Theoretical investigations of hydrogen gas sensing and storage capacity of graphene-based materials: A review

Abstract

Excessive usage of fossil fuel energy in recent years has prompted the development of an alternative fuel with potential to meet energy requirements. Hydrogen has emerged as one of those fuels which can be produced from renewable sources and its combustion produces only heat and water. It is a high-quality energy carrier and can be used in transportation and energy storage devices. Many studies have been performed to examine the appropriate hydrogen sensing and storage materials. Graphene-based materials can be exploited for hydrogen adsorption and storage owing to their wonderful properties i.e. a very large surface area, high conductivity, high mobility of charge carriers, great mechanical strength, etc. Pure graphene does not comply with the criteria for hydrogen storage as set out in the Department of Energy, United States of America. As a result, efforts are being made in this direction to modify graphene and meet the specific requirements. The hydrogen storage on graphene-based solid-state sensors may occur through either physisorption or chemisorption. Density Functional theory helps to estimate the capacity of defected and doped graphene materials for hydrogen adsorption before experimental investigation. Multilayer graphene influences the performance of gas sensing by intercalating metal and non-metal atoms via atomic bonding. It estimates the adsorption energy, charge density, Density of states, band gap values, and gravimetric density to determine the sensing ability of the material. The present review is focused on the several DFT studies made for investigating the hydrogen adsorption and storage properties in graphene-based materials.