In this study, hollow-structured Bi decorated g-C₃N₄ hybrids were successfully fabricated by a simple solvothermal method and applied for the first time to the photocatalytic reduction of CO₂. Remarkably, the composites exhibited excellent CO₂ conversion efficiencies in the presence of H₂O under visible light irradiation compared to unmodified g-C₃N₄, especially for the production of CH₄. The optimum photocatalyst 30-Bi/g-C₃N₄ presented the best production of CO and CH₄, approximately 3 times and 9 times as high as those of unmodified g-C₃N₄, respectively. A series of characterizations were conducted to explore the essence behind such an enhancement; we found that enhanced light harvesting, quick separation of photoinduced carriers and more negative conduction band, due to the formation of a Schottky junction between g-C₃N₄ and Bi metal and the solvothermal process, co-contributed for the enhanced CO₂ conversion; A more important finding was that the surprising improvement of CH₄ yield stem primarily from the introduction of the hollow-structured Bi, which enabled the accumulation of electrons on its surface exhibiting the metal-like property. The CO₂ photocatalytic conversion process was also investigated by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) spectroscopy and we found that HCO₃⁻ and CO₂⁻ were active intermediates over 30-Bi/g-C₃N₄ and Bi doping could promote the activation of CO₂. In summary, this work presented hollow-structured Bi decorated g-C₃N₄ composites as new materials for energy applications, proving once more the meta-like nature of bismuth, and laying the groundwork for the utilization of Bi in CO₂ photocatalytic reduction processes.

在这项研究中，成功地通过简单的溶剂热方法制备了中空结构的Bi装饰的gC ₃ N ₄杂化物，并将其首次应用于光催化还原CO ₂。值得注意的是，与未改性的gC ₃ N ₄相比，该复合材料在可见光照射下在H ₂ O存在下表现出出色的CO ₂转化效率，特别是对于CH ₄的生产。最佳的光催化剂30-Bi / gC ₃ N ₄表现出最佳的CO和CH ₄产量，分别是未改性gC _3的3倍和9倍N ₄。进行了一系列表征，以探索这种增强背后的本质。我们发现，由于在gC ₃ N ₄和Bi金属之间形成了肖特基结以及溶剂热过程，光捕获载体的快速分离和更多的负导带得以共同促进了CO _2的转化。一个更重要的发现是，CH ₄收率的惊人提高主要源于中空结构化Bi的引入，该结构使电子能够在其表面上呈现出类似金属的特性积累。一氧化碳₂光催化转换处理也被研究了原位漫反射红外线傅里叶变换光谱法（DRIFT）光谱和我们发现，HCO ₃ ^-和CO ₂ ^-为活性中间体30-Bi系/ GC ₃ Ñ ₄和Bi掺杂能够促进活化的CO ₂。总而言之，这项工作提出了中空结构的Bi装饰的gC ₃ N ₄复合材料作为能源应用的新材料，再次证明了铋的类间本质，并为Bi在CO ₂光催化还原过程中的利用奠定了基础。