Organic Materials and Fiber Engineering Department, Chonbuk National University, Jeonju, 561-756, Republic of Korea,
Environ Sci Pollut Res Int. 2014 Jan;21(2):1425-35. doi: 10.1007/s11356-013-2027-9. Epub 2013 Aug 6.
Annihilation of electrons-holes recombination process is the main remedy to enhance the photocatalytic activity of the semiconductors photocatalysts. Doping of this class of photocatalysts by foreign nanoparticles is usually utilized to create high Schottky barrier that facilitates electron capture. In the literature, because nonpolar nanoparticles (usually pristine metals, e.g., Ag, Pt, Au, etc.) were utilized in the doping process, the corresponding improvement was relatively low. In this study, CdSO4-doped TiO2 nanoparticles are introduced as a powerful and reusable photocatalyst for the photocatalytic degradation of methomyl pesticide in concentrated aqueous solutions. The utilized CdSO4 nanoparticles form polar grains in the TiO2 matrix due to the electrons leaving characteristic of the sulfate anion. The introduced nanoparticles could successfully eliminate the harmful pesticide under the sunlight radiation within a very short time (less than 1 h), with a removal capacity reaching 1,000 mg pesticide per gram of the introduced photocatalyst. Moreover, increase in the initial concentration of the methomyl did not affect the photocatalytic performance; typically 300, 500, 1,000, and 2,000 mg/l solutions were completely treated within 30, 30, 40, and 60 min, respectively, using 100 mg catalyst. Interestingly, the photocatalytic efficiency was not affected upon multiple use of the photocatalyst. Moreover, negative activation energy was obtained which reveals super activity of the introduced photocatalyst. The distinct photocatalytic activity indicates the complete annihilation of the electrons-holes recombination process and abundant existence of electrons on the catalyst surfaces due to strong electrons capturing the operation of the utilized polar CdSO4 nanoparticles. The introduced photocatalyst has been prepared using the sol-gel technique. Overall, the simplicity of the synthesizing procedure and the obtained featured photocatalytic activity strongly recommend the introduced nanoparticles to treat the methomyl-containing polluted water.
电子-空穴复合过程的消除是增强半导体光催化剂光催化活性的主要方法。通常通过掺杂外来纳米粒子来掺杂这类光催化剂，以形成有利于电子捕获的高肖特基势垒。在文献中，由于掺杂过程中使用了非极性纳米粒子（通常是原始金属，例如 Ag、Pt、Au 等），因此相应的改善相对较低。在这项研究中，引入了 CdSO4 掺杂的 TiO2 纳米粒子作为一种强大且可重复使用的光催化剂，用于在浓水溶液中光催化降解灭多威农药。所使用的 CdSO4 纳米粒子由于硫酸盐阴离子的特征电子离开而在 TiO2 基体中形成极性颗粒。引入的纳米粒子能够在很短的时间内（不到 1 小时）成功地消除有害农药，引入的光催化剂每克可去除 1000 毫克农药。此外，增加灭多威的初始浓度不会影响光催化性能；通常在 30、30、40 和 60 分钟内，分别使用 100 毫克催化剂完全处理 300、500、1000 和 2000 毫克/升的溶液。有趣的是，光催化剂多次使用后其光催化效率不受影响。此外，还获得了负的活化能，这表明引入的光催化剂具有超活性。明显的光催化活性表明，由于利用的极性 CdSO4 纳米粒子的电子捕获操作，电子-空穴复合过程完全消除，并且催化剂表面存在丰富的电子。所引入的光催化剂是使用溶胶-凝胶技术制备的。总的来说，合成过程的简单性和获得的特征光催化活性强烈推荐引入的纳米粒子来处理含有灭多威的污染水。
