Catalytic activity atlas of ternary Co-Fe-V metal oxides for the oxygen evolution reaction

摘要

The sluggish oxygen evolution reaction (OER) is a crucial limiting factor in many renewable energy conversion and storage devices. Multi-metal oxides have been explored as efficient electrocatalysts for the OER; however, the ideal elemental composition for multi-metal oxides is unknown. We first performed density functional theory calculations, which predicted that Co oxyhydroxides doped with Fe and V have excellent catalytic activity. We synthesized a series of amorphous Co-Fe-V ternary metal oxides with a precisely controlled metal molar composition (denoted as CoaFebVcOx, wherea+b+c= 10), uniformly distributed elements and identical morphologies by using Prussian blue analogues (PBAs) as novel metal precursors. A systematic investigation was carried out to establish correlations between the elemental compositions and the OER activity for CoaFebVcOx, resulting in a comprehensive catalytic activity atlas of ternary Co-Fe-V metal oxides for the OER, which can serve as a roadmap for electrocatalyst development. In particular, Co(3)Fe(4)V(3)O(x)with an elemental composition of Co : Fe : V = 3 : 4 : 3 shows the best performance, with an overpotential of merely 249 mV to reach a current density of 10 mA cm(-2), and a low Tafel slope of 41 mV dec(-1), outperforming a commercial IrO(x)catalyst. X-ray photoelectron spectroscopy analysis reveals strong electronic synergies among the metal cations in CoaFebVcOx. The V and Fe doping can affect the electronic structure of Co to yield nearly optimal adsorption energies for OER intermediates, giving rise to the superior activity. Furthermore, composition-tuneable and uniform PBAs may serve as versatile and efficient metal precursors to produce many more multi-metal oxides for various renewable energy applications.