Division of Biotechnology, Advanced Institute of Environment and Bioscience, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, 54596, Korea.
Photochem Photobiol Sci. 2019 May 15;18(5):1092-1100. doi: 10.1039/c8pp00460a.
This study presents the first report on the photocatalytic inactivation mechanism for a Salmonella typhimurium pathogen by visible-light active CuxO loaded rhodium-antimony co-doped TiO2 nanorods (CuxO/Rh-Sb-TiO2 NRs) under visible light irradiation (cutoff filter, λ ≥ 420 nm). Remarkably higher pathogenic inactivation of 4 log within 40 min by a CuxO supported Rh-Sb-TiO2 NR photocatalyst was observed. The visible light active photocatalyst mainly produced reduced Cu+ in the lattice of CuxO by charge separation. By this means, photo-generated electrons at the conduction band of Rh-Sb-TiO2 NRs play an important role in reducing Cu2+ to Cu+ through the photocatalytic reduction reaction (PRR), and at the valence band of Rh-Sb-TiO2 NRs, photo-generated holes generate OH˙ radicals through the photocatalytic oxidation reaction (POR). This Cu+ copper species is lethal to microbial pathogens. The inactivation mechanism for the Salmonella typhimurium pathogen was investigated by protein oxidation, HCHO production, and the API-ZYM system. To investigate the role of OH˙ radicals, t-BuOH and MeOH as hole scavengers were used in photocatalytic inactivation reactions. Our experimental results confirmed that the reduced Cu+ species play a major role in bacterial inactivation, while ROS have a major effect on the degradation of organic pollutants.
本研究首次报道了在可见光照射下（截止滤光片，λ≥420nm），负载铜铈氧化物（CuxO）的铑-锑共掺杂二氧化钛纳米棒（CuxO/Rh-Sb-TiO2 NRs）对鼠伤寒沙门氏菌病原体的光催化灭活机制。令人瞩目的是，负载 CuxO 的 Rh-Sb-TiO2 NR 光催化剂在 40 分钟内实现了高达 4 个对数的病原体灭活。可见光活性光催化剂主要通过电荷分离在 CuxO 的晶格中产生还原的 Cu+。通过这种方式，Rh-Sb-TiO2 NRs 导带中的光生电子通过光催化还原反应（PRR）在还原 Cu2+为 Cu+中发挥重要作用，而 Rh-Sb-TiO2 NRs 的价带中，光生空穴通过光催化氧化反应（POR）产生 OH˙自由基。这种 Cu+铜物种对微生物病原体是致命的。通过蛋白质氧化、HCHO 生成和 API-ZYM 系统研究了鼠伤寒沙门氏菌病原体的灭活机制。为了研究 OH˙自由基的作用，在光催化灭活反应中使用 t-BuOH 和 MeOH 作为空穴捕获剂。我们的实验结果证实，还原的 Cu+物种在细菌失活中起主要作用，而 ROS 对有机污染物的降解有主要影响。
