BiVO4/复合金属氧化物异质结的构筑及光催化脱硫性能研究

Photocatalytic desulfurization has been become one of the most promising deep desulfurization technologys, because of many advantages such as operation without using H2,mild reaction condition , easy technology. The core of this technology is to synthetize the photocatalyst which can be driven by visible light. Monoclinic BiVO4 has been of great interest for photochemical processes because of its narrow band gap and visible-light responsive. However, the applications of pure BiVO4 were limited due to its poor adsorptive performance and low photocatalytic efficiency caused by the difficult migration of photogenerated electron–hole pairs. Therefore, the development of new type BiVO4-based composites has high fundamental scientific value, and will have great practical value which is applied to the field of photocatalytic desulfurization. Based on our intial preliminary findings, the aim of this project is design and assembly of a new type of BiVO4-based heterojunction which has high catalytic activity under visible-light illumination. According to the characteristics of mixed metal oxide (MMO) with a narrow band gap, high luminous efficiency, stable chemical structure and diverse components, the vavious type of BiVO4-MMO heterojunction will been prepared. The effect of metal oxide type, preparation method, synthesis conditions and other factors on band structure of BiVO4-based material has been systematic studied. Moreover, the relationship between the band structure and photocatalytic desulfurization performance of the material will also be investigated for the development of catalysis to lay the theoretical and experimental foundation.

光催化脱硫技术具有非临氢操作、反应条件温和、工艺简单等优点，成为近年最有发展潜力的深度脱硫方法，而该技术的核心是开发具有可见光响应的光催化剂。单斜结构的BiVO4作为一类新型的具有可见光响应的光催化剂受到了研究者的广泛关注。但是，纯BiVO4光生载流子易于复合，使得其光催化脱硫活性较弱。所以，开发新型BiVO4基复合材料具有重要的科学意义，将其应用于光催化脱硫领域具有巨大的应用价值。在已取得的初步研究结果基础上，本项目拟设计具有可见光响应的高催化活性BiVO4/复合金属氧化物异质结化合物。利用复合金属氧化物的禁带宽度窄、发光效率高、结构稳定、组分多样等特点，构筑不同种类的BiVO4/复合金属氧化物异质结复合材料，系统研究金属氧化物种类和制备方法及合成条件等对BiVO4基材料能带结构的调控规律，揭示材料能带结构对光催化脱硫性能的影响规律，为催化科学的发展奠定理论和实验基础。

光催化脱硫技术具有非临氢操作、反应条件温和、工艺简单等优点，成为近年最有发展潜力的深度脱硫方法，而该技术的核心是开发具有可见光响应的光催化剂。单斜结构的BiVO4作为一类新型的具有可见光响应的光催化剂受到了研究者的广泛关注。但是，纯BiVO4光生载流子易于复合，使得其光催化脱硫活性较弱。混合金属氧化物的复合负载，不仅扩大了可见光的吸收范围，同时增强了可见光的吸收强度，而且降低了光致荧光光谱强度，并使得平带电势负移。以上三方面的特性改善为高效光催化活性提供了基础。考察可见光照射下的光催化活性发现，负载提高了0.5 mol•L-1 Na2SO4溶液中的阳极光电流密度；重要的是，以噻吩溶于正辛烷为模拟油，经负载改性的光催化材料极大地提高了光催化氧化脱硫性能，当负载比例为0.3:5时，CoAl-MMO/BiVO4复合光催化剂对模拟油的脱硫率高达98.58%。利用复合金属氧化物的禁带宽度窄、发光效率高、结构稳定、组分多样等特点，构筑了不同种类的BiVO4/复合金属氧化物异质结复合材料，系统研究了金属氧化物种类和制备方法及合成条件等对BiVO4基材料能带结构的调控规律，揭示了材料能带结构对光催化脱硫性能的影响规律，为催化科学的发展奠定理论和实验基础。