BiOX(Cl,Br,I)/Bi2WO6异质结型复合光催化剂用于高浓度氮氧化物的脱除

海中船舶排放的废气是大气污染的来源之一，其中的氮氧化物能使海洋酸化，不仅危害海洋生态系统，还会造成沿海城市空气污染，对人的身体健康也造成危害。光催化脱除大气中的氮氧化物被认为是可靠且有潜力的高级氧化脱除技术，但目前的研究大多针对低浓度（10^-9级）下氮氧化物脱除，针对船舶尾气中较高浓度（10^-6级）氮氧化物脱除的研究较少。本文采用超声辅助法制备了BiOX(Cl, Br, I)/Bi₂WO₆复合催化剂，紫外可见吸收光谱得到BiOX(Cl, Br, I)/Bi₂WO₆的带隙能分别为3.1eV、2.6eV和1.8eV，并且计算了其导带电位。光电流实验表明，BiOCl/Bi₂WO₆复合材料的光电流强度高于BiOBr/Bi₂WO₆和BiOI/Bi₂WO₆。模拟光催化脱硝实验表明，BiOCl/Bi₂WO₆在紫外线下NO的脱除率为37.5%，且BiOX/Bi₂WO₆复合光催化剂在5次循环后表现出良好的稳定性。通过原位红外吸收光谱分析，对BiOX/Bi₂WO₆催化剂上进行NO光催化氧化的中间产物进行了鉴定，提出了NO的氧化脱除途径。

BiOX(Cl,Br, I)/Bi2WO6 heterojunction composites as photocatalysts for high concentration NO removal

The exhaust gas emitted by marine vessels is one of the air pollution sources, and the nitrogen oxides in the gas could cause ocean acidification, marine ecosystem damage, air pollution over coastal cities, and people’s health problems. Photocatalytic removal of nitrogen oxides from atmosphere is considered to be a reliable and potential advanced oxidation removal technology, but the current studies are mostly focused on the elimination of nitrogen oxides of low concentration(10^-9 level), and those on high concentration(10^-6 level)nitrogen oxides removal from ship exhausts are still rare. The heterojuncted BiOX(Cl, Br, I)/Bi₂WO₆ were prepared through a one-step ultrasonic-assisted method, and applied in the NO removal from exhaust gas. The band-gap energies of BiOX(Cl, Br, I)/Bi₂WO₆ were estimated to be 3.1eV, 2.6eV and 1.8eV, respectively. The conduction band potentials of pristine Bi₂WO₆ and BiOX/Bi₂WO₆ were calculated. The photocurrent density of BiOCl/Bi₂WO₆ composite electrode was higher than that of BiOBr/Bi₂WO₆ and BiOI/Bi₂WO₆, and BiOCl/Bi₂WO₆ showed the highest activity with the maximum NO removal rate of 37.5% under UV light. BiOX/Bi₂WO₆ revealed good stability after five cycles. In situ DRIFTS tests of NO photocatalytic oxidation on BiOX/Bi₂WO₆ were employed to identify the reaction intermediates and the NO oxidation pathway was proposed based on the electrochemical and photocurrent density measurements as well as in situ reaction study.