Mechanochemical redox: a calcination-free process to support CoMnOx catalysts

Abstract

An interesting approach (mechanochemical redox-based loading method, MRL) was introduced to support cobalt manganese oxides on TiO₂, SiO₂ and Al₂O₃. Compared with traditional loading methods (co-precipitation and impregnation), MRL showed better performance in catalyst preparation (solvent- and calcination-free syntheses), specific surface area of the catalyst (84 m² g⁻¹ by MRL, which is much higher than 39–44 m² g⁻¹ by co-precipitation and impregnation methods) and dispersion of active species. In the oxidation reaction of CO, supported CoMnO_x by MRL exhibited good activity (T₁₀₀ = 175 °C) and favorable stability (T = 160 °C, 100 h), better than the control samples (T₁₀₀ = 280 °C by impregnation and T₁₀₀ = 375 °C by co-precipitation). The breakage action, friction heating and instant high pressure by ball milling could contribute to the generation of interstitial porosity, better dispersion of CoMnO_x and the generation of more active sites. Thus, MRL seems like a potential alternative to the synthesis of supported catalysts.