Recent Progress in Zn‐Air Battery‐Driven Water Electrolysis for Self‐Powered Hydrogen Production: A Review from a Materials Perspective

ABSTRACT In view of increasing demands for sustainable and CO 2 ‐neutral energy conversion technology, there is an urgent need to explore energy storage and green hydrogen generation systems, wherein both operations are coupled together. One of the recent advances in this area involves using the energy generated from Zn–air battery‐operated water electrolysis to produce hydrogen without any requirement for external power. Efficiency in this approach largely relies upon the availability of electrocatalytic systems for HER, OER, and ORR reactions. This review provides a concise, material‐oriented overview of the developments made in recent times regarding advanced electrocatalytic materials used for these reactions, including transition metal‐based catalysts, noble metal‐based catalysts, single‐atom catalysts, MOF‐derived materials, and metal‐free catalysts. The importance of studying the relationship between structure and activity, synergism, and ways to improve the efficiency of catalysis for multiple reactions are emphasized. An overview of the basic principles involved in HER, OER, and ORR are also given to contextualize the function of catalysts into perspective. While great progress has been made in achieving higher activity, stability, and multifunctionality, there are still problems concerning cost, durability, and scalability remains, which are discussed in this review to highlight future research directions and facilitate practical applications.