842 research outputs found
Hydroxylation of Platinum Surface Oxides Induced by Water Vapor
With its high stability and well-tuned binding strength for adsorbates, platinum is an excellent catalyst for a wide range of reactions. In applications like car exhaust purification, the oxidation of hydrocarbons, and fuel cells, platinum is exposed to highly oxidizing conditions, which often leads to the formation of surface oxides. To reveal the structure of these surface oxides, the oxidation of Pt in O2 has been widely studied. However, in most applications, H2O is also an important or even dominant part of the reaction mixture. Here, we investigate the interaction of H2O with Pt surface oxides using near-ambient-pressure X-ray photoelectron spectroscopy. We find that reversible hydroxylation readily occurs in H2O/O2 mixtures. Using time-resolved measurements, we show that O–OH exchange occurs on a time scale of seconds
Structural model for transient Pt oxidation during fuel cell start-up using electrochemical X-ray photoelectron spectroscopy
Catalysis and Surface Chemistr
X-ray absorption and photoemission studies of the active oxygen for ethylene epoxidation over silver
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