RESUMO
The introduction of a small amount of TiO2 changes the surface properties of the SiO2 material, which further significantly affects the dispersion state of Ti(SO4)2. The differences in acidity and redox caused by the distribution of Ti(SO4)2 are closely related to the catalyst performance for dimethyl ether (DME) oxidation. In particular, the calcination temperature could adjust the surface hydroxyl content of TiO2/SiO2, which determines the dispersion of Ti(SO4)2 components, resulting in distinct acid sites and Ti valence. The most number of weak acid sites and the highest proportion of Ti3+/Ti4+ in the Ti(SO4)2/TS-400 °C catalyst remarkably promote the formation of dimethoxymethane (DMM) from 14.4% to 82.6%, compared to the Ti(SO4)2/SiO2 catalyst.