Carbon nitride nanotube-based materials for energy and environmental applications: a review of recent progresses

Abstract

Among the diverse graphitic carbon nitride (CN) nanostructures, CN nanotubes (CNNTs) are currently attracting increasing interest due to the appealing properties of CN and the geometric advantages of one-dimensional (1D) nanotubes. CN is a metal-free photocatalyst and has the advantages of exceptional electronic band structure, rich nitrogen content, and high physicochemical stability. Nanotubes have a unique 1D hollow nanostructure, and they provide large surface area, high aspect ratio, electron mobility along the axial direction, and quantum confinement effects. Therefore, CNNTs and CNNT-based materials have been extensively explored in many energy- and environment-related fields. In this review, the functional merits of CNNTs and recent progress in the precursor-based synthesis of CNNTs are discussed. Besides, the corresponding applications of CNNT-based nanomaterials are summarized, such as photocatalytic H₂ production, pollutant degradation, and CO₂ reduction. Moreover, the modification strategies of CNNTs using elemental doping, texture tailoring, and heterojunction engineering are comprehensively discussed. Finally, the future challenges and opportunities of CNNT-based nanostructures are proposed. With the rapid development of materials science and technology, more efforts need to be devoted toward promoting the advanced functionalities and promising applications of CNNT-based materials.