Mn-promoted Ag supported on pure siliceous Beta zeolite (Ag/Beta-Si) for catalytic combustion of formaldehyde

ABSTRACT Catalytic combustion at low temperature has been considered as an effective route for removal of indoor HCHO pollutant, and conventional catalysts are supported noble metal nanoparticles, which are costly for wide applications. Solution of this issue is to use relatively low metal catalysts. Herein, we report that Mn-promoted Ag catalyst supported on pure silica Beta zeolite with a good hydrophobicity is very active for catalytic combustion of HCHO. By optimizing the loadings of Ag and Mn, it is found that 10 wt% Ag with 8 wt% Mn (10%Ag8%Mn/Beta-Si) exhibits highest activity, giving the complete HCHO conversion at around 45 °C, which steadily outperform the temperatures (70-145 °C) for full oxidation of HCHO reported previously. The choice of Ag loading with 10 wt.% is due to the highest exposed surface of Ag sites, and the use of Mn loading with 8 wt% is assigned to the balance of density and mobility for active oxygen species in the catalysts. The strategy combining the hydrophobic supports with optimized active oxygen species might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants in the future.