Application of MXenes for air purification, gas separation and storage: A review

MXenes are a new type of two-dimensional (2D) inorganic compound which offer high surface area, superlative chemical stability, thermal conductivity, hydrophilicity and environmental compatibility in comparison to traditional 2D ceramics. Consequently, MXenes have been employed for a range of environmental, chemical and medical applications like air purification and gas storage, often outperforming conventional materials in each field. MXene-composites can adsorb toxic gases, particulate matter and exhibit promising anti-bacterial properties when used for air purification applications at room temperature and pressure. This approach allows for a significant decrease in the energy demand, offering a solution for low-energy gas storage and air purification. This article presents a state-of-the-art review on gas storage, particularly for CH4, CO2 and H2 and air purification applications of MXenes and MXene-composites. An investigation into gas uptake capacity is presented for CO2, H2 and CH4, as well as the mechanisms involved in contaminant uptake, such as chemisorption, electrostatic interactions and van der Waals interactions are also discussed. The application of MXenes for carbon dioxide separation during pre-combustion, post-combustion and adsorption during direct air capture is also examined. The effects of MXene synthesis procedures and operational protocols on the adsorption efficacy and long-term usage are also highlighted.