Oxygen Reduction and Evolution on Ni-modified Co O (1 1 1) Cathodes for Zn-Air Batteries: A Combined Surface Science and Electrochemical Model Study.

The performance of structurally and chemically well-defined Ni-free and Ni-modified single-crystalline Co O (1 1 1) thin-film electrodes in the oxygen reduction and evolution reactions (ORR and OER) was investigated in a combined surface science and electrochemistry approach. Pure and Ni-modified Co O (1 1 1) film electrodes were prepared and characterized under ultrahigh-vacuum conditions by scanning tunneling microscopy and X-ray photoelectron spectroscopy. Both Ni decoration (by post-deposition of Ni) and Ni doping (by simultaneous vapor deposition of Ni, Co, and O ) induced distinct differences in the base cyclic voltammograms in 0.