Emerging Materials for Energy and Sensing Applications

Abstract

Electrochemical water splitting, a pivotal technology for clean hydrogen production, hinges on the development of efficient catalysts to expedite the challenging oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In recent years, defect-rich catalysts have emerged as a compelling avenue in the pursuit of enhanced catalytic performance. This book chapter delves into the pivotal role played by defect-rich materials in advancing the field of electrochemical water splitting. We begin by elucidating the fundamental concepts of defects in catalyst materials, encompassing oxygen vacancies, metal cation vacancies, and edge defects. We explore how these defects can facilitate charge transfer kinetics, modulate surface reactivity, and influence the overall electrocatalytic activity of materials. The chapter showcases a diverse array of defect-rich catalysts, including transition metal oxides, layered double hydroxides, and carbon-based materials, highlighting their promising applications in both the OER and HER. Furthermore, we delve into the mechanistic insights underpinning the catalytic enhancement enabled by defects, shedding light on the intricate interplay between defect types, defect density, and catalytic activity. A discussion of the synthesis strategies to deliberately engineer defects in catalyst materials is also presented. Finally, we offer a glimpse into the prospects of defect-rich catalysts and their potential to drive innovation in sustainable hydrogen production. This chapter serves as a comprehensive guide for researchers and practitioners seeking to harness the power of defects in the realm of electrochemical water splitting. © 2025 Kuldeep Singh Gour and Vidya Nand Singh.