Transition metal phosphides as cardinal electrocatalytic materials for alkaline hydrogen production

Amid the growing interest in renewable energy sources and the urgent need for decarbonization in various industries, cost-effective alkaline water electrolysis has emerged as a pivotal technology enabling efficient energy conversion to produce green hydrogen fuel. With the merits of metalloid character, abundant assets, tunable composition, superior conductivity, and cost-effectiveness, transition metal phosphides (TMPs) are recognized as attractive catalytic materials for alkaline electrolyzers. Here, the recent research progress on TMPs (Ni and Co) with their standard synthetic methodology and the roles of mono to bimetallic phosphides (Ni-Co) have been comprehensively summarized. A comparative study of the catalytic hydrogen evolution reaction activity of different phosphides is also included, where the importance of energy efficiency, reaction kinetics, and surface reaction thermodynamics is emphasized. The apt tuning of the electronic and structural properties of TMPs can significantly boost their efficiency to fulfill their tremendous potential in scaling up carbon-neutral hydrogen production via alkaline water electrolysis.