Chemisorbed oxygen on Au(111) produced by a novel route: Reaction in condensed films of NO₂ + H₂O

We report a facile, low-temperature reaction between condensed-phase NO₂ and H₂O that leads ultimately to the formation of a large concentration (θ₀ = 0.42 monolayers) of adsorbed oxygen adatoms on a Au(111) surface. This reaction represents a novel route to generate surface oxygen on Au that can be utilized in fundamental studies of oxidation catalysis over Au such as low-temperature CO oxidation and the operation of Au converter tubes used in redox chemiluminesence detectors for atmospheric NO_x. Also, this reaction may be relevant to heterogeneous processes occurring on ice particles in stratospheric clouds. This reaction is not specifically catalyzed by the Au(111) surface or by the defects present on the Au surface, and so this reaction may have some general utility for facile oxidation of unreactive surfaces.