“Reduction-aggregation” strategy to construct a low-cost and high-efficiency Ag/Al2O3 catalyst for NH3-SCO

Abstract

Ammonia (NH3) is the main alkaline gas in the atmosphere and neutralizes acidic gases to form haze. Ag-based catalysts are widely used in the field of ammonia selective catalytic oxidation (NH3-SCO) due to their low cost and high efficiency. However, Ag-based catalysts with high activity at low temperatures are usually loaded with large amounts of Ag. To further reduce the cost of Ag-based catalysts, we used a “reduction-aggregation” strategy to aggregate isolated Ag atoms that were highly dispersed into Ag nanoparticles (AgNPs) so that more active centers could be exposed under low Ag loading conditions. Significant AgNPs size effects in the NH3-SCO reaction were found, including the effect of AgNPs size on catalyst activity and stability. Finally, novel Ag/Al2O3 catalysts with high efficiency and stability were developed at a low Ag loading of 1 wt % and achieved better NH3-SCO performance than 10% Ag/Al2O3, which significantly reduced the catalyst cost.