ABSTRACT

AgBr/BiVO₄ photocatalysts with heterojunction structures were prepared using a hydrothermal method. To analyse phase composition and microstructure, samples were characterised by X-ray diffraction and scanning electron microscopy, respectively. Photoluminescence measurements were used to characterise the recombination rate of photogenerated electron–hole pairs. The phase structure, chemical state and optical properties of heterojunctions were analysed by UV-visible diffuse-reflectance spectrometry. AgBr/BiVO₄ showed high efficiency for the degradation of rhodamine B under visible light irradiation. Hydrothermal temperature and pH values exhibited significant influence on band gap energy and the recombination rate of electron–hole pairs of AgBr/BiVO₄, reflective of photocatalytic properties. Results show that at 160°C and pH of 7 AgBr/BiVO₄ achieved the best photocatalytic activity, for which the visible light-absorption range of the AgBr/BiVO₄ heterojunction was significantly enhanced. Photodegradation catalysis of RhB was most efficiently achieved at a level of approximately 56.72% for a reaction time of 140 min.

摘要

采用水热法制备具有异质结结构的AgBr/BiVO ₄光催化剂。为了分析相组成和微观结构，分别通过 X 射线衍射和扫描电子显微镜对样品进行了表征。光致发光测量用于表征光生电子 - 空穴对的复合率。采用紫外-可见漫反射光谱法分析异质结的相结构、化学状态和光学性质。AgBr/BiVO ₄在可见光照射下表现出高效降解罗丹明 B。水热温度和pH值对AgBr/BiVO _{4 的}带隙能量和电子-空穴对的复合率有显着影响，反映光催化性能。结果表明，在160℃、pH值为7的AgBr/BiVO ₄下，AgBr/BiVO ₄的光催化活性最好，AgBr/BiVO ₄异质结的可见光吸收范围显着增强。在 140 分钟的反应时间内，RhB 的光降解催化效率最高，约为 56.72%。