Electrochemical hydrogen generation technology: Challenges in electrodes materials for a sustainable energy

Abstract Foresee advanced and innovative strategies is a key approach and constitutes a cornerstone for accessing clean, affordable, and reliable energy to satisfy the world's increasing prosperity and economic growth. To this end, hydrogen energy technologies parade as promising sustainable solutions to the looming energy crisis at either the small or large industrial scale, which will enable to reduce significantly our dependence on conventional energy sources based on fossil fuels without increasing atmospheric CO 2 levels. Water electrolysis with renewable energy is one of the best solutions to produce hydrogen without CO x (CO and CO 2 ) emissions. However, the practical realization of this elegant opportunity of paramount importance is facing several challenges, among which are: (i) the efficient design of cathode and anode catalytic materials exhibiting improved intrinsic and durable activity; (ii) the scale‐up of the system for the large‐scale hydrogen production through the electrochemical water splitting. This review puts these opportunities and challenges into a broad context, discusses the recent research and technological advances, and finally provides several pathways and guidelines that could inspire the development of groundbreaking electrochemical devices for hydrogen production. It also points out the materials design and preparation for the efficient electrochemical production of the molecular hydrogen in acidic and alkaline environments, from a simple electrolytic solution to the water splitting reaction, which is also considered in the process. Furthermore, the main technology keys for designing a reliable electrochemical system will be noticed.