Hierarchically-structured SiO2-Ag@TiO2 hollow spheres with excellent photocatalytic activity and recyclability
Hierarchically-structured SiO2-Ag@TiO2 hollow spheres with excellent photocatalytic activity and recyclability
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具有优异光催化活性和可回收性的多级结构SiO2-Ag@TiO2空心球
DOI：
10.1016/j.jhazmat.2018.04.047
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发表时间：
2018
影响因子：
13.6
通讯作者：
Cao Shunsheng
中科院分区：
文献类型：
--
作者：
Zhang Ying;Chen Juanrong;Tang Hua;Xiao Yingguan;Qiu Shoufei;Li Songjun;Cao Shunsheng
提出了一种新型的SiO2-Ag@TiO2空心球（SAT）的制备方法，其中SiO2作为Ag纳米粒子的有效载体，而TiO 2保持其分级结构，并在光催化反应过程中阻止Ag纳米粒子的聚集. TiO 2作为光催化剂，由于其独特的结构，可以使污染物分子充分占据其内外表面，从而加速光生电子向基质的转移，从而提高光催化性能。与沉积在SiO2@TiO2（STA）表面的Ag纳米粒子相比，合成的SAT对四环素和传统染料的可见光和紫外光降解活性明显增强。其优异的光催化性能归因于光生电子的传输路径增强，e−/h+对复合概率降低，以及氧化和腐蚀的威胁降低。特别是，SAT在连续五次运行后仍然保持其光催化效率，即使样品在可见光照射下回收，远远超过STA在相同条件下的可重复使用性。因此，其优异的光催化活性和良好的可回收性使其在净化水中污染物和满足未来环境问题的需求方面更具潜力。
A new protocol for constructing sandwich-like SiO2-Ag@TiO2hollow spheres (SAT) is introduced, in which SiO2acts as an efficient support for the Ag nanoparticles (Ag NPs) immobilization, while TiO2maintains its hierarchical structure and prevents the aggregation of Ag NPs during the photocatalytic reaction. As a photocatalytic agent, the inner and outer surfaces of TiO2can be fully occupied by pollutants molecules because of its unique structure, which faster boosts the photo-generated electrons to transfer the substrates, leading to an enhanced photocatalytic performance. Compared with Ag NPs deposited on the surface of SiO2@TiO2(STA), the as-synthesized SAT exhibits a markedly enhanced visible-light and UV light activity than STA for degrading tetracycline and traditional dyes. The excellent photocatalytic performances are ascribed to the enhanced transport paths of photo-generated electrons, reduced recombination probability of e−/h+pairs, and decreased threat of oxidation and corrosion. Especially, the SAT still maintains its photocatalytic efficiency after five consecutive runs even though the sample is recovered under visible-light irradiation, far beyond the reusability of STA under the same conditions. Therefore, the outstanding photocatalytic activity and excellent recyclability make SAT more potential to purify aquatic contaminants and to meet the demands of future environmental issues.