Special Chemical Properties of RuOx Nanowires in RuOx/TiO2(110): Dissociation of Water and Hydrogen Production

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 x /TiO 2 (110) surfaces employing scanning tunneling microscopy, photoemission, and density functional calculations. Ruthenium oxide forms unique wirelike structures on top of TiO 2 (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 2 nanowires is <0.05 eV. The presence of easily formable O vacancies in the ruthenium oxide nanowires facilitates the dissociation of water. Furthermore, RuO x /TiO 2 (110) surfaces are able to catalyze the production of hydrogen through the water-gas shift reaction (H 2 O + CO → H 2 + CO 2 ), exhibiting an activity that compares well with the activity found for extended surfaces of copper typically used as benchmarks for studying this reaction.