Liu Shou-Heng, Lin Wei-Xing
Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
J Hazard Mater. 2019 Apr 15;368:468-476. doi: 10.1016/j.jhazmat.2019.01.082. Epub 2019 Jan 24.
The indoor air quality should be highly addressed because people spend more time staying in indoor environments. Photocatalytic degradation of indoor pollutants (e.g., formaldehyde) is one of the most promising and environmental friendly technologies. In this work, a heterostructured photocatalyst combining graphitic carbon nitride (g-CN), TiO and waste zeolites (g-CN-TiO/waste zeolites) is developed by a facile calcination and sol-gel method. The prepared photocatalysts exhibit the superior visible-light-responsive activities toward formaldehyde degradation (k = 0.0127 min) which is higher than g-CN-TiO (k = 0.0123 min) and P25 (k = 0.0056 min). Over 90% of low-concentration formaldehyde can be oxidized by g-CN-TiO/waste zeolites under a commercial LED light within 300 min. The electron spin resonance spectra indicate that the superoxide radical anions (O-) photogenerated on the g-CN-TiO/waste zeolites under visible light irradiation are responsible for the decomposition of formaldehyde. The enhancement in the photocatalytic decomposition of formaldehyde in the air is possibly due to the heterojunction between g-CN (the enhanced absorption of visible light) and TiO (fast transfer of photogenerated electrons from g-CN) as well as assisted adsorption of gas-phase formaldehyde via waste zeolites. This work also exemplifies the valorization of industrial silicate wastes to efficient photocatalytic coatings for indoor air purification.
由于人们在室内环境中停留的时间更长，室内空气质量应得到高度重视。光催化降解室内污染物（如甲醛）是最有前景且环保的技术之一。在这项工作中，通过简便的煅烧和溶胶 - 凝胶法制备了一种由石墨相氮化碳（g-CN）、TiO和废沸石组成的异质结构光催化剂（g-CN-TiO/废沸石）。所制备的光催化剂对甲醛降解表现出优异的可见光响应活性（k = 0.0127 min⁻¹），高于g-CN-TiO（k = 0.0123 min⁻¹）和P25（k = 0.0056 min⁻¹）。在商用LED灯下，300分钟内g-CN-TiO/废沸石可氧化90%以上的低浓度甲醛。电子自旋共振光谱表明，可见光照射下g-CN-TiO/废沸石上光生的超氧自由基阴离子（O₂⁻）是甲醛分解的原因。空气中甲醛光催化分解的增强可能归因于g-CN（增强可见光吸收）与TiO（光生电子从g-CN快速转移）之间的异质结以及废沸石对气相甲醛的辅助吸附。这项工作还例证了将工业硅酸盐废料转化为用于室内空气净化的高效光催化涂层。
