Heteroatom-Doped Carbon Allotropes in Water-Splitting Application

Water-splitting technology is crucial for generating green hydrogen energy, a sustainable and clean fuel source that can significantly decrease reliance on fossil fuels and reduce greenhouse gas emissions, thereby helping to mitigate the global energy crisis. Renewable energy sources are expected to significantly replace fossil fuels, contributing to lowering greenhouse gas releases and helping to mitigate the energy crisis. The water-splitting process for generating green hydrogen energy is acknowledged as a promising approach toward achieving carbon neutrality. In this context, the attributes and features of electrocatalysts have a crucial part in shaping the reaction activity and selectivity of both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) processes involved in the water-splitting process. In addition to traditional noble-metal-based catalysts, carbon-based materials like carbon nanotubes (CNTs), graphene, and porous carbons have proven effective for catalyzing these reactions. A highly effective strategy to enhance their electrical, physical, and chemical characteristics involves doping them with heteroatoms like nitrogen (N), sulfur (S), phosphorus (P), boron (B), and transition metals. These materials, renowned for their exceptional characteristics, have been extensively researched in both the academic and industrial sectors for diverse applications, like energy conversion and storage technologies. This chapter comprehensively reviews notable advancements in the progress of heteroatom-doped carbon allotropes materials and their utilization in overall water splitting, highlighting different synthesis methods and strategies like templating strategy, hydrothermal/solvothermal synthesis, chemical vapour deposition (CVD), and high-temperature annealing aimed at achieving heteroatom-doped carbon allotrope materials with diverse types and quantities of dopants (both metallic and non-metallic), as well as multi-atoms. Additionally, the discussion underlines the structural and morphological characteristics that elucidate the structure-property relationship and improvements in the physicochemical features of heteroatom-doped carbon allotropes. It explores how heteroatom doping enhances different properties, such as conductivity, and optimizes surface adsorption for various reaction intermediates, as evidenced by density functional theory (DFT) calculations. Finally, the chapter explores recent promising studies of heteroatom-doped carbon allotropes with excellent catalytic performance and reveals their future prospects for overall water splitting.