Introduction of TiO 2 enhancing the catalytic performance of Ti(SO 4 ) 2 /SiO 2 for dimethyl ether oxidation.

The introduction of a small amount of TiO 2 changes the surface properties of the SiO 2 material, which further significantly affects the dispersion state of Ti(SO 4 ) 2 . The differences in acidity and redox caused by the distribution of Ti(SO 4 ) 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 TiO 2 /SiO 2 , which determines the dispersion of Ti(SO 4 ) 2 components, resulting in distinct acid sites and Ti valence. The most number of weak acid sites and the highest proportion of Ti 3+ /Ti 4+ in the Ti(SO 4 ) 2 /TS-400 °C catalyst remarkably promote the formation of dimethoxymethane (DMM) from 14.4% to 82.6%, compared to the Ti(SO 4 ) 2 /SiO 2 catalyst.