Hexagonal perovskite Sr6(Co0.8Fe0.2)5O15 as an efficient electrocatalyst towards the oxygen evolution reaction

Lianwei Wei; Jiaping Hu; Huimin Liu; Wanqun Zhang; Hui Zheng; Shusheng Wu; Kaibin Tang

doi:10.1039/d2dt00706a

Hexagonal perovskite Sr₆(Co_0.8Fe_0.2)₅O₁₅ as an efficient electrocatalyst towards the oxygen evolution reaction

Dalton Trans. 2022 May 10;51(18):7100-7108. doi: 10.1039/d2dt00706a.

Authors

Lianwei Wei^{1

2}, Jiaping Hu^{1

2}, Huimin Liu^{1

2}, Wanqun Zhang³, Hui Zheng^{1

2}, Shusheng Wu^{1

2}, Kaibin Tang^{1

2}

Affiliations

¹ Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, P. R. China. kbtang@ustc.edu.cn.
² Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China.
³ Chemistry Experiment Teaching Center, University of Science and Technology of China, Hefei, 230026, P. R. China.

PMID: 35451444
DOI: 10.1039/d2dt00706a

Abstract

The high overpotential required for the oxygen evolution reaction (OER)-due to the transfer of four protons and four electrons-has greatly hindered the commercial viability of water electrolysis. People have been committed to the development of alternative precious metal-free OER electrocatalysts, especially electrocatalysts for alkaline media. In this study, we report the application of Sr₆(Co_0.8Fe_0.2)₅O₁₅ (SCF-H) perovskite oxide with a hexagonal phase structure in the field of OER electrocatalysis. Synthesized by a simple and universal sol-gel method, the SCF-H perovskite oxide shows prominent OER activity with an overpotential of 318 mV at a current density of 10 mA cm^-2 and a Tafel slope of only 54 mV dec^-1, which is significantly better than the cubic phase structure SrCo_0.8Fe_0.2O_3-δ (SCF-C), benchmark noble-metal oxide RuO₂ and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF). Compared with cubic SCF-C, the hexagonal SCF-H perovskite oxide has abundant surface oxygen species (O₂^2-/O^-), a faster charge transfer rate, and a higher electrochemical surface area. In addition, the DFT calculation results show that the center of the O p-band of SCF-H is closer to the Fermi level than that of SCF-C, which leads to the better OER activity of SCF-H. This work finds that the new hexagonal structure perovskite may become a promising OER electrocatalyst.