Engineering RuO2 by Configurational Entropy for Durable Proton Exchange Membrane Water Electrolysis

Abstract

Non-iridium acid-stabilized electrocatalysts for the oxygen evolution reaction (OER) are crucial to reducing the cost of proton exchange membrane water electrolyzers (PEMWEs) for large-scale applications. Here, we report a strategy to modulate the configurational entropy of RuO2 by doping boron (B) atoms, leading to the preparation of a RuO2 catalyst with long-range disorder (LD-B/RuO2). The structure of long-range disorder endowed LD-B/RuO2 with a low overpotential of 175 mV for OER and an ultra-long stability, which can maintain the OER process for about 1.6 months (more than 1200 h) at 10 mA cm-2 current density in 0.5 M H2SO4 with almost invariable performance. More importantly, a PEM electrolyzer using LD-B/RuO2 as the anode demonstrated excellent performance, reaching 1000 mA cm−2 at 1.63 V with durability exceeding 300 h at a current density of 250 mA cm−2. The introduction of B atoms induced the formation of a long-range disordered high-configuration entropy structure and symmetry-breaking B-Ru-O motifs, which enabled the catalyst structure to have a certain degree of resilience and self-healing while simultaneously inducing the redistribution of electrons on the active center Ru, which jointly promoted and guaranteed the activity and long-term stability of LD-B/RuO2.

Keywords: Non-iridium, long-range disordered, configurational entropy, acidic OER, PEM water electrolysis