Department of Civil, Environmental, and Construction Engineering, Catalysis Cluster for Renewable Energy and Chemical Transformations (REACT), NanoScience Technology Center (NSTC), University of Central Florida, Orlando, Florida 32816, United States.
School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
Environ Sci Technol. 2021 Mar 16;55(6):4017-4026. doi: 10.1021/acs.est.0c08410. Epub 2021 Mar 3.
Investigating catalytic reaction mechanisms could help guide the design of catalysts. Here, aimed at improving both the catalytic performance and SO resistance ability of catalysts in the selective reduction of NO by NH (NH-SCR), an innovative CeO-SiO mixed oxide catalyst (CeSi2) was developed based on our understanding of both the sulfur poisoning and reaction mechanisms, which exhibited excellent SO/HO resistance ability even in the harsh working conditions (containing 500 ppm of SO and 5% HO). The strong interaction between Ce and Si (Ce-O-Si) and the abundant surface hydroxyl groups on CeSi2 not only provided fruitful surface acid sites but also significantly inhibited SO adsorption. The NH-SCR performance of CeSi2 was promoted by an enhanced Eley-Rideal (E-R) mechanism in which more active acid sites were preserved under the reaction conditions and gaseous NO could directly react with adsorbed NH. This mechanism-enhanced process was even further promoted on sulfated CeSi2. This work provides a reaction mechanism-enhanced strategy to develop an environmentally friendly NH-SCR catalyst with superior SO resistance.
研究催化反应机制有助于指导催化剂的设计。在这里，我们基于对硫中毒和反应机制的理解，旨在提高 NH-SCR 中催化剂的催化性能和 SO 抗干扰能力，开发了一种创新性的 CeO-SiO 混合氧化物催化剂（CeSi2）。即使在恶劣的工作条件（含有 500ppm 的 SO 和 5%的 HO）下，CeSi2 也表现出优异的 SO/HO 抗干扰能力。Ce 和 Si 之间的强相互作用（Ce-O-Si）和 CeSi2 表面上丰富的羟基不仅提供了丰富的表面酸性位，而且还显著抑制了 SO 的吸附。NH-SCR 性能的提高是由于增强了 Eley-Rideal（E-R）机制，其中在反应条件下保留了更多的活性酸性位，气态 NO 可以直接与吸附的 NH 反应。在硫酸盐化的 CeSi2 上，这种增强机制的过程得到了进一步的促进。这项工作提供了一种反应机制增强策略，用于开发具有优异 SO 抗干扰能力的环保型 NH-SCR 催化剂。
