New opportunities for emerging two-dimensional metastable-phase noble metal oxides in acidic electrocatalytic water splitting

Metastable-phase materials possess unique structures, high Gibbs free energy, abundant active sites, and adjustable physicochemical properties, making them ideal candidates for optimizing electrocatalysis. As metal oxides are stable under harsh reaction conditions, by controlling the morphology, defects and phase structure of the material, the surface electronic structure of metal oxides can be adjusted to a great extent, and their catalytic performance can be optimized. As a novel addition to the 2D material family, metastable-phase noble metal oxides exhibit significant promise for catalytic reactions. Here, the latest research progress and advantages of 2D metastable-phase noble metal oxides are reviewed, and their application in acidic electrocatalytic water splitting is presented. Finally, the challenges associated with 2D metastable-phase noble metal oxides and future perspectives are discussed.