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

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 NO_x 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.