Water dissociation on clean and boron-modified single-crystal Ni-3(Al,Ti) (110) surfaces

The interaction of water vapor with clean and boron-modified Ni-3(Al,Ti) su rfaces was studied with temperature-programmed desorption, X-ray photoemiss ion, and Auger electron spectroscopy. Thermal desorption results indicate t hat water dissociates on clean boron-free Ni-3(Al,Ti) (110) surfaces, resul ting in hydrogen evolution at similar to 400 K. X-ray photoemission studies show that water dissociation occurs above 190 K. Hydrogen desorption at si milar to 400 K is completely suppressed by boron adsorption at a coverage o f about 0.3 monolayer. Anger and X-ray photoemission studies on boron-modif ied Ni-3(Al,Ti) (110) surfaces show that boron reacts with water to form hy droxyl at 130-190 K. Hydrogen desorption occurs at similar to 950 K from bo ron-modified Ni-3(Al,Ti) (110) surfaces, indicating strong B-H bonding.