Boosting the Dispersity of Metallic Ag Nanoparticles and Ozone Decomposition Performance of Ag-Mn Catalysts via Manganese Vacancy-Dependent Metal-Support Interactions.

Abstract

Ozone (O3) removal has important implications for environmental protection and human health, and Ag-Mn catalysts have shown promising O3 decomposition. Catalysts with Ag supported on porous cube-like α-Mn2O3 (Ag/Mn-C) with high utilization of Ag were prepared by the impregnation method and showed excellent O3 decomposition activity. Physicochemical characterizations demonstrated that metallic Ag nanoparticles (Agn0) were mainly anchored on manganese vacancies, forming Ag-O-Mn bonds between Agn0 and α-Mn2O3-C. The abundant manganese vacancies of α-Mn2O3-C can lead to Agn0 with a smaller particle size and more uniform dispersion, thereby resulting in markedly enhanced O3 decomposition performance compared to Agn0 with a large particle size and uneven distribution on rod-like α-Mn2O3 (Ag/Mn-R). Under a relative humidity of 65% and a space velocity of 1,110,000 h-1, the conversion of 40 ppm O3 over the 2%Ag/Mn-C catalyst within 6 h (98%) at 30 °C was more than twice as high as that of the 2%Ag/Mn-R catalyst (42%). The study provides guidance for the design of highly efficient Ag-based catalysts and the understanding of the microstructure of supported catalysts.