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
Sanjib Baran Roy, Euigeol Jung, Kwang Hee Kim, Amar M. Patil, Seung‐Hyun Chun, Jong Hyeok Park, Seong Chan Jun
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.