A theoretical model for methanol formation from carbon monoxide and hydrogen on zinc oxide surfaces

Models are developed for the polar (0001) and nonpolar (1010) surfaces of ZnO in order to consider methanol formation from adsorbed carbon monoxide and hydrogen atoms. The heats of adsorption of H/sub x/CO and OH/sub x/CO (x = 0-3) species involved in methanol formation are computed to determine the enthalpy changes of reaction. Reaction sequences involving formyl or formate intermediates are considered. The reaction mechanism is catalyzed by the Cu/sup +/ to proceed through a methoxy intermediate on Cu/sup +//ZnO with a lower of the energy pathway. The ZnO surfaces are poor donors and function primarily as acceptors of electron density from CO. The donor role of Cu/sup +/ is demonstrated on the polar surface by increasing the heat of adsorption of acceptor adspecies and decreasing the heat of adsorption of donor adspecies. 22 references, 8 figures, 4 tables.