Powder metallurgy synthesis of porous Ni-Fe alloy for oxygen evolution reaction and overall water splitting

Abstract

Developing inexpensive and high efficient catalysts is essential for generating oxygen and hydrogen via water splitting. Herein, based on powder metallurgy, a Ni-Fe based compound (Ni8Fe2 alloy) with unique porous structure and controllable phase has been designed and synthesized. Without using a solvent or template, the alloy exhibits a porous structure with uniformly distributed multi-phase. The obtained Ni8Fe2 alloy exhibits an efficient oxygen evolution reaction (OER) performance and good long-term stability in alkaline electrolyte (i.e. 1.0 M KOH). Additionally, an alkaline water splitting device has been assembled using porous Ni8Fe2 alloy as both anode and cathode materials. The system requires a cell voltage of 1.65 V to reach the 10 mA cm−2 current density for overall water splitting and maintains good stability for 25 h. The efficient electrocatalytic performance of the Ni8Fe2 alloy is owing to the unique porous microstructure, increased active sites and accelerated charge transfer. Consequently, the reaction kinetics of OER are significantly promoted.