State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2023 Nov 14;57(45):17577-17587. doi: 10.1021/acs.est.3c05070. Epub 2023 Oct 16.
Commercial vanadium oxide catalysts exhibit high efficiency for the selective catalytic reduction (SCR) of NO with NH, especially in the presence of NO (i.e., occurrence of fast NH-SCR). The high-activity sites and their working principle for the fast NH-SCR reaction, however, remain elusive. Here, by combining spectroscopy, isotopic labeling experiments, and density functional theory (DFT) calculations, we demonstrate that polymeric vanadyl species act as the main active sites in the fast SCR reaction because the coupling effect of the polymeric structure alters the elementary reaction step and effectively avoids the high energy barrier of the rate-determining step over monomeric vanadyl species. This study unveils the high-activity dinuclear mechanism of the NO-involved SCR reaction over vanadia-based catalysts and provides a fundamental basis for developing high-efficiency and low VO-loading SCR catalysts.
商用氧化钒催化剂在 NH 的选择性催化还原（SCR）中表现出高效率，尤其是在存在 NO 的情况下（即快速 NH-SCR 发生）。然而，高活性位点及其快速 NH-SCR 反应的工作原理仍然难以捉摸。在这里，通过结合光谱学、同位素标记实验和密度泛函理论（DFT）计算，我们证明聚合的钒氧物种作为快速 SCR 反应中的主要活性位点，因为聚合结构的耦合效应改变了基本反应步骤，并有效地避免了单体钒氧物种中速率决定步骤的高能量障碍。这项研究揭示了基于氧化钒的催化剂上涉及 NO 的 SCR 反应的高活性双核机制，并为开发高效和低 VO 负载 SCR 催化剂提供了基础。
