Bai Jinwu, Li Yun, Wei Pengkun, Liu Jiandang, Chen Wei, Liu Lu
Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, P. R. China.
State Key Laboratory of Particle Detection and Electronics, University of Science & Technology of China (USTC), Hefei, Anhui, 230026, P. R. China.
Small. 2019 Jun;15(23):e1900020. doi: 10.1002/smll.201900020. Epub 2019 Apr 24.
Vacancy engineering is an effective strategy to enhance solar-driven photocatalytic performance of semiconductors. It is highly desirable to improve the photocatalytic performance of composite nanomaterials by the introduction of vacancies, but the role of vacancies and the heterostructure in the photocatalytic process is elusive to the composite nanomaterials. Herein, the introduction of I vacancies can significantly enhance the photocatalytic activity of Bi O -BiOI composite nanosheets in a synergistic manner. The excellent photocatalytic performance of the Bi O -BiOI composites is attributed to the combination of Bi O and BiOI and the existence of I vacancies in Bi O -BiOI composites. Specifically, density functional theory calculation shows that the existence of I vacancies would create a new electric states vacancy band below the conduction band of BiOI and thus can reduce the bandgap of BiOI nanosheets. This greatly facilitates the scavenging of the photogenerated electron on the surface of BiOI by Bi O , therefore, enhancing the overall photocatalytic activity of the composites. The enhanced photocatalytic efficiency is demonstrated by the degradation of tetracycline (TC), which reaches 96% after 180 min and by the high total organic carbon (TOC) removal (89% after 10 h visible light irradiation). This study provides a novel approach for the design of high-performance composite catalysts.
空位工程是提高半导体太阳能驱动光催化性能的有效策略。通过引入空位来改善复合纳米材料的光催化性能是非常可取的，但空位和异质结构在光催化过程中对复合纳米材料的作用尚不清楚。在此，引入碘空位可以以协同方式显著提高Bi₂O₃-BiOI复合纳米片的光催化活性。Bi₂O₃-BiOI复合材料优异的光催化性能归因于Bi₂O₃和BiOI的结合以及Bi₂O₃-BiOI复合材料中碘空位的存在。具体而言，密度泛函理论计算表明，碘空位的存在会在BiOI的导带下方产生一个新的电态空位带，从而可以降低BiOI纳米片的带隙。这极大地促进了Bi₂O₃对BiOI表面光生电子的捕获，因此提高了复合材料的整体光催化活性。通过四环素（TC）的降解证明了光催化效率的提高，180分钟后降解率达到96%，通过高的总有机碳（TOC）去除率（可见光照射10小时后为89%）也证明了这一点。该研究为高性能复合催化剂设计提供了一种新方法。
