2. Synergetic Effect of Graphene Oxide and Metal Organic Framework Nanocomposites as Electrocatalysts for Hydrogen Evolution Reaction

Exploiting low-cost and efficient electrocatalysts for hydrogen evolution reaction (HER) is an important route to solve the energy crisis and environmental pollution. HER process plays a vital role in many energy storage and conversion systems including water splitting, rechargeable metal–air batteries and the unitised regenerative fuel cells. The platinum-based catalysts are regarded as best electrocatalysts for the HER; nevertheless, they are very exorbitant and scarce. Therefore, it is necessary to develop efficient electrocatalysts based on carbon materials. Graphene oxide (GO), for instance, is a monolayer structure with a high contribution of sp² hybridised carbon atoms, and various oxygen-containing surface functional groups have attracted the attention of a worldwide research community in the last decades due to its various potential applications linked to the unique combination of properties, such as hardness, physical and chemical stability, high specific surface area, electron mobility and heat transfer. It can be easily manufactured by simple and scalable chemical oxidation approaches from graphite, the reduction of GO into reduced GO (rGO) is a widely used method to obtain graphene. In HER, GO can also be incorporated with metals and porous materials for synergetic effect as co-catalysts for enhancement of electrocatalytic activities. On the other hand, metal–organic frameworks (MOFs) are crystalline materials with porous network structure. They possess various compositions, large surface area, tunable pore structures and are easily functionalised. Recently, MOF‐based electrocatalysts have been rapidly developed with excellent catalytic performance, demonstrating a promising application prospect in HER. In this chapter, the background on hydrogen energy and HER structure, category and synthesis of GO and MOFs are discussed. The application of GO- and MOF-based electrocatalysts for HER is discussed in detail. Their HER parameters such as Tafel slope (b) and exchange current density (i₀) are emphatically discussed and followed by the synergetic effect of HER studies of GO/MOF composites as an alternative electrocatalyst for future hydrogen production and storage via HER mechanism.