Coadsorption-induced recombination of surface hydroxyl species (OD(a)) on Ni (110) was verified by infrared reflection absorption spectroscopy (IRAS) and temperature programmed desorption (TPD). The O-D stretching mode of the surface hydroxyl species appeared at 2650 cm-1 at 173 K on D2O/ONi (110) surface. The hydroxyl species were thermally recombined and desorbed as D2O from the Ni (110) surface at 350 K. The recombination of the OD species to water (2731 and 2567 cm-1), was also observed at a lower temperature (117 K) when CO was coadsorbed. This OD recombination induced by CO adsorption is considered to result from a strong effect of coadsorbed CO, which lowers the reaction temperature from 350 to 117 K.
