He Fei, Weon Seunghyun, Jeon Woojung, Chung Myoung Won, Choi Wonyong
Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea.
School of Health and Environmental Science, Korea University, Seoul, 02841, Korea.
Nat Commun. 2021 Oct 29;12(1):6259. doi: 10.1038/s41467-021-26541-z.
Photocatalytic air purification is widely regarded as a promising technology, but it calls for more efficient photocatalytic materials and systems. Here we report a strategy to introduce an in-situ water (self-wetting) layer on WO by coating hygroscopic periodic acid (PA) to dramatically enhance the photocatalytic removal of hydrophilic volatile organic compounds (VOCs) in air. In ambient air, water vapor is condensed on WO to make a unique tri-phasic (air/water/WO) system. The in-situ formed water layer selectively concentrates hydrophilic VOCs. PA plays the multiple roles as a water-layer inducer, a surface-complexing ligand enhancing visible light absorption, and a strong electron acceptor. Under visible light, the photogenerated electrons are rapidly scavenged by periodate to produce more •OH. PA/WO exhibits excellent photocatalytic activity for acetaldehyde degradation with an apparent quantum efficiency of 64.3% at 460 nm, which is the highest value ever reported. Other hydrophilic VOCs like formaldehyde that are readily dissolved into the in-situ water layer on WO are also rapidly degraded, whereas hydrophobic VOCs remain intact during photocatalysis due to the "water barrier effect". PA/WO successfully demonstrated an excellent capacity for degrading hydrophilic VOCs selectively in wide-range concentrations (0.5-700 ppmv).
光催化空气净化被广泛认为是一项很有前景的技术，但它需要更高效的光催化材料和系统。在此，我们报告一种通过涂覆吸湿的高碘酸（PA）在WO上引入原位水（自湿润）层的策略，以显著增强对空气中亲水性挥发性有机化合物（VOCs）的光催化去除。在环境空气中，水蒸气在WO上冷凝形成独特的三相（空气/水/WO）体系。原位形成的水层选择性地富集亲水性VOCs。PA起到多种作用，作为水层诱导剂、增强可见光吸收的表面络合配体以及强电子受体。在可见光下，光生电子被高碘酸盐迅速捕获以产生更多的•OH。PA/WO对乙醛降解表现出优异的光催化活性，在460nm处的表观量子效率为64.3%，这是迄今报道的最高值。其他容易溶解在WO上原位水层中的亲水性VOCs，如甲醛，也能迅速降解，而疏水性VOCs在光催化过程中由于“水屏障效应”保持完整。PA/WO成功展示了在宽浓度范围（0.5 - 700 ppmv）内选择性降解亲水性VOCs的优异能力。
