Metal-organic framework/graphene-based nanocatalysts for hydrogen evolution reaction: A comprehensive review

De novo engineering of reticular metal-organic frameworks atop graphene-based materials is a fascinating idea for developing advanced clean energy technologies. By virtue of their multifunctional lattice and flat yet flexible sheet structure, graphene and its analogs act as metal-organic framework structuring agents to endow them with intriguing morphological, textural, topographical, spatial, interfacial, chemical, electrical, and mechanical characteristics. The synergistic benefits of the metal-organic framework/graphene-based hybrids became viable alternatives for expensive noble metal-based catalysts. Despite advancements, none of the previous reviews primarily emphasized metal-organic framework/graphene-based nanocatalysts for hydrogen evolution reactions. The present review aims to bridge this information lapse by summarizing the research progress of such hybrid nanocatalysts for hydrogen production. It manifests the superiority of metal-organic framework catalysts for hydrogen generation compared to conventional materials and elucidates the rationale and broadened hydrogen evolution reaction scope of hybridizing pure metal-organic frameworks with graphene and derivatives. Furthermore, it overviews preparation techniques, examines characteristic features, and comprehensively evaluates hydrogen evolution reaction performance of so far documented metal-organic framework/ graphene-based hybrid photocatalysts and electrocatalysts. Finally, it discloses the current status, existing challenges, and potential future advances of these metal-organic framework/graphene-based hybrids.