The oxidative dehydrogenation of methanol over a novel Ag/SiO2 catalyst Original Research Article

Catalytic oxidative dehydrogenation of methanol to formaldehyde was carried out over a novel Ag/SiO2 catalyst prepared by the sol-gel method. The yield of formaldehyde over this catalyst was ∼10% higher than that over conventional pumice-supported silver and even ∼1% higher than that over commercial electrolytic silver. When the yields were compared under the optimum conditions, the catalytic activity was measured at 820–920 K, O2/CH3OH molar ratio of 0.35–0.55 and at the space velocity of 1.2×105h−1. The thermal behavior and structure of the catalyst were characterized by TG-DTG, DTA and XRD. It was found that this catalyst was thermally stable and silver was present in a crystalline state. SEM was used to determine its morphology and particle size. The silver particle size range was found to be 200–700 nm. XPS results indicated that two different kinds of silver in aggregated and highly dispersed metallic states, were present on the surface of the catalyst.