Earth-abundant nanomaterials for electrolytic hydrogen production: Advances, mechanistic insights, and industrial prospects

The urgency to secure our energy future has intensified due to a growing global population, increasing energy consumption, and the undeniable effects of climate change. Significant efforts are underway to develop clean, sustainable, and highly efficient energy production strategies to meet the demands of modern society. Electrocatalysis for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is one of the many cutting-edge technologies, and several novel electrocatalysts have been established to increase the efficiency of green hydrogen (H2) production systems. Earth-abundant transition metal nanomaterials hold immense promise as catalysts for high-performance electrolytic hydrogen production, making them crucial for advancing next-generation hydrogen-based energy technologies. This review aims to critically summarize the recent developments in highly active and durable electrocatalysts, including both conventional and emerging synthesis strategies such as hydrothermal, pyrolysis, electrodeposition, and laser processing. This review begins with foundational concepts in electrode kinetics and measurement standards for assessing OER/HER electrocatalysts. The present review highlights the catalytic overall water splitting activity of the nanomaterials, metal oxides, metal chalcogenides, metal pnictides, metal-organic frameworks (MOFs), organometallics, MXenes, and single-atom catalysts (SACs) is critically highlighted. In situ approaches, critical assessment, and artificial intelligence (AI)/machine learning (ML) strategies to improve the electrocatalytic activity during OER/HER processes are covered in this review, facilitating the development of ideal electrocatalysts for extended catalyst lifespan. Finally, the potential approaches, challenges, and future perspectives for enhancing OER/HER performance considering upcoming advancements are also described.