THE IMPORTANCE OF WATER IN THE MECHANISM OF METHANOL DECOMPOSITION ON ZNO

The decomposition of methanol on ZnO has been investigated by temperature programmed desorption. The main decomposition products were CO and H-2 With only a small amount of CO2. The influence of water on methanol decomposition has been studied by a series of quantitative co-adsorption experiments. As the amount of coadsorbed water was increased, the CO yield decreased whereas that of the CO2 increased and went through a maximum. This indicated that water and methanol competed for the same adsorption sites. The results suggest that methanol (or dehydrogenated intermediate) reacts with coadsorbed water to form CO2 and H-2. Preadsorbed or residual water give similar results.