Synthesis from a layered double hydroxide precursor for a highly efficient oxygen evolution reaction

Abstract

Transition metal selenides are recognized as ideal substitutes for RuO₂ and IrO₂ toward the oxygen evolution reaction (OER). Herein, a selenide hybrid consisting of Co₃Se₄ and FeSe₂ was prepared successfully by a facile one-step hydrothermal method using CoFe-layered double hydroxide nanosheets as the precursor. Electrochemical tests on the rotating disk electrode demonstrate that the hybrid possesses good performance for the OER during water splitting. The Co₃Se₄&FeSe₂ catalyst can achieve an overpotential as low as 280 mV at 10 mA cm⁻² (close to RuO₂) with a Tafel slope of 51 mV dec⁻¹. Such OER activity is also better than those of the majority of the as-reported metal selenide catalysts. It could be attributed to the high electrocatalytic activity of Co₃Se₄ and the synergistic effect between the two metal selenides, which reduce the reaction energy barrier effectively. Long term stability tests show that the sample can last for 24 hours without significant attenuation. Therefore, this work not only provides a facile synthesis method for metal selenides from LDH precursors, but also supplies an efficient hybrid electrocatalyst as a promising candidate for water oxidation.