Stability and kinetics of plasmonic photocatalysts for gas-phase toluene degradation were assessed by monitoring total volatile organic compound (TVOC) concentration versus UV-A illumination time in a recirculating batch reactor (plate-type flow-through). Plasmonic samples were produced by either coating silver on, or layering silica-protected or unprotected silver beneath, the photocatalyst. Samples were modeled using Finite difference time domain simulations, and characterized. Experimental results show that silver-coated photocatalysts, and photocatalysts layered over unprotected silver, exhibit initially high TVOC degradation rates compared to TiO₂, but suffer from relatively rapid deactivation attributed to silver oxidation. Photocatalysts layered over silica-protected (i.e., silica-coated) silver exhibited improved stability versus photocatalysts layered over unprotected (i.e., uncoated) silver, and demonstrated more than 50% increase in reaction rate constant and more than a threefold increase in apparent quantum yield over the non-plasmonic control sample (TiO₂ over SiO₂). The results of this study demonstrate that a silica layer can help slow down fouling of silica nanoparticles, and that silica-coated silver nanoparticles not only help speed up reaction rate overall but also appear to speed up release of adventitious carbon from the photocatalyst surface during the initial phase of a reaction.

Graphic Abstract

中文翻译：

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二氧化硅保护的等离子光催化剂在气相降解总挥发性有机化合物中的稳定性和动力学

通过在循环间歇式反应器（板式流通）中监测总挥发性有机化合物（TVOC）浓度与UV-A照射时间的关系，评估了用于气相甲苯降解的等离激元光催化剂的稳定性和动力学。通过在光催化剂上涂覆银，或在其下覆盖二氧化硅保护的或未保护的银，来产生等离子样品。使用有限差分时域模拟对样本进行建模并进行表征。实验结果表明，与TiO ₂相比，涂银的光催化剂以及在未保护的银上形成的光催化剂最初显示出较高的TVOC降解速率。，但由于银的氧化而使其失活相对较快。与未保护（即未涂覆）的银上的光催化剂相比，在二氧化硅保护（即涂覆有二氧化硅的银）上形成的光催化剂显示出更高的稳定性，并且反应速率常数提高了50％以上，表观量子产率提高了三倍以上在所述非等离激元的对照样品（的TiO ₂超过的SiO ₂）。这项研究的结果表明，二氧化硅层可以帮助减缓二氧化硅纳米颗粒的结垢，并且二氧化硅包覆的银纳米颗粒不仅有助于提高整体反应速率，而且还可以加快光催化过程中不定形碳从光催化剂表面的释放。反应的初始阶段。

图形摘要