Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technologies, Jiangsu Key Laboratory of Atmospheric Environmental Monitoring & Pollution Control, School of Environmental Science & Engineering, Nanjing University of Information Science & Technology, No. 219 Ningliu Road, Nanjing, 210044, China.
Department of Geography and Environmental Science, University of Reading, Whiteknights, Reading, RG6 6AB, UK.
Environ Sci Pollut Res Int. 2023 Jan;30(4):10191-10201. doi: 10.1007/s11356-022-22835-x. Epub 2022 Sep 7.
Formaldehyde (HCHO) has been one of the important air pollutants, and the effective removal of HCHO at ambient temperature has been a big challenge. In this work, the synergistic effect of photo-thermal oxidation with Bi-TiO/MnFeO for a low concentration of HCHO was investigated. MnFeO was synthesized by the complexation method (CM) and co-precipitation (CP), and TiO with Bi doping supported on MnFeO was prepared by using the hydrothermal method to obtain a higher oxidation performance. The results demonstrated an excellent oxidation activity of MnFeO (CM) for HCHO at ambient temperature, attributed to the morphology effect (large surface areas and small crystal sizes), the large absorption of oxygen, and the interaction and oxygen vacancy formed between MnO and FeO. Although Bi-TiO/MnFeO showed a similar result as MnFeO at 48 h, the oxidation activities for HCHO were improved prominently under photo-thermal oxidation at 12 h. The improvement was ascribed to the synergistic effect of Bi-TiO and MnFeO with surface adsorbed oxygen, and more generated reactive oxygen species on the surface. In particular, 2 wt% Bi-TiO/MnFeO displayed the highest activity (90.2%) and good stability (5 cycles), and the HCHO average conversion was increased from 46.2 to 58.2% at 12 h. The feasible oxidation mechanism and reaction pathway were also interpreted. This work provides a new insight for the development of photocatalysts supported on transition metal oxides to oxidize HCHO at ambient temperature.
甲醛（HCHO）是重要的空气污染物之一，在环境温度下有效去除 HCHO 是一个巨大的挑战。在这项工作中，研究了 Bi-TiO/MnFeO 光热氧化协同作用对低浓度 HCHO 的去除效果。采用共沉淀法（CP）和络合法（CM）合成 MnFeO，并采用水热法在 MnFeO 上负载 Bi 掺杂的 TiO，以获得更高的氧化性能。结果表明，MnFeO（CM）在环境温度下对 HCHO 具有优异的氧化活性，这归因于其形貌效应（较大的比表面积和较小的晶粒尺寸）、对氧气的强吸收能力，以及 MnO 和 FeO 之间的相互作用和氧空位的形成。尽管 Bi-TiO/MnFeO 在 48 h 时与 MnFeO 具有相似的结果，但在 12 h 的光热氧化下，其对 HCHO 的氧化活性明显提高。这种改善归因于 Bi-TiO 和 MnFeO 与表面吸附氧的协同作用，以及表面上更多生成的活性氧物种。特别是，2wt%Bi-TiO/MnFeO 表现出最高的活性（90.2%）和良好的稳定性（5 个循环），HCHO 的平均转化率从 12 h 的 46.2%提高到 58.2%。还解释了可行的氧化机制和反应途径。这项工作为开发在环境温度下氧化 HCHO 的过渡金属氧化物负载型光催化剂提供了新的思路。
