How Does Nanoconfinement Affect the Hydrogen Storage Capacity in MXene Slit Pores?

Document Type

Article

Publication Date

5-7-2026

Department

Department of Physics

Abstract

In this paper, we have investigated the effect of nanoconfinement with the slit-pore width of multilayer Tin+1CnTx (n = 1, 2) MXenes as a tunable parameter on the hydrogen storage capacity using a revised thermodynamic model developed for slit-pore materials across a wide range of pressure and temperature. We highlight that the surface termination plays an important role in dictating the surface adsorption energy of hydrogen molecules, which effectively determines the optimum slit-pore width to store hydrogen and, subsequently, the optimum hydrogen storage capacity. Our calculations showed that an upper bound of slit-pore width ranging from 8 to 40 Å, for uniform and ternary O-/OH-/F-mixed terminated Tin+1CnTx (n = 1, 2), is suitable for enhancing the hydrogen storage capacity while maintaining a substantial nanoconfinement effect and thermodynamic stability. Our study suggests that a 40% increase in the surface adsorption energy could result in a 4-fold increase in the predicted hydrogen storage capacity. The calculated upper bound of the hydrogen gravimetric storage capacity of the multilayer Ti3C2Tx can achieve up to ∼6.5 wt % H2 at 77 K and 5 MPa and an even higher capacity of ∼9.5 wt % H2 at 77 K and 5 MPa for multilayer Ti2CTx, demonstrating their suitability for hydrogen storage applications. By determining the range of optimum slit-pore width that balances the gravimetric and volumetric storage capacity for hydrogen, the optimum slit-pore width of multilayer Tin+1CnTx (n = 1, 2) is about 13−18 Å. Based on this optimum slit-pore width, the predicted optimum hydrogen gravimetric and volumetric storage capacity of the multilayer Ti3C2Tx slit pore is found to be 3.10 wt % and 47.96 g/L at 77 K and 5 MPa and is found to be comparable to metal organic frameworks (MOFs). Meanwhile, compared with the monolayer, the multilayer with slit pores demonstrated a significant improvement in terms of gravimetric storage capacity and desorption of hydrogen due to the nanoconfinement effect. This slit-pore nanoconfinement helps in stabilizing the hydrogen molecules’ desorption with a steady and slower rate of desorption and is beneficial for hydrogen storage applications.

Publication Title

ACS Applied Energy Materials

Link to Full Text

Share

COinS