Heterojunction engineering in metal–organic frameworks for electrolytic water splitting: advances and perspectives

The electrocatalysis of water is a promising means of producing hydrogen energy currently and has a profoundly important impact on energy storage and regeneration. In recent years, metal-organic frameworks (MOFs) have been widely studied and used in the field of electrolysed water. Due to their large specific surface area, flexible and adjustable structure, abundant pores and uniform distribution of active sites, MOFs have shown a good electrocatalytic performance. One of the important ways to enhance the electrocatalytic kinetics is to build rich heterostructures to enhance the electrical conductivity, the number and stability of active sites and improve the adsorption/desorption of intermediate substances. In this review, we examine recent advances in the hydrogen evolution reaction and oxygen evolution reaction performance of MOFs modified through synthetic heterostructures and interface engineering. Moreover, the synthesis method, modification mechanism and influence on the activity of MOFs are described. Finally, we highlight current challenges and offer perspectives of MOFs with heterogeneous structures as electrocatalysts in practical applications. This article is part of the theme issue 'Surfaces, interfaces and heterogeneous catalysis'.