Unraveling Compressive Strain and Oxygen Vacancy Effect of Iridium Oxide for Proton-Exchange Membrane Water Electrolyzers.

Iridium-based electrocatalysts are commonly regarded as the sole stable operating acidic oxygen evolution reaction (OER) catalysts in proton-exchange membrane water electrolysis (PEMWE), but the linear scaling relationship (LSR) of multiple reaction intermediates binding inhibits the enhancement of its activity. Herein, the compressive strain and oxygen vacancy effect exists in iridium dioxide (IrO)-based catalyst by a doping engineering strategy for efficient acidic OER activity. In situ synchrotron characterizations elucidate that compressive strain can enhance Ir─O covalency and reduce the Ir─Ir bond distance, and oxygen vacancy (O) as an electronic regulator causes rapid adsorption of water molecules on the Ir and adjacent Ov (Ir─O) pair site to be coupled directly into O─O intermediates.

Dynamic-Cycling Zinc Sites Promote Ruthenium Oxide for Sub-Ampere Electrochemical Water Oxidation.

Although iridium-based electrocatalysts are commonly regarded as the sole stable operating acidic oxygen evolution reaction (OER) catalysts in proton-exchange membrane water electrolysis (PEMWE) devices, their exorbitant cost and scarcity severely restrict their widespread application. Herein, we introduce a promising alternative to iridium: zinc-doped ruthenium dioxide (TE-Zn/RuO), which exhibits remarkable and enduring activity for acidic OER. characterizations elucidate that the dynamic cycling of zinc dopants serves as both electron acceptors and donors, facilitating the activation of Ru sites at low overpotentials while thwarting peroxidation at high overpotentials, thus concurrently achieving heightened activity and robust stability.

Modulating the Ruthenium-Cobalt Active Pair with Moderate Spacing for Enhanced Acidic Water Oxidation.

Ruthenium (Ru)-based catalysts have emerged as promising alternatives to Iridium (Ir) catalysts in proton exchange membrane water electrolysis cells due to their lower price and excellent oxygen evolution reaction (OER) activity. However, their stability is compromised by generation of unstable high-valence Ru sites and oxygen vacancy in a lattice oxygen-mediated (LOM) pathway. Here, a low-load Ru site on a Barium (Ba)-doped CoO (RuBaCoO) catalyst is developed with abundant Ruthenium─Cobalt (Ru─Co) pairs for enhanced acidic OER activity.