Revolutionizing hydrogen production and storage: Harnessing the power of MXenes for a greener and sustainable future

Abstract

Among many types of electrocatalyst materials for the hydrogen evolution reaction (HER), two-dimensional (2D) transition metal nitrides and carbides (MXenes) stand out for their distinctive characteristics. The presence of transition metals (TMs) in their structure and terminations imparts metallic conductivity, allowing for variable surface chemistry. Although early research on pure MXenes showed modest HER overpotentials, the kinetics of the hydrogen (H₂) adsorption and desorption processes still restrict their electrocatalytic effectiveness. To improve the HER kinetics of MXenes, doping has recently been investigated as a viable method for optimizing their surface and electrical characteristics. This research aims to investigate the impact of doping in MXenes by substituting functional groups, including various elements/species into the MXene matrix, and altering the interface to enhance environmentally friendly production of hydrogen. Additionally, several hydrogen storage techniques have been examined. Currently, hydrogen is employed either as a compressed gas contained in high-pressure tanks or as a liquid held in tanks. Nonetheless, the safety issues linked to traditional storage methods render the solid-state storage method an attractive option. This architecture enables reversible hydrogen storage through the potential of lightweight, high-performance solid-state materials like MXenes. Despite their considerable promise, the utilization of MXenes in hydrogen storage has not been thoroughly explored. This study provides a thorough overview of the existing applications of MXenes and MXene-based materials for hydrogen generation and storage, addressing the challenges they encounter and their possible potential prospects.