Abstract：
Mn-based catalysts are promising candidates for eliminating harmful nitrogen oxides (NOx) via selective catalytic reduction with ammonia (NH3-SCR) due to their inherent strong redox abilities. However, poor water tolerance and low N2 selectivity are still the main limitations for practical applications. Herein, we succeeded in preparing an active catalyst for NH3-SCR with improved water tolerance and N2 selectivity based on protecting MnOx with a secondary growth of a hydrophobic silicalite-1. This protection suppressed catalyst deactivation by water adsorption. Interestingly, impregnating MnOx on MesoTS-1 followed by silicalite-1 protection allowed for a higher dispersion of MnOx species, thus increasing the concentration of acid sites. Consequently, the level of N2O formation is decreased. These improvements resulted in a broader operating temperature of NOx conversion and a modification of the NH3-SCR mechanism. Diffuse reflectance infrared Fourier transform spectroscopy analysis revealed that unprotected Mn/MesoTS-1 mainly followed the Eley-Rideal mechanism, while Mn/MesoTS-1@S1 followed both Langmuir-Hinshelwood and Eley-Rideal mechanisms.
摘要：
Mn基催化剂是通过用氨选择性催化还原(NH3-SCR)消除有害氮氧化物(NOx)的有希望的候选物,因为它们固有的强氧化还原能力。然而,耐水性差和低N2选择性仍然是实际应用的主要限制。在这里，我们成功地制备了一种用于NH3-SCR的活性催化剂，该催化剂具有改善的耐水性和N2选择性，基于用疏水性硅沸石-1的二次生长保护MnOx。这种保护抑制了由于水吸附引起的催化剂失活。有趣的是,在MesoTS-1上浸渍MnOx，然后进行硅质岩-1保护，从而使MnOx物种具有更高的分散性，从而增加酸性位点的浓度。因此,N2O形成水平降低。这些改进导致更宽的NOx转化操作温度和NH3-SCR机制的改进。漫反射红外傅里叶变换光谱分析表明，未保护的Mn/MesoTS-1主要遵循Eley-Rideal机制，而Mn/MesoTS-1@S1遵循Langmuir-Hinshelwood和Eley-Rideal机制。
