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

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.