3D Micro Porous Cobalt−Iron−Phosphorus Electrocatalyst for Overall Water Splitting

Abstract

3D Co-Fe-P microstructure based on electrodeposition was synthesized for high performance oxygen and hydrogen evolution reaction catalysts. Preferentially, Fe/Co ratio of Co-Fe-P film was optimized to 1.1 and exhibited the highest activity for the oxygen evolution. It is related with the transfer of the valence electron from Co to Fe and P. Based on these characteristics and Cu foam microstructure, 3D porous Co-Fe-P foam was fabricated. The Co-Fe-P foam had 94 times larger electrochemical active surface area (ECSA) than the Co-Fe-P film with similar Fe/Co ratios of 1.1, resulting in a high activity for the oxygen evolution reaction (294 mV at 10 mA/cm2) and hydrogen evolution reaction (73 mV at 10 mA/cm2) in 1 M KOH solution. The electrodeposited Co-Fe-P foam itself can be directly used without binder, and microstructure of the electrode can be engineered by controlling the electrodeposition condition, leading to the enlarged ECSA and improved performance. This study offers a facile and controllable synthesis of catalyst and electrode through an easy electrodeposition process.