Enhanced hydrogen storage performance of g-C₃N₄/CoMn₂O₄ nanocomposites

This work investigates the graphitic carbon nitride (g-C₃N₄) and g-C₃N₄/CoMn₂O₄ nanocomposites as potential materials for solid-state hydrogen storage applications. Initially, the CoMn₂O₄ was prepared by facile hydrothermal technique and g-C₃N₄ was synthesized via a one-step calcination process. The g-C₃N₄/CoMn₂O₄ composites were prepared through ultrasonic-assisted wet impregnation method and their physical and chemical properties were investigated systematically. Thermogravimetric analysis confirmed that the samples were thermally stable up to 500 °C. Hydrogenation studies were carried out at 150 °C for 30 min under 5 and 10 bar pressures. In the dehydrogenation process, the g-C₃N₄ desorbed 1.58 wt% and g-C₃N₄/CoMn₂O₄ 650 nanocomposite desorbed 2.25 wt% of hydrogen from RT to 500 °C. The g-C₃N₄/CoMn₂O₄ 650 shows lower desorption activation energy and binding energy (E_d = 15.81 kJ mol⁻¹ & E_b = 0.252 eV) compared to g-C₃N₄ (E_d = 16.54 kJ mol⁻¹ & E_b = 0.260 eV) respectively.