Photoreduction CO₂ to hydrocarbons are the sustainable and green methods to solve energy shortages and environmental pollution problems. Therefore, the development of efficient and environment-friendly photocatalysts remains a huge challenge, while coupling co-catalyst on traditional photocatalysts is a potential approach for improving photocatalytic activity. Here, a novel BiO_2-x co-catalyst coupled g-C₃N₄ photocatalyst was prepared by a simple hydrothermal approach for the photocatalytic reduction of CO₂. The experimental results proved that BiO_2-x/g-C₃N₄ composites played a vital part for promoting the photocatalytic capability. The 20 % BiO_2-x/g-C₃N₄ composites exhibited the best photocatalytic capability under the simulated visible-light. A maximum yield of CO (42.29 μmol/gcat) and CH₄ (7.2 μmol/gcat) were obtained, which were 3.8 and 2.5 times that over pure g-C₃N₄, and its apparent quantum yield (AQY) was 1.5 % at 420 nm. According to the characterization results, the significantly increased photocatalytic activity could be ascribed to larger specific surface area, stronger visible-light absorption properties and more effective separation and transfer of photogenerated electron-hole pairs. Our finding provides a certain reference for the development and application of novel co-catalyst.

将CO ₂光还原为碳氢化合物是解决能源短缺和环境污染问题的可持续和绿色方法。因此，开发有效且环保的光催化剂仍然是巨大的挑战，而将助催化剂偶联到传统的光催化剂上是提高光催化活性的潜在途径。在这里，通过一种简单的水热方法制备了一种新型的BiO _2-x助催化剂偶联的gC ₃ N ₄光催化剂，用于CO ₂的光催化还原。实验结果证明BiO _2-x / gC ₃ N ₄复合材料对于提高光催化能力起着至关重要的作用。20％BiO _2-x / gC ₃ N ₄复合材料在模拟可见光下表现出最佳的光催化能力。获得的CO（42.29μmol/ gcat）和CH ₄（7.2μmol/ gcat）的最大产率分别是纯gC ₃ N _4的3.8和2.5倍，其表观量子产率（AQY）在420 nm下为1.5％。根据表征结果，光催化活性的显着提高归因于更大的比表面积，更强的可见光吸收性能以及更有效的光生电子-空穴对的分离和转移。我们的发现为新型助催化剂的开发和应用提供了一定的参考。