2D/2D g-C₃N₄@BiOI S-scheme heterojunction with gas-liquid-solid triphase interface for highly efficient CO₂ photoreduction

Over the past decades, there has been considerable research attention dedicated to the conversion of CO₂ into valuable chemical fuels such as CH₄, CO, and CH₃OH through CO₂ photoreduction. Despite these efforts, the efficiency of current CO₂ photoreduction systems remains unsatisfactory, primarily due to the rapid recombination of photoinduced charges and inadequate co-adsorption of CO₂ and H₂O molecules. Herein, we present a novel and highly efficient CO₂ photoreduction system based on an intimate 2D/2D g-C₃N₄@BiOI step-scheme (S-scheme) heterojunction constructed on hydrophobic carbon fiber paper. The resulting heterojunction demonstrates outstanding photocatalytic ability for CO₂ reduction, achieving high CO selectivity (77.8%) and activity (458.0 µmol h⁻¹ m⁻² for CO). The remarkable photocatalytic performance can be attributed to the well-designed S-scheme heterojunction, which enhances charge separation efficiency, and the establishment of a gasliquid-solid triphase interface, ensuring the simultaneous and sufficient supply of CO₂ and H₂O. This work introduces new perspectives for the design of highly efficient photocatalytic CO₂ reduction systems.