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. 2021 May 18;55(10):6995-7003. doi: 10.1021/acs.est.0c08214. Epub 2021 Mar 8.
Mn-based oxides exhibit outstanding low-temperature activity for the selective catalytic reduction of NO with NH (NH-SCR) compared with other catalysts. However, the underlying principle responsible for the excellent low-temperature activity is not yet clear. Here, the atomic-level mechanism and activity-limiting factor in the NH-SCR process over Mn-, Fe-, and Ce-based oxide catalysts are elucidated by a combination of first-principles calculations and experimental measurements. We found that the superior oxidative dehydrogenation performance toward NH of Mn-based catalysts reduces the energy barriers for the activation of NH and the formation of the key intermediate NHNO, which is the rate-determining step in NH-SCR over these oxide catalysts. The findings of this study advance the understanding of the working principle of Mn-based SCR catalysts and provide a fundamental basis for the development of future generation SCR catalysts with excellent low-temperature activity.
与其他催化剂相比，锰基氧化物在选择性催化还原 NO 与 NH（NH-SCR）中表现出优异的低温活性。然而，导致其优异低温活性的基本原理尚不清楚。在此，通过第一性原理计算和实验测量相结合，阐明了 Mn、Fe 和 Ce 基氧化物催化剂上 NH-SCR 过程中的原子级机理和活性限制因素。我们发现，Mn 基催化剂对 NH 的优异氧化脱氢性能降低了 NH 的活化和关键中间产物 NHNO 的形成的能垒，这是这些氧化物催化剂上 NH-SCR 的速控步骤。本研究的结果增进了对 Mn 基 SCR 催化剂工作原理的理解，并为开发具有优异低温活性的新一代 SCR 催化剂提供了基础。
