Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technologies, Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, No. 219 Ningliu Road, Nanjing, 210044, China.
Environ Sci Pollut Res Int. 2019 Apr;26(10):9672-9685. doi: 10.1007/s11356-019-04277-0. Epub 2019 Feb 7.
Photocatalytic oxidation of formaldehyde (HCHO) is considered as one of the promising ways to resolve indoor air HCHO pollution. TiO has been well known as the most extended application in photocatalysis due to its strong oxidizing ability and stability. Owing to high activity under visible light irradiation, TiO and BiO doping mixed with BiWO was analyzed in this study. The formation of two kinds of heterojunction caused efficient charge separation, leading to the effective reduction in the recombination of photo-generated electron and hole. The special structure and enhanced performance of these catalysts were analyzed. For the first time, the loading of alkali salts was researched for photocatalytic oxidation. In order to understand the reaction mechanism of alkali salts enhanced effects, the catalysts were investigated by using BET, XRD, UV-Vis, FT-IR, SEM, and XPS. The results found more than 2 wt% of NaSO loading and the mixed methods with different solutions were key factors affecting the performance of catalysts. Nearly 92% HCHO conversion could be completed over BiWO/BiTiO (NaSO), and the concentration of HCHO was only 0.07 mg/m for 24 h, which was below the limit of specification in China. The results also indicated that the solution mixing method was more favorable to increase the HCHO conversion due to decrease the size of BiTO particles. The catalysts with NaSO loading provided more surface-adsorbed oxygen that facilitated the desorption of CO and markedly increased the photocatalytic oxidation of HCHO. Graphical abstract Plausible mechanism over W-Bi2WO6/ Bi0.15Ti0.85O2-Na2SO4 (1:4) catalysts.
光催化氧化甲醛（HCHO）被认为是解决室内空气 HCHO 污染的一种很有前途的方法。TiO 由于其强氧化能力和稳定性而被广泛应用于光催化。由于在可见光照射下具有高活性，本研究分析了 TiO 和 BiO 掺杂混合 BiWO。两种异质结的形成导致有效电荷分离，从而有效减少光生电子和空穴的复合。对这些催化剂的特殊结构和增强性能进行了分析。首次研究了负载碱盐对光催化氧化的影响。为了了解碱盐增强效果的反应机制，使用 BET、XRD、UV-Vis、FT-IR、SEM 和 XPS 对催化剂进行了研究。结果发现，负载超过 2wt%的 NaSO 和不同溶液的混合方法是影响催化剂性能的关键因素。在 BiWO/BiTiO（NaSO）上，超过 92%的 HCHO 可以转化，并且在 24 小时内，HCHO 的浓度仅为 0.07mg/m，低于中国的规范限制。结果还表明，由于 BiTO 颗粒尺寸减小，溶液混合方法更有利于提高 HCHO 的转化率。负载 NaSO 的催化剂提供了更多的表面吸附氧，有利于 CO 的解吸，并显著提高了 HCHO 的光催化氧化。
