MXenes for hydrogen energy systems: Advances in production, storage, fuel cells, and safety applications

MXenes, the new family of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, have shown great potential as materials for hydrogen energy systems. Their conductivity, surface tunability, large surface area, and structural stability render them ideal for hydrogen production, storage, fuel cells, and safety. This article discusses the contribution of MXenes towards the development of hydrogen technologies in surmounting efficiency, scalability, and cost limitations. MXenes electrocatalysts for hydrogen evolution enhance the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with enhanced catalytic activity and stability compared to conventional materials. The use of MXenes in proton exchange membrane fuel cells (PEMFCs) is efficient in increasing electrode stability while reducing reliance on platinum catalysts. Beyond PEMFCs, the potential of MXenes is also being explored in other fuel cell platforms such as solid oxide fuel cells (SOFCs), alkaline fuel cells (AFCs), and microbial fuel cells (MFCs), highlighting their broader versatility in hydrogen conversion technologies. MXenes possess better hydrogen storage capabilities via physisorption and chemisorption, enabling reversible hydrogen adsorption with high capacity. Besides, MXenes hybrids with metal hydrides and porous materials improve storage kinetics and temperatures and address major challenges in hydrogen storage. Besides production and storage, MXenes-based sensors for detecting hydrogen provide realtime leak detection with high selectivity and sensitivity, enhancing safety in hydrogen infrastructure. Despite their many advantages, stability under operational conditions, scalability of synthesis, and production costs are present obstacles to commercialization. Future research should focus on optimizing their electrochemical performance, functionalization pathways, and mass production synthesis. MXenes hold great promises to revolutionize hydrogen energy systems and facilitate the transition to a sustainable, low-carbon energy future by improving hydrogen efficiency, safety, and affordability.