Advancing strategies on green H2 production via water electrocatalysis: bridging the benchtop research with industrial scale-up

Water splitting provides clean hydrogen via different technologies such as alkaline water electrolysis, proton exchange membrane electrolyzers, solid oxide electrolysis cells, and photoelectrolysis, each with advantages and challenges. The focus on alkaline water electrolysis highlights its maturity compared to emerging methods. Non-noble metal catalysts offer increased stability, low cost and operational lifespan. Challenges such as low current density, gas crossover, corrosive electrolytes, and limited efficiency are still to be addressed. These advanced electrocatalysts are summarized for alkaline oxygen and hydrogen evolution reactions. Meanwhile, different factors including product gas bubble management, operation conditions, separator and electrolyte affecting the performance were concluded and discussed. For the promising approach, seawater splitting is still far from large-scale application. Salinity, pH fluctuations, and complex composition are significant obstacles. The review underscores the need for improvements in electrocatalysts to enhance the efficiency, stability, and practicality of water splitting for hydrogen production, ultimately contributing to the growth of the clean hydrogen market and supporting the transition to sustainable energy systems.