Department of Energy Engineering/KENTECH Institute for Environmental and Climate Technology, Korea Institute of Energy Technology (KENTECH), Naju 58330, Korea.
Civil, Environmental, and Architectural Engineering, Korea University, Seoul 02841, Korea.
Environ Sci Technol. 2022 Aug 2;56(15):10829-10837. doi: 10.1021/acs.est.2c02975. Epub 2022 Jun 29.
Given the widespread use of TiO, its release into aquatic systems and complexation with dissolved organic matter (DOM) are highly possible, making it important to understand how such interactions affect photocatalytic activity under visible light. Here, we show that humic acid/TiO complexes (HA/TiO) exhibit photoactivity (without significant electron-hole activation) under visible light through ligand-to-metal charge transfer (LMCT). The observed visible-light activities for pollutant removal and bacterial inactivation are primarily linked to the generation of HO the conduction band. By systematically considering molecular-scale interactions between TiO and organic functional groups in HA, we find a key role of phenolic groups in visible-light absorption and HO photogeneration. The photochemical formation of HO in river waters spiked with TiO is notably elevated above naturally occurring HO generated from background organic constituents due to LMCT contribution. Our findings suggest that HO generation by HA/TiO is related to the quantity and functional group chemistry of DOM, which provides chemical insights into photocatalytic activity and potential ecotoxicity of TiO in environmental and engineered systems.
鉴于 TiO 的广泛应用，其向水生系统的释放以及与溶解有机物 (DOM) 的络合高度可能，因此了解这种相互作用如何在可见光下影响光催化活性非常重要。在这里，我们表明，通过配体到金属电荷转移 (LMCT)，腐殖酸/TiO 复合物 (HA/TiO) 在可见光下表现出光活性（没有明显的电子空穴激活）。观察到的污染物去除和细菌失活的可见光活性主要与导带中 HO 的生成有关。通过系统地考虑 TiO 和 HA 中有机官能团之间的分子尺度相互作用，我们发现酚基团在可见光吸收和 HO 光生成中起着关键作用。由于 LMCT 的贡献，用 TiO 掺杂的河水的 HO 的光化学形成明显高于背景有机成分产生的天然 HO。我们的研究结果表明，HA/TiO 产生的 HO 与 DOM 的数量和官能团化学有关，这为 TiO 在环境和工程系统中的光催化活性和潜在生态毒性提供了化学见解。
