The adsorption and decomposition of water on Ni(110) studied by electron energy loss spectroscopy

We present an electron energy loss spectroscopy (EELS) study of H2O adsorption on Ni(110). From the lowest exposures water clusters are formed. This is evidenced by the presence of two O–H stretching frequencies at 3350 and 3610 cm−1. The band at 3350 cm−1 is characteristic of hydrogen bonding between water molecules. The band at 3610 cm−1 corresponds to water molecules non‐H‐bonded. At 0.6 L H2O exposure, a third band at 2870 cm−1 is observed. We propose that this band belongs to a O–H ⋅ ⋅ ⋅ Ni stretching mode. From an analysis of the intensities we conclude that cyclic clusters are most probably formed at small coverages. After heating to 200 K we find that water decomposes to form hydroxyl (OH) groups. When the sample is heated to 415 K, the vibrational spectrum shows oxygen as the only product indicative of OH recombination.