Aluminium-induced component engineering of mesoporous composite materials for low-temperature NH3-SCR

Ge Li,Dehai Lin,Jiali Zhou,Yun Wang,Chunlin Zhao,Hongyan Wang,Jing Ma,Qi Sun,Zhihua Han,Ziran Ma,Faquan He,Baodong Wang

doi:10.1038/s42004-020-0311-4

Abstract

Supported Mn2O3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR). However, its controlled synthesis is challenging when the supporting material is the conventional pure silicon SBA-15 mesoporous molecular sieve. Here we show that silicon and aluminium in fly ash, the solid waste produced by coal-fired power plants, can be used to synthesize an Al-SBA-15 mesoporous molecular sieve support, which can guide the growth of Mn2O3 in the as-synthesized Fe-Mn/Al-SBA-15 NH3-SCR catalyst. Its superior catalytic performance is demonstrated by the high NOx conversion (≥90%) and selectivity (≥86%) at low temperatures (150–300 °C). The combined theoretical and experimental results reveal that the introduction of Al induces the growth of Mn2O3 catalysts. Our findings, therefore, provide a strategy for the rational design of low-temperature NH3-SCR catalysts through dopant-induced component engineering of composite materials.

Highlights

Supported Mn2O3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR)
Since the pH value is crucial for the aluminum salt hydrolysis and Si–O–Al bonds formation, we first investigated the effect of the pH value on the synthesis of fly ash-derived Al-SBA-15 mesoporous molecular sieves (MMS). 1 g of the fly ash-derived Si-SBA-15 MMS and 1 g of fly ash-derived
X-ray diffraction (XRD) patterns of the Al-SBA-15 MMS prepared at different pH values

Summary

Introduction

Supported Mn2O3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR). Its controlled synthesis is challenging when the supporting material is the conventional pure silicon SBA-15 mesoporous molecular sieve. We show that silicon and aluminium in fly ash, the solid waste produced by coalfired power plants, can be used to synthesize an Al-SBA-15 mesoporous molecular sieve support, which can guide the growth of Mn2O3 in the as-synthesized Fe-Mn/Al-SBA-15 NH3SCR catalyst. Its superior catalytic performance is demonstrated by the high NOx conversion (≥90%) and selectivity (≥86%) at low temperatures (150–300 °C). The 11.2Fe-11Mn/ SBA-15 catalyst exhibits high NH3-SCR activities at 150–250 °C.

Methods

Results

Conclusion