High-performance bifunctional porous non-noble metal phosphide catalyst for overall water splitting

Abstract

Water electrolysis is an advanced energy conversion technology to produce hydrogen as a clean and sustainable chemical fuel, which potentially stores the abundant but intermittent renewable energy sources scalably. Since the overall water splitting is an uphill reaction in low efficiency, innovative breakthroughs are desirable to greatly improve the efficiency by rationally designing non-precious metal-based robust bifunctional catalysts for promoting both the cathodic hydrogen evolution and anodic oxygen evolution reactions. We report a hybrid catalyst constructed by iron and dinickel phosphides on nickel foams that drives both the hydrogen and oxygen evolution reactions well in base, and thus substantially expedites overall water splitting at 10 mA cm ⁻² with 1.42 V, which outperforms the integrated iridium (IV) oxide and platinum couple (1.57 V), and are among the best activities currently. Especially, it delivers 500 mA cm ⁻² at 1.72 V without decay even after the durability test for 40 h, providing great potential for large-scale applications.

Abstract

Water electrolysis provides a carbon-neutral means to generate hydrogen fuel from water, but the process typically requires expensive, rare metal catalysts. Here, the authors prepare hydrogen- and oxygen-evolving electrocatalysts from earth-abundant elements that outperform noble-metal counterparts.