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. 2024 Mar 26;58(12):5598-5605. doi: 10.1021/acs.est.4c00584. Epub 2024 Mar 11.
Metal-free carbon-based catalysts are attracting much attention in the low-temperature selective catalytic reduction of NO with NH (NH-SCR). However, the mechanism of the NH-SCR reaction on carbon-based catalysts is still controversial, which severely limits the development of carbon-based SCR catalysts. Herein, we successfully reconstructed carbon-based catalysts through oxidation treatment with nitric acid, thereby enhancing their low-temperature activity in NH-SCR. Combining experimental results and density functional theory (DFT) calculations, we proposed a previously unreported NH-SCR reaction mechanism over carbon-based catalysts. We demonstrated that C-OH and C-O-C groups not only effectively activate NH but also remarkedly promote the decomposition of intermediate NHNO. This study enhances the understanding of the NH-SCR mechanism on carbon-based catalysts and paves the way to develop low-temperature metal-free SCR catalysts.
无金属碳基催化剂在低温选择性催化还原 NO 与 NH（NH-SCR）中引起了广泛关注。然而，碳基催化剂上 NH-SCR 反应的机理仍存在争议，这严重限制了碳基 SCR 催化剂的发展。在此，我们通过用硝酸进行氧化处理成功地对碳基催化剂进行了重构，从而提高了它们在 NH-SCR 中的低温活性。结合实验结果和密度泛函理论（DFT）计算，我们提出了一个以前未报道的碳基催化剂上的 NH-SCR 反应机理。我们证明了 C-OH 和 C-O-C 基团不仅能有效地活化 NH，而且还能显著促进中间产物 NHNO 的分解。本研究增强了对碳基催化剂上 NH-SCR 机理的理解，并为开发低温无金属 SCR 催化剂铺平了道路。
