Exploring Carbon Nanotubes for Enhanced Hydrogen Storage: A Review on Synthesis, Mechanisms, and Evaluation

Abstract

In pursuing a carbon–neutral world, hydrogen’s environmentally friendly attributes and high energy density make it a promising fossil fuel alternative. The main challenge in using hydrogen as a clean energy source is the need for dependable storage technology. Material-based solid-state systems are favored for their reliability over conventional storage methods and for meeting the DoE, USA targets. Carbon nanotube-based materials stand out among material-based hydrogen storage systems due to their unique advantages over others. High surface area, mesoporous structure, tunable features, honeycomb structure, chemical stability, low mass density, hydrogen molecule dissociation and an easy synthesis process are only a few of its distinctive qualities. Many material-based hydrogen storage systems rely on chemisorption, lacking reversibility and necessitating energy for hydrogen release. In contrast, CNT-based materials predominantly employ physisorption, merely adsorbing hydrogen without chemical bonding. This approach allows for more efficient hydrogen release, ensuring superior stability and reversibility compared to other material-based systems. This review paper assesses the hydrogen storage capabilities, different properties and rapid adsorption/desorption kinetics of carbon nanotube-based materials at lower temperatures. It discusses preparation methods and influencing mechanisms and explores both pristine and modified CNTs’ potential for hydrogen storage alongside safety considerations and future prospects.