DU Yaping¹， ZHAO Jinyuan¹， ZHANG Jiwen^1，2， JIANG Yong¹

1.School of Materials Science and Engineering & National Institute for Advanced Materials，Tianjin Key Laboratory for Rare Earth Materials and Applications， Research Center for Rare Earth and Inorganic Functional Materials，Nankai University， Tianjin 300350， China； 2.Zhejiang Hailiang Co.， Ltd.， Zhuji 311800， China

Abstract

Significance　Rare earth （RE）-based catalysts have garnered extensive attention in NH₃-selective catalytic reduction （SCR） reactions due to their strong redox capabilities， acidity， and exceptional thermal and chemical stability， particularly in RE oxides. Numerous RE-based NH₃-SCR catalysts have been developed for the ability of RE elements to substitute for other elements. The versatility allows them to function as primary catalyst components， secondary components， and co-catalysts. Understanding the mechanisms of RE elements across various catalyst types， such as metal oxide catalysts and zeolite molecular sieve catalysts， is crucial for developing novel high-performance NH₃-SCR catalysts.

Progress　This paper reviews recent advancements over the past five years in RE-based NH₃-SCR catalysts， focusing on CeO₂-based catalysts， RE-modified MnO_x-based catalysts， and Cu-exchanged zeolite catalysts. Additionally， natural mineral catalysts have garnered increasing attention due to their potential economic value， and the latest research trends in rare earth tailings （RET） catalysts are also reviewed. By analyzing the active sites， reaction pathways， and rate-determining steps of RE-based catalysts， the role of RE elements in different catalysts is summarized as follows：

1） For metal oxide-based and RET catalysts， the enhancement of their activity by RE elements is primarily attributed to the redox properties and acid-base properties of RE compounds and the synergistic effects between RE elements and transition metals. Specifically， electronic interactions between transition metals （Mn， Mo， Ti， etc.） and RE elements （Ce， Sm， Y， etc.） form structural units such as M-O-RE and Ce³⁺-O-Ce³⁺， which regulate the surface acidity and redox capacity of the catalysts， promoting both the acid and redox cycles.

2） For Cu-based zeolite catalysts， the introduction of RE ions increases the bond energy of Al-O in the zeolite framework， stabilizing the framework and improving hydrothermal stability. It also regulates the distribution of Cu active sites on the zeolite framework， promoting the formation of more active and hydrothermally stable Cu sites.

3） The introduction of RE elements enhances the catalyst’s tolerance to SO₂. RE sites preferentially adsorb SO₂， inhibiting sulfate deposition at active sites and preventing their deactivation. Additionally， the formation of an appropriate amount of sulfate on RE sites provides additional acidic sites， further enhancing the catalyst’s activity.

Conclusions and Prospects　Future research can be explored in the following two directions. First， catalyst design should fully consider the complex conditions in actual denitrification processes， including operating temperature， atmosphere， and flue gas/exhaust composition. For example， diesel engine exhaust has high temperatures （~900 ℃） and contains complex hydrocarbons， the cold start emission of vehicles has low temperatures， and the composition of flue gas from different industrial sources， such as power plants and cement plants， varies. Customizing the composition and structure of denitrification catalysts to suit different working conditions will ensure that the catalysts exhibit good tunability and adaptability in various reaction environments， achieving efficient and stable denitrification performance. Second， there is an urgent need to develop and apply new characterization techniques to more comprehensively analyze the structure-performance relationship of catalysts. Such techniques can be used to， for instance， quantify electron transfer between RE and transition metals or capture the potential involvement of 4f electrons distinct to RE during the NH₃-SCR reaction process. This will help reveal the specific mechanisms of RE elements in the catalytic process， providing strong theoretical support for the precise design and performance optimization of catalyst structures. Through continuous efforts in these two directions， RE-based NH₃-SCR catalysts are expected to demonstrate superior performance and broader application prospects in actual denitrification applications.

Keywords： nitrogen oxide； NH₃-selective catalytic reduction； cerium oxide； rare earth-modified catalysts； rare earth tailing

Get Citation:DU Yaping， ZHAO Jinyuan， ZHANG Jiwen， et al. Research advancements in rare earth-based catalysts for NH₃-SCR［J］. China Powder Science and Technology， 2026， 32（2）： 1-15.

Received: 2025-01-03 .Revised: 2025-03-14,Online: 2025-11-17

Funding Project: The research was supported by the National Natural Science Foundation of China （Grant No. 22371131） and the Programme of Introducing Talents of Discipline to Universities （Grant No. B18030）.

DOI：10.13732/j.issn.1008-5548.2026.02.001

CLC No:TB4;TQ324.8                        Type Code: A

Serial No:1008-5548（2026）02-0001-15