富氧条件下氢气选择催化还原汽车尾气氮氧化物的研究进展

汽车尾气中的氮氧化物（NO _x ）是大气主要污染物之一，严重危害了环境和人类健康。选择催化还原（SCR）消除技术是一种在富氧条件下能够高选择性消除NO _x 的技术。氢气选择催化还原氮氧化物（H₂-SCR）由于其低温高活性的优势备受关注。目前H₂-SCR研究中以Pt和Pd作活性组分催化剂使用较多，其中Pt基催化剂的研究最为广泛，本文介绍了催化剂载体类型、载体性质（如酸碱性、比表面积、孔道结构）、助剂和预处理方式等对催化活性的影响及影响机制，综述了反应条件参数（如反应气中O₂和NO₂浓度，杂质气体H₂O和SO₂）对催化剂催化活性的影响，认为反应气组分的影响在于各组分在催化剂上的竞争吸附以及对催化剂活性位的影响，最后展望了面向实际应用H₂-SCR技术未来的研究方向。

Research progresses on selective catalytic reduction of NO x from automobile exhaust by hydrogen in excess oxygen

Nitrogen oxide (NO _x ) from automobile exhaust is one of the main pollutants in the atmosphere，which is very harmful to environment and human health. Selective catalytic reduction (SCR) of NO _x is a technology for high selective removal of NO _x in presence of excess oxygen. H₂-SCR has attracted much attention due to its advantages of high activity at low temperature. At present, Pt and Pd are widely used as active component of the catalysts used in H₂-SCR. Among them, Pt-supported catalysts have been the most widely studied. The influence and the corresponding mechanism of the types of the catalyst support, carrier properties (such as acid-base properties, BET surface area and pore structure), additive and pretreatment methods on the catalytic performance were summarized. Then, the effect of reaction condition parameters (such as concentration of O₂ and NO₂ in reactant gas mixture, coexisting gas of H₂O and SO₂ in practical processes) on the catalytic activity were reviewed. It was found that the impact of reaction gas component on the catalytic activity is determined by their competitive adsorption on catalyst’s surface and their influence on the active sites. Finally, the future research direction of H₂-SCR for practical application was prospected.