Kinetics and mechanism effects of 2D carbon supports in hydrogen spillover composites

Abstract

Extensive research has been performed using two-dimensional (2D) carbon materials as catalyst supports to achieve high-performance hydrogen storage composites through the hydrogen spillover phenomenon. However, the kinetics and mechanism effects of different support materials still need to be investigated. This study employed high-energy ball milling to fabricate Co_1−xS/C₆₀ and C_1−xS/rGO composites with stable structures and abundant hydrogen storage sites. We explored the mechanism of hydrogen adsorption behavior through electrode kinetic studies and density functional theory calculations, revealing the intrinsic relationship between material composition, structure, and hydrogen diffusion kinetics. The 2D flakes of C₆₀ and rGO support and connect C_1−xS nanoparticles, providing electron transport pathways for the composites. Theoretically, the spherical C₆₀ support with less steric hindrance showed a more vital ability to increase the hydrogen adsorption capacity, while kinetically, thin film rGO offers fast channels for hydrogen diffusion. These findings contribute to our understanding of hydrogen spillover and present opportunities to investigate the synergistic effects in 2D carbon-based composites.