Delafossite-based electrode materials: design, synthesis and their application in electrocatalysis

Abstract

Increasingly severe energy and environmental problems demand the innovation and improvement of electrocatalytic systems, which depend on the progress of their core component, which is the catalyst. Metal oxides with layered structures have gained considerable attention in building robust electrocatalysts owing to their open spaces, highly accessible sites, and tunable electronic properties. Delafossites (A^IB^IIIO₂), comprising alternating layers of edge-linked BO₆ octahedra connected by O–A⁺–O dumbbells exhibit the typical characteristics of layered metal oxides and have an unusual heterostructure, in which individual layers attain a distinct character of their own but can interact with each other. Thus, delafossites are attractive candidates for electrochemical catalysis because of their layered characteristics, distinctive components and interlaminar interactions, unique electrochemical reconstruction behavior and featured surface-interfacial structure. Meanwhile, their flexibility allows for elaborate structural manipulation and multiphase compositing to optimize the active sites and catalytic kinetics. In this review, we summarize the design principles and synthesis methods for delafossites and introduce their applications in different electrocatalytic processes. Structure–function relationships and structural manipulation strategies for enhanced performance are also elaborated. Finally, we conclude the review with our insights and provide perspectives on the challenges and opportunities for developing advanced electrocatalytic materials based on the delafossite structure.