铬酸铋系全光谱催化剂高活性和氧化能力增强机理

The research on full-spectrum photocatalysts is of great significance to greatly improve the utilization of sunlight. This project is intended to develop the bismuth chromate photocatalysts with full-spectrum response, high activity and strong mineralization ability. Through the controllable synthesis, a full-spectrum bismuth chromate photocatalyst with high activity, strong oxidation ability and visible-light activity up to 650 nm can be obtained. Moreover, by regulating the components, the valence band maximum position of bismuth chromate can be lowered, and the photocatalytic oxidation potential of the photogenerated holes also can be enhanced. Even under the red light irradiation, bismuth chromate can still produce strong oxidized species to mineralized phenol. Through the structural regulation of bismuth chromate, the polarization of the unit cell and built-in electric field of the bismuth chromate photocatalyst can be enhanced, resulting in its high photocatalytic activity. In addition, by controlling of the surface state electronic structure (surface defect structure), the valence band structure can be regulated, and the intrinsic activity of photocatalytic activity can also be extended to 700 nm. The mechanism of separation and transport of photogenerated charge of bismuth chromate photocatalyst will be demonstrated to reveal the photocatalytic active species and the mineralization mechanism for phenolic pollutants under red light irradiation. The implementation of this project can greatly improve the solar energy utilization efficiency of the photocatalyst and promote the development of a new full-spectrum photocatalyst.

全光谱光催化剂的研究对于大幅度提高光催化对太阳光的利用效率具有重要意义。本申请拟开展具有全光谱响应、高活性和强氧化能力的铬酸铋光催化剂的研究。通过可控合成可制备获得具有高活性、强氧化能力、可见光活性响应拓展到650纳米的铬酸铋全光谱光催化剂。通过组份调控可以实现铬酸铋价带顶位置的降低，增强光生空穴的光催化氧化电位，即使在红光激发下仍能产生对苯酚具有强矿化能力的强氧化性活性空穴物种。通过铬酸铋的结构调控，可以实现晶胞单元极化作用的增强，增强铬酸铋光催化剂的内建电场，从而产生光催化高活性。通过表面态电子结构调控（表面缺陷结构），实现对价带结构的调控，增强光催化本征活性和促进光活性拓展到700nm。阐明铬酸铋光催化剂的光生电荷的分离和传输规律，揭示在红光激发下的光催化活性物种以及对酚类污染物的降解反应和矿化反应机理。该课题的实施可以大幅度提高光催化剂的太阳能利用效率，促进新型全光谱光催化剂的发展

宽光谱光和高电荷分离效率的催化剂的研究对于大幅度提高光催化对太阳光的利用效率，应对能源与环境危机，具有重要意义。该项目从复合氧化物半导体的设计出发，以理论计算结果指导实验合成，成功构筑了宽光谱的单斜相Bi8CrO15纳米棒光催化剂，其光谱吸收范围可以拓展至678 nm, 理论太阳光谱效率达到了42.0%，实现了对有机污染的深度矿化和高效的水氧化性能，在420 nm光照下取得了2.87%的产氧量子效率，并通过表面缺陷、表面结构与异质结结构的调控，进一步提升了其光催化效率，提出晶体偶极能够诱导光催化材料产生内建电场，从而有效地促进光生电子空穴对的分离和提升光催化性能的学术思想，深度揭示了其能带结构和晶胞极化对电荷分离效率、光催化氧化能力和矿化能力的调控规律，深入理解铬酸铋系光催化剂的可见光活性物种以及催化反应机理。并进一步将该思想拓展到其他氧化物与有机光催化体系的材料设计与结构调控，深度揭示了分子与晶体极化所构筑的内建电场增强光催化性能的机理，为后续高性能光催化材料的设计与机理研究提供了更广阔的思路。