Park Eun Duck
Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea.
Department of Chemical Engineering, Ajou University, Suwon 16499, Republic of Korea.
Molecules. 2024 Sep 23;29(18):4506. doi: 10.3390/molecules29184506.
Selective catalytic reduction of nitrogen oxides (NO) with ammonia (NH-SCR) has been implemented in response to the regulation of NO emissions from stationary and mobile sources above 300 °C. However, the development of NH-SCR catalysts active at low temperatures below 200 °C is still needed to improve the energy efficiency and to cope with various fuels. In this review article, recent reports on low-temperature NH-SCR catalysts are systematically summarized. The redox property as well as the surface acidity are two main factors that affect the catalytic activity. The strong redox property is beneficial for the low-temperature NH-SCR activity but is responsible for NO formation. The multiple electron transfer system is more plausible for controlling redox properties. HO and SO, which are often found with NO in flue gas, have a detrimental effect on NH-SCR activity, especially at low temperatures. The competitive adsorption of HO can be minimized by enhancing the hydrophobic property of the catalyst. Various strategies to improve the resistance to SO poisoning are also discussed.
为应对固定源和移动源在300℃以上氮氧化物（NO）排放的监管，已实施了用氨选择性催化还原氮氧化物（NH-SCR）。然而，仍需要开发在200℃以下低温下具有活性的NH-SCR催化剂，以提高能源效率并应对各种燃料。在这篇综述文章中，系统总结了关于低温NH-SCR催化剂的最新报道。氧化还原性能以及表面酸度是影响催化活性的两个主要因素。强氧化还原性能有利于低温NH-SCR活性，但会导致NO生成。多电子转移系统对于控制氧化还原性能更具合理性。烟气中经常与NO同时存在的H₂O和SO₂对NH-SCR活性有不利影响，尤其是在低温下。通过增强催化剂的疏水性可以使H₂O的竞争吸附最小化。还讨论了提高抗SO₂中毒能力的各种策略。
