Synthesis, properties and applications of carbon nanomaterials functionalized with anionic groups

Abstract

Anion-modified carbon nanomaterials (CNMs) represent a diverse class of functional nanomaterials that have attracted considerable interest due to their tunable properties and diverse applications. These materials are obtained by covalent attachment of negatively charged groups such as carboxylate, sulfonate/sulfate, and phosphonate to various CNMs, including carbon nanotubes, graphene, and carbon dots. The synthesis, characterization, and performance of these materials are affected by the type and quantity of anionic groups as well as the nature and morphology of the CNMs. This review provides a comprehensive overview of recent advances in anionic CNMs, including preparation methods, structural and surface analysis techniques, and applications in catalysis, ion exchange, membrane fabrication, electrochemical energy storage, and chemical sensing. Additionally, challenges and perspectives for future research in this emerging field will be discussed. While there are reviews on specific aspects of anionic CNMs, there is a lack of a comprehensive review on various negatively charged CNMs. The present review aims to address this gap by providing an overview of covalent modifications using carboxylate, sulfonate/sulfate, and phosphonate groups. The focus is on low molecular weight anionic fragments.