Huang Bing-Shun, Su En-Chin, Huang Yun-Ya, Tseng Hui-Hsin
Taiwan Research Institute, Taipei 251, Taiwan, R.O.C.
Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan, R.O.C.
J Nanosci Nanotechnol. 2018 Mar 1;18(3):2235-2240. doi: 10.1166/jnn.2018.14237.
Pt/TiO2 photocatalysts with controllable phase were successfully prepared by controlling the hydrolysis pH values during the sol-gel process followed by Pt photodeposition. The effect of different phases of TiO2 coated with Pt on the catalytic properties and the photocatalytic activities were also investigated. The characterization results of the synthesis of TiO2 under neutral/alkaline and acidic conditions during the hydrolysis step revealed the facile formation of the anatase phase and the brookite/rutile phase, respectively. Pt/TiO2 photocatalysts prepared at hydrolysis pH values of 2, 7, and 10 had different TiO2 phase compositions, but the main crystalline sizes of the photocatalysts were all close to 6 nm. The Pt/TiO2 particles prepared at various hydrolysis pH values were all spheroidal. The PL results indicated that the anatase/rutile junction of a Pt/TiO2 sample had a lower recombination rate than did the anatase phase of Pt/TiO2 owing to the longer recombination pathway. However, the anatase phase of Pt/TiO2 exhibited better degradation ability than the anatase/rutile junction of Pt/TiO2, and the degradation rate decreased with a decrease in the anatase composition of TiO2, indicating that anatase composition in the Pt/TiO2 system played an important role of enhancing the photocatalytic degradation of Acid Red 1 dye.
通过在溶胶 - 凝胶过程中控制水解pH值并随后进行Pt光沉积，成功制备了具有可控相的Pt/TiO₂光催化剂。还研究了涂覆有Pt的TiO₂不同相态对催化性能和光催化活性的影响。水解步骤中在中性/碱性和酸性条件下合成TiO₂的表征结果表明，分别容易形成锐钛矿相和板钛矿/金红石相。在水解pH值为2、7和10时制备的Pt/TiO₂光催化剂具有不同的TiO₂相组成，但光催化剂的主要晶体尺寸均接近6nm。在各种水解pH值下制备的Pt/TiO₂颗粒均为球形。PL结果表明，由于复合路径更长，Pt/TiO₂样品的锐钛矿/金红石结的复合率低于Pt/TiO₂的锐钛矿相。然而，Pt/TiO₂的锐钛矿相表现出比Pt/TiO₂的锐钛矿/金红石结更好的降解能力，并且降解率随着TiO₂锐钛矿组成的降低而降低，这表明Pt/TiO₂体系中的锐钛矿组成在增强酸性红1染料的光催化降解中起重要作用。
