2D Ruthenium–Chromium Oxide with Rich Grain Boundaries Boosts Acidic Oxygen Evolution Reaction Kinetics

Abstract

Ruthenium oxide is currently considered as the promising alternative to Ir‐based catalysts employed for proton exchange membrane water electrolyzers but still faces the bottlenecks of limited durability and slow kinetics. Herein, a 2D amorphous/crystalline heterophase ac‐Cr0.53Ru0.47O2‐δ substitutional solid solution with pervasive grain boundaries (GBs) is developed to accelerate the kinetics of acidic oxygen evolution reaction (OER) and extend the long‐term stability simultaneously. The ac‐Cr0.53Ru0.47O2‐δ shows a super stability with a slow degradation rate and a remarkable mass activity of 455 A gRu−1 at 1.6 V vs RHE, which is ≈3.6‐ and 5.9‐fold higher than those of synthesized RuO2 and commercial RuO2, respectively. The strong interaction of Cr–O–Ru local units in synergy with the specific 2D structural characteristics of ac‐Cr0.53Ru0.47O2‐δ dominates its enhanced stability. Meanwhile, high‐density GBs and the shortened Ru‐O bonds tailored by amorphous/crystalline structure and Cr–O–Ru interaction regulate the adsorption and desorption rates of oxygen intermediates, thus accelerating the overall acidic OER kinetics.

A Review on Highly Efficient Ru-Based Electrocatalysts for Acidic Oxygen Evolution Reaction

“…Two-dimensional (2D) nanostructures, especially ultrathin nanosheets, have the advantage of exposing almost all atoms as active sites, which promotes fast interfacial charge transfer. − Cui et al used the solvothermal method to synthesize fcc-Ru 3 Ir with a thickness of about 4 nm measured by the atomic force microscopy (AFM) measurement (Figure e), which has low surface energy and can effectively inhibit soluble metal oxide formation . Huang’s group synthesized RuCu NSs with a snowflake-like morphology; a high-angle annular dark-field scanning TEM (HAADF-STEM) image revealed the abundantly accessible channels on RuCu NSs, which led to a greater acidic OER activity of RuCu NSs than RuCu NPs and commercial catalysts (Figure f,g) .…”