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<p>Efficient hydrogen storage materials are essential for sustainable hydrogen based energy economy. The 2D α-GeTe monolayer is a promising candidate owing to its high carrier mobility, moderate bandgap, and air stability, but its hydrogen adsorption behavior has not yet been explored. In this work, density functional theory (DFT) calculations combined with kinetic Monte Carlo (kMC) simulation are employed to investigate the adsorption of H<sub>2</sub> molecules and the time evolution of surface coverage on the α-GeTe monolayer. It is found that the maximum adsorption energy of the H<sub>2</sub> molecule at the Ge site is ̶ 45.8 meV at an equilibrium adsorption height of 2.6 Å, indicating weak physisorption. Bader charge analysis reveals that a very small charge transfer of about 0.007e from GeTe monolayer to H<sub>2</sub> molecule. In addition, electron localization function (ELF), band structure and density of states (DOS), have been examined to understand the adsorption mechanism. The optimized GeTe monolayer exhibits an indirect band gap of 1.73&#xa0;eV using the GGA-PBE exchange-correlation functional. The electronic band structure of GeTe monolayer remains unchanged upon adsorption of H<sub>2</sub> molecule at the Ge site, confirming the weak interaction between H<sub>2</sub> molecule and the substrate. In the case of multiple adsorptions, the GeTe monolayer unit cell can adsorb two H<sub>2</sub> molecules, corresponding to a gravimetric storage capacity of approximately 2 wt %. Furthermore, the kMC simulation has been employed to describe the rate of adsorption and desorption along with surface coverage of H<sub>2</sub> molecule on the GeTe monolayer under varying pressure and temperature. The kMC simulation results reveal that a considerable surface coverage (~ 60 %) is achieved at high pressure (5&#xa0;atm) and temperatures below room temperature.</p>

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Possibility of storage of molecular hydrogen in GeTe monolayer

  • 期刊论文

  • 发表日期：

    2026年7月16日

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  • Jabed Aktar Khan,
  • Sulagna Ghosh,
  • Palash Nath,
  • Dirtha Sanyal

摘要

Efficient hydrogen storage materials are essential for sustainable hydrogen based energy economy. The 2D α-GeTe monolayer is a promising candidate owing to its high carrier mobility, moderate bandgap, and air stability, but its hydrogen adsorption behavior has not yet been explored. In this work, density functional theory (DFT) calculations combined with kinetic Monte Carlo (kMC) simulation are employed to investigate the adsorption of H2 molecules and the time evolution of surface coverage on the α-GeTe monolayer. It is found that the maximum adsorption energy of the H2 molecule at the Ge site is ̶ 45.8 meV at an equilibrium adsorption height of 2.6 Å, indicating weak physisorption. Bader charge analysis reveals that a very small charge transfer of about 0.007e from GeTe monolayer to H2 molecule. In addition, electron localization function (ELF), band structure and density of states (DOS), have been examined to understand the adsorption mechanism. The optimized GeTe monolayer exhibits an indirect band gap of 1.73 eV using the GGA-PBE exchange-correlation functional. The electronic band structure of GeTe monolayer remains unchanged upon adsorption of H2 molecule at the Ge site, confirming the weak interaction between H2 molecule and the substrate. In the case of multiple adsorptions, the GeTe monolayer unit cell can adsorb two H2 molecules, corresponding to a gravimetric storage capacity of approximately 2 wt %. Furthermore, the kMC simulation has been employed to describe the rate of adsorption and desorption along with surface coverage of H2 molecule on the GeTe monolayer under varying pressure and temperature. The kMC simulation results reveal that a considerable surface coverage (~ 60 %) is achieved at high pressure (5 atm) and temperatures below room temperature.