Non-precious hydrogen evolution reaction catalysts: Stepping forward to practical polymer electrolyte membrane-based zero-gap water electrolyzers

Water electrolysis (WE) technologies powered by renewable energy sources are promising methods for sustainable hydrogen production as they do not contribute toward resource depletion and pollutant emissions. However, to benefit from these technologies, their high capital costs must be addressed. The development of nonprecious catalysts for hydrogen evolution reaction, which is a hydrogen-generating electrochemical reaction in WE, addresses this issue. However, most non-precious hydrogen evolution catalysts have only been evaluated at the half-cell level, and their practical applicability to WE has not been confirmed. Herein, we review nonprecious hydrogen evolution reaction catalysts implemented in anion and proton exchange membrane WE, which are efficient WE methods owing to their low ohmic losses and ease of product gas separation. We also discuss the importance of implementing non-precious catalysts in water electrolyzers and standardizing an evaluation method.

Automated summary

Water electrolysis technologies powered by renewable energy sources are promising for sustainable hydrogen production. The development of nonprecious catalysts is crucial to address high capital costs. However, the practical applicability of these catalysts in water electrolyzers is yet to be confirmed as most evaluations have been conducted at the half-cell level.