SURFACE-COMPOSITION, STRUCTURAL AND CHEMISORPTIVE PROPERTIES OF RANEY-NICKEL CATALYSTS

The modification of the hydrogen chemisorption properties of Raney nickel by the presence of additives has been studied. It has been found that the addition of sodium hydroxide induces an increase in the amount of reversibly adsorbed hydrogen, responsible for the catalytic activity. XPS and EXAFS show that the additives remove aluminium oxides from the metallic surface, forming large particles of a stable basic aluminate and making a larger area available for chemisorption. The amount of secondary reactions, which occur on acid sites, is also reduced.