The efficiency of HER largely depends on the catalyst used. Platinum (Pt) is considered the benchmark catalyst due to its high activity and stability. However, its high cost and scarcity limit its widespread use. Therefore, research has focused on developing cost-effective alternatives such as transition metal dichalcogenides (e.g., MoS2), metal phosphides (e.g., Ni2P), and metal-nitrogen-carbon complexes (e.g., Fe-N-C).
