Enhancing the trifunctional electrocatalytic activity of Fe-Co-Ni multi-component alloys using a zinc dealloying strategy

Abstract

The frequently-used Al dealloying technology is difficult to apply in the alloy electrodes prepared by the electrodeposition method. To address this issue, Zn with the excellent electrodeposition performances in aqueous solution is innovatively employed as a dealloying element in this work. Firstly, a simple electrodeposition method is used to synthesize a multi-component alloy containing Fe, Co, Ni, Cr, Mo, and Zn (NF-FCNCMZ_0.05). The Zn is subsequently removed through dealloying in an alkaline solution, resulting in a multi-component alloy (NF-FCNCMZ_0.05-D). NF-FCNCMZ_0.05-D demonstrates the excellent trifunctional electrocatalytic activity, achieving the potentials of 1.50, 0.083, and 1.34 V vs. RHE at a current density of 100 mA cm⁻² for oxygen evolution (OER), hydrogen evolution (HER), and methanol oxidation reaction (MOR), respectively. Furthermore, the electrolyzers using NF-FCNCMZ_0.05-D as both cathode and anode for alkaline water and seawater splitting exhibit the low voltages. Replacing OER with MOR further reduces the water splitting voltage to 1.51 V at 100 mA cm⁻², enabling the high selectivity (98.7 %) of formate production. This work provides a new strategy for enhancing the electrocatalytic performances of multi-component alloys prepared by electrodeposition.