Simultaneous integration of low-level rhenium (Re) doping and nitrogen-functionalized 3D carbon backbone into nickel-iron hydroxide (NiFeOH) to amplify alkaline water electrolysis at high current densities

Abstract

Industrial-scale water electrolysis is still limited because of the evolution process of oxygen requires a strict limit of overpotential (≤300 mV) to realize a current density of 500 mA cm-2. To accelerate sluggish oxygen evolution reaction (OER) process, we fabricated an extremely efficient oxygen-evolving hybrid catalyst by incorporating low-level rhenium content and nitrogen doped carbon cloth with NiFeOH.This hybrid catalyst, associated with a modified electronic structure of NiFeOH under the influence of N-CC and Re, generates a synergistic catalytic effect that can enhance water dissociation and intermediate hydrogen atom (H*) adsorption rate. Re-NiFeOH/N-CC exhibits high hydroxyl oxidation activity (300 mV for J300 , 320 mV for J500) and this in turn satisfies the commercial criteria of alkaline water electrolysis by delivering a high current density of 300 mA cm-2 at a cell voltage of 1.88 V. The high robustness of Re-NiFeOH/N-CC catalyst in the multistep stability test (in 1 M KOH electrolyte) proves its efficacy in electricity-driven large-scale hydrogen production.