First-principles study of hydrogen storage application of Ti3C2Tx monolayer MXene

Abstract

MXene, with its high aspect ratio and adjustable surface properties, has garnered significant attention in the realm of hydrogen storage research. For the first time, considering a ternary/quaternary mixed terminated MXene surface, the authors have investigated comprehensively the hydrogen storage potential of two-dimensional (2D) titanium carbide Ti3C2Tx monolayer MXene using density functional theory (DFT). By considering mixed terminated surfaces, this study indicated the locally induced dipole due to the mixed termination is beneficial in facilitating hydrogen adsorption with stronger average adsorption energies than that of the uniform F-/O-/OH-/H-terminated surfaces. The authors estimated a compelling average H2 surface adsorption energy on the ternary mixed termination and total surface storage capacity to be −0.14 eV/H2 and ∼2 wt% H2, which is comparable to that of the metal-organic frameworks (MOFs). This study also reveals the importance of the local surface chemistry effects on hydrogen adsorption.