Construction of Built-in Electric Field With NiFe-Based Heterointerface for Efficient Oxygen Evolution Reaction in...

Alkaline anion exchange membrane water electrolyzer (AEMWE) is a promising technology for green hydrogen production. However, AEMWE often operates under elevated temperatures, which accelerates the corrosive effects of alkaline electrolytes toward the electrolyzers, compromising its performance over time. In this work, built-in electric field (BEF) induced by NiFe-based heterointerface was constructed to enhance both OER and AEMWE performance even operating under near room temperatures, which was achieved by integrating FeP₄ onto Ni₃S₂ surface. Benefiting from the BEF effect, it achieved 10 and 100 mA cm^-2 OER current densities at 226 and 258 mV, respectively. More importantly, when it was employed as anode in AEMWE, it delivered 1 A cm^-2 current density at a comparatively small cell voltage of 1.94/1.91/1.84 V at near room temperatures of 30/40/50°C, competitive to those of earlier reported NiFe-based electrocatalyst operating at higher temperatures (60-80°C). Density functional theory simulation reveals the induced BEF facilitates asymmetrical charge distribution, thus optimized the nucleophilic attack process with regards to oxygen intermediates, thereby lowering their adsorption energy during reaction. This work highlights the potential of a BEF-based strategy for enhancing OER in AEMWE operating at near room temperatures.