The catalytic decomposition of methanol on iron foil: I. Steady state flux experiments with photoelectron spectroscopy

The elementary steps of the catalytic decomposition of methanol on polycrystalline iron are investigated and those intermediates which kinetically control the reaction rate are identified over the tempeature range from 90 to 870 K. At temperatures below 100 K condensation of methanol at the surface occurs, at about 130 K dissociation begins and a stable methoxy species is formed bound via oxygen to the surface. The methoxy species is inclined to a lying position with increasing temperature; further decomposition finally leads to CHO ads that above 350 K is split into CH ads and O ads. The threshold energy of the dissociation of CHO ads is measured to be 79.8 kJ mol . At temperatures above 450 K apart from CH ads the adsorbed species are atomic only. At temperatures above 700 K the reaction channels to form CO and H 2 are open, which products are formed out of atomic intermediates.