Pristine metal–organic framework electrocatalysts for hydrogen production: Role of electrocatalyst properties in basic media

Abstract

The recent detrimental impacts of carbon-based fuels on the environment have necessitated the production of hydrogen as clean and renewable energy via an electrocatalytic process. However, a cathodic hydrogen evolution reaction (HER) with slow kinetics and water-splitting steps without a suitable catalyst limits its large-scale production. Herein, metal-organic frameworks (MOFs) due to the unique properties of high surface area, porosity and favourable tunability, offer significant advantages over conventional catalysts to provide greater flexibility and effective reactions in the energy sector. However, the use of MOFs as electrocatalysts faces challenges like electrode corrosion and poor electron mobility and conductivity due to the lack of an optimal fabrication approach. Additionally, there is limited information on the development of MOF materials for HER in basic medium electrolytes. Therefore, pristine MOF-based materials and applicability for HER in a basic environment were comprehensively reviewed. It was elucidated that pristine MOFs used in a basic medium are more advantageous than in an acidic medium. Furthermore, recent advancements in improving MOF electrocatalytic properties and activities were discussed. Also, the effect of pristine MOFs on rate-determining steps in HER was highlighted. In addition, the challenges and prospects of improving MOFs for HER and other field applications were examined in detail, providing a comprehensive view. It was found that solvent removal during MOF activation with metal ions and electron-donating groups on the ligand has a synergy impact on the available active sites for HER.