Wang Ji-Chao, Yao Hong-Chang, Fan Ze-Yu, Zhang Lin, Wang Jian-She, Zang Shuang-Quan, Li Zhong-Jun
College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450052, China.
ACS Appl Mater Interfaces. 2016 Feb 17;8(6):3765-75. doi: 10.1021/acsami.5b09901. Epub 2016 Feb 3.
Rational design and construction of Z-scheme photocatalysts has received much attention in the field of CO2 reduction because of its great potential to solve the current energy and environmental crises. In this study, a series of Z-scheme BiOI/g-C3N4 photocatalysts are synthesized and their photocatalytic performance for CO2 reduction to produce CO, H2 and/or CH4 is evaluated under visible light irradiation (λ > 400 nm). The results show that the as-synthesized composites exhibit more highly efficient photocatalytic activity than pure g-C3N4 and BiOI and that the product yields change remarkably depending on the reaction conditions such as irradiation light wavelength. Emphasis is placed on identifying how the charge transfers across the heterojunctions and an indirect Z-scheme charge transfer mechanism is verified by detecting the intermediate I3(-) ions. The reaction mechanism is further proposed based on the detection of the intermediate (•)OH and H2O2. This work may be useful for rationally designing of new types of Z-scheme photocatalyst and provide some illuminating insights into the Z-scheme transfer mechanism.
由于Z型光催化剂在解决当前能源和环境危机方面具有巨大潜力，其合理设计与构建在二氧化碳还原领域备受关注。在本研究中，合成了一系列Z型BiOI/g-C3N4光催化剂，并在可见光照射（λ > 400 nm）下评估了它们将二氧化碳还原为一氧化碳、氢气和/或甲烷的光催化性能。结果表明，所合成的复合材料表现出比纯g-C3N4和BiOI更高的光催化活性，并且产物产率根据诸如照射光波长等反应条件而显著变化。重点在于确定电荷如何在异质结间转移，通过检测中间产物I3(-)离子验证了间接Z型电荷转移机制。基于对中间产物(•)OH和H2O2的检测进一步提出了反应机理。这项工作可能有助于合理设计新型Z型光催化剂，并为Z型转移机制提供一些有启发性的见解。
