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Special chemical properties of RuO x nanowires in RuO x/TiO 2(110): Dissociation of water and hydrogen production

Abstract:

Recently, there has been a strong interest in understanding the role of mixed-metal oxides in catalysts used for the production of hydrogen through the splitting of water. Here, we investigate the structural and chemical properties of RuO <inf>x</inf>/TiO <inf>2</inf>(110) surfaces employing scanning tunneling microscopy, photoemission, and density functional calculations. Ruthenium oxide forms unique wirelike structures on top of TiO <inf>2</inf>(110) which are very reactive toward water dissociation, being able to cleave O-H bonds at a temperature as low as 200 K. The calculated barrier for the dissociation of water on RuO <inf>2</inf> nanowires is <0.05 eV. The presence of easily formable O vacancies in the ruthenium oxide nanowires facilitates the dissociation of water. Furthermore, RuO <inf>x</inf>/TiO <inf>2</inf> (110) surfaces are able to catalyze the production of hydrogen through the water-gas shift reaction (H <inf>2</inf>O + CO → H <inf>2</inf> + CO <inf>2</inf>), exhibiting an activity that compares well with the activity found for extended surfaces of copper typically used as benchmarks for studying this reaction. © 2012 American Chemical Society.