Photo-assisted selective catalytic reduction (photo-SCR) has been considered as a promising strategy for NOx removal in recent decades. The purpose of the present work was to test the effectiveness of La1–xPrxCoO3, supported on the surface of natural palygorskite (Pal) by a facile sol-gel method, as a photo-SCR for the removal of NOx from wastewaters. The structure, acidity, and the redox property of the prepared La1–xPrxCoO3/Pal nanocomposite were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS), and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations were employed to determine the valence bands. The La1–xPrxCoO3/Pal catalysts were then tested for SCR removal of NOx with the assistance of photo-irradiation. The photo-SCR results revealed that the NOx conversion and the N2-selectivity were greatly improved by this method and reached >95% when carried out at the relatively low temperature of 200°C and with the Pr doping at x = 0.5. The improvements were attributed to the co-precipitation of a PrCoO3 phase as in a solid solution forming a coherent heterojunction of PrCoO3/La0.5Pr0.5CoO3 on the Pal surface.

中文翻译：

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La1–xPrxCoO3/坡缕石纳米复合材料上光辅助催化去除 NOx：Pr 掺杂的作用

近几十年来，光辅助选择性催化还原 (photo-SCR) 被认为是一种很有前景的 NOx 去除策略。本工作的目的是测试 La1-xPrxCoO3 的有效性，通过简便的溶胶-凝胶方法支持在天然坡缕石 (Pal) 表面，作为光 SCR 去除废水中的 NOx。使用 X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、紫外-可见漫反射光谱仪对制备的 La1-xPrxCoO3/Pal 纳米复合材料的结构、酸度和氧化还原性能进行了表征。 UV-Vis DRS) 和 X 射线光电子能谱 (XPS)。采用密度泛函理论 (DFT) 计算来确定价带。然后在光照射的辅助下测试 La1-xPrxCoO3/Pal 催化剂对 NOx 的 SCR 去除。photo-SCR 结果表明，通过这种方法，NOx 转化率和 N2 选择性大大提高，并在 200°C 的相对较低温度下和 Pr 掺杂在 x = 0.5 下进行时达到 >95%。这些改进归因于 PrCoO3 相在固溶体中的共沉淀，从而在 Pal 表面上形成了 PrCoO3/La0.5Pr0.5CoO3 的相干异质结。