorption and activation of CO2, and generation of high‐coverage key intermediate b‐CO32‐, while broad light‐harvesting CuS (CS) provide abundant photoinduced electrons that were injected into the conduction band of BWO for CO2 photoreduction reaction. Remarkably, the p‐n heterojunction CS‐BWO exhibited CO and CH4 yields of 135.7 and 62.5 µmol g‐1, respectively, which were significantly higher than those of CS, BWO, and physical mixture CS‐BWO nanosheets. This work provided an innovative design strategy for developing high‐activity heterojunction photocatalyst for converting CO2 into value‐added solar fuels.