An excellent OER electrocatalyst of cubic SrCoO3−δ prepared by a simple F-doping strategy

Abstract

Driven by the increasing global energy demand, the development of innovative energy conversion and storage systems is becoming more and more urgent. As one of the attractive means, water splitting has attracted widespread attention because of its great potential in storing electricity in the form of chemical fuel which also makes it a promising solution to the utilization of non-grid electricity generated by solar or wind. The oxygen evolution reaction (OER) is generally deemed as the key rate-limiting step of water splitting, and thus studying efficient OER electrocatalysts with a low overpotential and good stability is of vital importance. Here, we successfully prepared an OER catalyst with excellent electrochemical performance through a simple anion doping. Firstly, a stable cubic perovskite SrCoO_3−δ was prepared by anion F-doping instead of traditional A and/or B site doping. Secondly, SrCoO_2.85−δF_0.15 demonstrates excellent OER activity superior to its parent hexagonal compound H-Sr₂Co₂O₅ and those perovskites prepared via complicated A- and/or B-site doping. DFT calculations and XPS investigations reveal that the cubic structure and the highly oxidative oxygen species (O₂²⁻/O⁻) via F⁻ doping jointly contribute to the better OER properties of SrCoO_2.85−δF_0.15. Our work brings forth a promising strategy to stabilize cubic structures from hexagonal ones via a simple anion doping strategy, which may open a new avenue for the development of even more effective OER catalysts and may be applied in many other fields related to structure transformation, in addition to energy and catalysis fields.