Plasma-promoted Au/TiO2 nanocatalysts for photocatalytic formaldehyde oxidation under visible-light irradiation
Plasma-promoted Au/TiO2 nanocatalysts for photocatalytic formaldehyde oxidation under visible-light irradiation
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可见光照射下等离子体促进的 Au/TiO2 纳米催化剂光催化甲醛氧化
DOI：
10.1016/j.cattod.2019.03.033
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发表时间：
2019
期刊：
影响因子：
5.3
通讯作者：
Zhu Ai-Min
中科院分区：
文献类型：
--
作者：
Li Xiao-Song;Ma Xiao-Yuan;Liu Jing-Lin;Sun Zhi-Guang;Zhu Bin;Zhu Ai-Min
Au/TiO 2纳米催化剂是一种很有前途的可见光等离子体光催化剂，但传统的煅烧活化方法存在Au纳米颗粒团聚和活化周期较长的问题。我们在这里报告，短期的O2等离子体处理使Au/TiO 2催化剂表现出更高的可见光催化活性甲醛（HCHO）氧化相比，煅烧活化的样品。X射线光电子能谱（XPS）表征结果表明，O2等离子体活化后的Au/TiO 2催化剂表面金属Au含量达到72.4%，表面氧物种含量达到29.8%，这不仅使催化剂表面的阳离子Au在甲醛氧化反应中迅速还原，而且促进了甲醛在催化剂表面的初步氧化反应.紫外-可见漫反射光谱、光致发光光谱和漫反射红外傅里叶变换光谱研究表明，O2等离子体活化的Au/TiO 2催化剂在可见光照射下，通过热电子转移机制促进了HCHO氧化过程中O2-和OH自由基的生成，显著地促进甲酸盐氧化成碳酸盐、碳酸盐分解并因此促进HCHO氧化。
As a promising plasmonic photocatalyst under visible-light irradiation, Au/TiO2nanocatalyst commonly suffers from risk of Au nanoparticles aggregation and relatively long activation period by using the conventional calcination activation method. We report here that a short-term O2plasma treatment enables the Au/TiO2catalyst to exhibit higher visible-light photocatalytic activity for formaldehyde (HCHO) oxidation compared with the calcination activated sample. X-ray photoelectron spectroscopy characterization suggests that Au/TiO2catalyst activated by O2plasma achieves metallic Au content of 72.4% and surface oxygen species content of 29.8%, which not only lead to rapid reduction of cationic Au in HCHO oxidation but also facilitate the preliminary oxidation of HCHO to dioxymethylene and formate on catalyst surface. UV–vis diffuse reflectance spectra, photoluminescence spectra and diffuse reflectance infrared Fourier transform spectra measurements indicate that O2plasma activated Au/TiO2catalyst presents an enhanced visible-light absorption and surface charge transfer efficiency in HCHO oxidation, which accelerates the formation of superoxide (O2−) and OHradical dotradicals via hot electron transfer mechanism under visible-light irradiation, remarkably promoting formate oxidation to carbonate, carbonate decomposition and thus HCHO oxidation.