Research status and outlook of molecular sieve NH3-SCR catalysts

Abstract

NH3-SCR technology is a highly efficient denitrification technology that is widely used in the purification of diesel exhaust and coal-fired flue gas from thermal power plants. Molecular sieve catalysts have been extensively investigated for their high activity and selectivity. In this review, the preparation, structure, active sites and some resistances of Cu-based molecular sieve catalysts, Fe-based molecular sieve catalysts and composite metal molecular sieve catalysts are systematically investigated for relevant elaboration. In addition, the NH3-SCR reaction mechanism over the catalysts is also explained. With the increasingly stringent requirements of NOx emission, we need to develop more efficient catalysts. This paper provides a summary of the hydrothermal aging stability and the inorganic element (S / P / Alkali and alkaline earth metal) poisoning mechanisms as well as the influence of the preparation process in the molecular sieve catalysts, and we hope this review contributes to the development of molecular sieve catalysts.