Chen Xi, Sheng Xia, Zhou Hang, Liu Zhiping, Xu Minmin, Feng Xinjian
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
Small. 2024 Jun;20(24):e2310128. doi: 10.1002/smll.202310128. Epub 2024 Jan 4.
Hydroxyl radical (OH) with strong oxidation capability is one of the most important reactive oxygen species. The generation of OH from superoxide radicals (O ) is an important process in visible-light-driven photocatalysis, but the conversion generally suffers from slow reaction kinetics. Here, a hydrophobicity promoted efficient OH generation in a visible-light-driven semiconductor-mediated photodegradation reaction is reported. Hydrophobic TiO that is synthesized by modifying the TiO surface with a thin polydimethylsiloxane (PDMS) layer and rhodamine B (RhB) are used as model semiconductors and dye molecules, respectively. The surface hydrophobicity resulted in the formation of a solid-liquid-air triphase interface microenvironment, which increased the local concentration of O. In the meanwhile, the saturated adsorption quantity of RhB on hydrophobic TiO is improved by five-fold than that on untreated TiO. These advantages increased the density of the conduction band photoelectrons and O generation, and stimulated the conversion of O to OH. This consequently not only increased the kinetics of the photocatalytic reaction by an order of magnitude, but also altered the oxidation route from conventional decolorization to mineralization. This study highlights the importance of surface wettability modulation in boosting OH generation in visible-light-driven photocatalysis.
具有强氧化能力的羟基自由基（OH）是最重要的活性氧物种之一。超氧自由基（O）生成OH是可见光驱动光催化中的一个重要过程，但该转化通常存在反应动力学缓慢的问题。在此，报道了在可见光驱动的半导体介导光降解反应中，疏水性促进了高效的OH生成。通过用薄聚二甲基硅氧烷（PDMS）层修饰TiO表面合成的疏水TiO和罗丹明B（RhB）分别用作模型半导体和染料分子。表面疏水性导致形成固 - 液 - 气三相界面微环境，这增加了O的局部浓度。同时，RhB在疏水TiO上的饱和吸附量比未处理的TiO提高了五倍。这些优势增加了导带光电子的密度和O的生成，并促进了O向OH的转化。这不仅使光催化反应动力学提高了一个数量级，还将氧化途径从传统的脱色转变为矿化。这项研究突出了表面润湿性调控在促进可见光驱动光催化中OH生成方面的重要性。
