Recent progress in transition metal nitride-based electrocatalysts for the hydrogen evolution reaction

The hydrogen evolution reaction (HER), a core process for sustainable hydrogen production, relies heavily on high-performance electrocatalysts. As noble-metal catalysts face constraints for large-scale applications, transition metal nitrides (TMNs) have emerged as promising alternatives in recent research due to their favorable activity, stability, and affordability. In order to understand the rapid advancements in this field, this review provides a brief summary of TMN-based electrocatalysts for the HER, including their structures, physicochemical properties, synthesis methods, and performance enhancement strategies. TMNs can be fabricated via gas-solid reactions, liquid phase reactions, in situ conversion by nitrogen sources, and plasma-assisted nitridation. The HER performance of TMNs can be further enhanced through multiple strategies, including phase engineering, vacancy engineering, heteroatom doping, heterostructure engineering, and morphology engineering. These strategies are effective in optimizing the adsorption intensity of HER intermediates, facilitating HER kinetics, enhancing the density of active sites, and tuning the surface chemical properties. Despite their notable potential, current research on TMN-based HER electrocatalysts is limited by several challenges, such as insufficient in-depth investigations into their catalytic mechanisms, inadequate stability under certain conditions, and difficulties in scalable and cost-effective synthesis. Future research should focus on deepening the understanding of structure-activity relationships, improving stability under different conditions, and refining fabrication methods to narrow the performance and cost gap with commercial catalysts.