MXene: A New Family of Promising Hydrogen Storage Medium

TLDR

Reversible hydrogen storage under ambient conditions remains a major challenge, yet the strong Ti–C covalent bonds in 2D Ti₂C prevent transition‑metal clustering. The study systematically investigates the hydrogen storage properties of the 2D Ti₂C MXene phase using density‑functional calculations. Density‑functional calculations were performed to evaluate hydrogen adsorption on Ti₂C. The calculations and ab initio molecular dynamics show Ti₂C can reversibly store 3.4 wt % hydrogen via Kubas‑type binding at 0.272 eV, and similar performance is predicted for other MXenes, indicating the family is a promising ambient‑condition storage material.

Abstract

Searching for reversible hydrogen storage materials operated under ambient conditions is a big challenge for material scientists and chemists. In this work, using density functional calculations, we systematically investigated the hydrogen storage properties of the two-dimensional (2D) Ti2C phase, which is a representative of the recently synthesized MXene materials ( ACS Nano 2012 , 6 , 1322 ). As a constituent element of 2D Ti2C phase, the Ti atoms are fastened tightly by the strong Ti-C covalent bonds, and thus the long-standing clustering problem of transition metal does not exist. Combining with the calculated binding energy of 0.272 eV, ab initio molecular dynamic simulations confirmed the hydrogen molecules (3.4 wt % hydrogen storage capacity) bound by Kubas-type interaction can be adsorbed and released reversibly under ambient conditions. Meanwhile, the hydrogen storage properties of the other two MXene phases (Sc2C and V2C) were also evaluated, and the results were similar to those of Ti2C. Therefore, the MXene family including more than 20 members was expected to be a good candidate for reversible hydrogen storage materials under ambient conditions.