Oxidative dehydrogenation of methanol to formaldehyde on electrolytic silver catalyst modified with iodides

Iodides, especially CH3I, were used as modifiers in the oxidative dehydroge nation of methanol to formaldehyde over electrolytic silver catalyst. The y ield of formaldehyde was as high as 93% at 98% conversion of CH3OH for the I-modified catalyst, while it was only 85% at 94% conversion without I-modi fication. The optimum reaction conditions were determined and the interacti on between the silver surface and the iodide additive was investigated by m eans of XPS and SEM. The chemisorbed iodine atoms on the silver surface cau sed a decrease of the surface concentration of atomic oxygen species and pr evented the complete oxidation of CH3OH to CO2. (C) 1998 Elsevier Science B .V. All rights reserved.