The mechanism of oxygen activation on single Pt-atom doped SnO2(110) surface

SnO2, as a highly stable and carbon-free catalyst, is widely used in proton exchange membrane fuel cell as support. In order to shed light on the mechanism of oxygen reduction reaction on SnO2, the activation of the oxygen atom and molecule on undoped and Pt-doped SnO2 was investigated using the first-principles method in this study. We found that: (a) the Pt dopants in the SnO2(110) surfaces are positively charged; (b) the O-vacancy sites are the most preferable for the adsorption of molecular oxygen; (c) O− species, the most reactive form of oxygen, are easy to be formed through the activation of molecular oxygen on the O-defect sites of the Pt-doped SnO2 surface; and (d) the synergetic effects of Pt dopant and O-vacancy would be the key to the O2 activation. The current results shed light on the activation mechanism of oxygen species on undoped and Pt-doped SnO2 supports.