Multi-fold catalytic activities of Ni nanoparticles supported on TiN for improving the hydrogen storage of NaAlH4

Abstract

The high desorption temperature and sluggish kinetics of NaAlH₄ limit its applications in hydrogen storage. To address these issues, a Ni nanoparticles-loaded TiN composite catalyst with excellent thermodynamic stability and catalytic activity was constructed. The addition of 5 wt% Ni₁₀@TiN reduced the initial dehydrogenation temperature of NaAlH₄ to 81 °C, and a total amount of 5.4 wt% H₂ could be released within 20 min at 170 °C. The activation energies for the two-step dehydrogenations were significantly reduced to 66.3 kJ/mol and 81.4kJ/mol, respectively, which were 43 % and 36 % lower than that of pure NaAlH₄. Experimental results and theoretical calculations suggested that these remarkable improvements were originated from the grain refinement of NaAlH₄ and multi-fold catalytic activities of Ni₁₀@TiN catalyst like providing catalytic active sites, facilitating the breaking of Al-H and H-H bonds, and increasing hydrogen diffusion channels. These findings may offer new ideas for designing high-efficiency catalysts for solid-state hydrogen storage materials.