The product selectivity and efficiency of photocatalytic CO₂ reduction are often restricted by the multi-electron transfer and reactive centers in the artificial photosynthetic system. To overcome these limitations, in this work, atomically thin carbon nitride (CN) coupled Bi₉O_7.5S₆ (BOS) nanoplates were fabricated as a two-dimensional/two-dimensional (2D/2D) Van der Waals (VDW) heterojunction for CO₂ photoreduction. Our experimental and density functional theory (DFT) calculations showed that the CO* could be adsorbed more strongly on BOS than CN, which could be further hydrogenated before desorption, explaining the observation why the main products of photocatalytic CO₂ reduction on BOS was CH₄ and CH₃OH. Benefiting from the 2D/2D VDW heterojunction, 20CN/BOS revealed a CO generation rate of 37.2 μmol g_catalyst⁻¹ under visible light irradiation, roughly 14.9-fold and 1.4-fold higher than that of BOS and CN alone. Our work paves a way to design new VDW hetero-structured photocatalysts for CO₂ reduction to valuable products.

人工光合作用系统中的多电子转移和反应中心经常限制光催化CO ₂还原的产物选择性和效率。为了克服这些限制，在这项工作中，原子薄的氮化碳（CN）耦合的Bi ₉ O _7.5 S ₆（BOS）纳米板被制成二维/二维（2D / 2D）范德华（VDW）异质结用于CO _2光还原。我们的实验和密度泛函理论（DFT）计算表明，CO *在BOS上的吸附能力强于CN，后者在脱附前可以进一步氢化，从而解释了为什么光催化CO ₂的主要产物BOS的还原是CH ₄和CH ₃ OH。得益于2D / 2D VDW异质结，20CN / BOS在可见光照射下的CO生成速率为37.2μmolg_催化剂^-1，比单独的BOS和CN高约14.9倍和1.4倍。我们的工作为设计新的VDW异质结构光催化剂铺平了道路，该催化剂可将CO ₂还原为有价值的产品。