BiVO4/Bi复合纳米结构的构筑及其可见光催化还原CO2的研究

Photocatalytic reduction of CO2 has important significance in energy development and environment management. However, the present photocatalysts exhibit the low quantum efficiency and narrow absorption range, thus restricting its application. In this project, BiVO4 nanostructures will be coupled with bismuth nanoparticles to form heterojunction structures (BiVO4/Bi) with high photocatalytic activity. The main work in this project is as follows: . (1) Using BiVO4 nanostrucrues with especial morphologies as templates, BiVO4/Bi composites will be prepared by chemical reduction reaction, in which Bi3+ ions are reduced to form Bi nanoparticles at the surface of BiVO4 nanostrucrues. The BiVO4/Bi composites with different composition, microstructure and heterointerface will be prepared by controlling the reaction conditions.. (2) The effects of composition, microstructure and heterointerface of the.BiVO4/Bi composites on the photocatalytic activity and selectivity of the CO2.photoreduction reactions will be investigated systematically. On basis of this study, the BiVO4/Bi photocatalysts with the optimized microstructure and composition will be fabricated.. (3) The relationship between photocatalytic activity and transfer properties of photoinduced charge carriers will be studied by means of material characterization and theoretical calculation. The effect of the heterostructures on the photocatalytic properties will be discussed.. (4) The reaction mechanism and nature of photocatalytic reduction of CO2 on the surface of BiVO4/Bi composites will be explored.. The results will provide theoretical basis and lay the foundation for real application of BiVO4/Bi composites in photocatalytic reduction of CO2.

光催化还原CO2在能源开发和环境治理方面具有重要的意义，但是目前光催化剂的量子效率还比较低，光响应范围还比较窄,制约了光催化技术的应用。本项目拟将BiVO4纳米结构与Bi纳米颗粒复合以构建高效的光催化还原CO2体系。具体地：(1) 以BiVO4纳米结构为模板，采用原位化学还原反应将BiVO4纳米颗粒表面的部分铋离子还原成铋单质，通过优化工艺制备出具有特定化学组成、微观结构和异质界面的BiVO4/Bi复合材料；(2) 系统研究BiVO4/Bi复合材料的化学组成、微观结构、异质界面对光催化还原CO2的催化活性及产物选择性的影响；(3) 利用材料表征和理论计算相结合的方法揭示BiVO4/Bi复合材料光生电荷特性与光催化活性之间的联系；(4) 探索BiVO4/Bi复合纳米结构表面光催化还原CO2的机理和本质。本研究将为BiVO4/Bi复合材料在光催化还原CO2的实际应用提供理论依据和奠定实验基础。

本项目以研究钒酸铋/铋基异质结构光催化还原CO2的性能及作用机理为主要内容，重点开展钒酸铋/铋基异质结构的调控合成、光催化还原CO2的性能以及构效关系研究，探究影响其光催化性能的本质因素，取得了如下主要进展：(1) 探索出一种仅通过改变铋源和钒源比例就可以控合成不同形貌钒酸铋的新方法；(2) 基于溶剂热和水热过程，探索出用于制备结合紧密、金属铋颗粒分布均匀的钒酸铋/铋异质结构的化学合成新方法，通过优化工艺调控了钒酸铋/铋的化学组成、微观结构和异质界面；(3) 以BiVO4/Bi为模板，开发出BiVO4/Bi-Cu、BiVO4/Bi-Ag、BiVO4/Bi/Cu2O等新型异质结构光催化剂；(4) 揭示了所制备的异质结构光催化剂的化学组成、微观结构、异质界面对光生电荷特性、光催化还原CO2的催化活性、产物选择性的影响规律；(5) 阐明了各异质结构光催化剂表面光催化还原CO2的机理和本质。该项目为调控异质结光催化剂中电荷的传输、降低电荷的复合几率、提高电荷的利用率、构建新型高效的异质结光催化剂提供了新策略。