Recent advances in emerging single atom confined two-dimensional materials for water splitting applications

Single metal atoms confined in two dimensional (2D) materials have gained substantial attention as potential heterogeneous catalysts for various electrochemical applications. Single-atom catalysts (SACs) can be defined as a class of isolated metal atoms that are either atomically dispersed or coordinated with neighboring surface atoms of an appropriate support. Unlike nanoparticles or bulk materials, SACs offer unique characteristics which turn them as superior candidate for various catalytic applications. This review aims to summarize recent advances in various synthetic approaches and characterization techniques used to design different SACs. After this overview, we focus our discussion on single atom-2D support interactions, followed by recent progress in single atom incorporated 2D catalysts for water splitting applications, which includes both electrocatalytic and photocatalytic hydrogen production. Finally, we summarize the current challenges and the future outlook exists for the rational design of single atom based new catalyst with high catalytic activity, better stability and selectivity for various sustainable energy conversion applications.