OPTIMISATION OF CATALYST ALLOY SURFACES

摘要

The present invention provides methods for altering the surface composition of an alloy, which comprise the following steps: a)providing an alloy comprising at least two metals; b)exposing said alloy to an oxidising agent whereby to cause oxidation of at least one of said metals to form at least one metal oxide on a surface of the alloy; and c)exposing the resulting alloy to a reducing agent whereby to reduce said metal oxide; wherein said metals are each independently selected from groups 6, 7, 8, 9, 10 and 11 of the Periodic table and include at least one metal selected from platinum (Pt), palladium (Pd), rhodium (Rh) and ruthenium (Ru), and further wherein said alloy is not a platinum-rhodium (Pt-Rh) alloy. Surface- modified alloys obtainable by such methods are also provided by the invention and find particular use as catalysts and in catalytic converters and fuel cells.