Metastable-phase 2D noble-metal oxides: syntheses and advanced catalysts

Metastable-phase 2D noble-metal oxides, combining the advantages of noble-metal oxides, 2D materials, and metastable-phase materials are considered some of the most promising new catalysts for catalytic reactions. However, the thermodynamic instability of metastable-phase materials can lead to their transition to a stable phase resulting in the decay of catalytic activity, which is far from satisfactory in practical applications. In this review, research progress on metastable-phase 2D noble-metal oxides towards electrocatalysis is reported, including IrO2, RuO2, RhO2 and PtO2, with emphasis on the advantages of metastable-phase 2D noble-metal oxides, detailed synthesis methods and catalyst-design strategies. Finally, the future prospects and challenges of metastable-phase 2D noble-metal oxide catalysts are provided.