Pd-modified LaNi5 nanoparticles for efficient hydrogen storage in a carbazole type liquid organic hydrogen carrier

In this work, we report the synthesis and catalytical property of a palladium catalyst loaded on a hydrogen storage support-Pd/LaNi 5 in reversible hydrogen storage of N-ethylcarbazole (NEC). We prepare LaNi 5 nanoparticles by the molten salt reduction method and use galvanic replacement to deposit a thin Pd layer on the surface. Catalyzed by 1 wt%Pd/LaNi 5 , NEC absorbs 5.5 wt% H 2 in 0.7 h at 453 K and 7 MPa H 2, and perhydro-NEC desorbs 5.5 wt% in 2.1 h at 473 K and 0.1 MPa H 2 , which significantly outperforms Pd/Al 2 O 3 catalyst with the same Pd loading. The significantly promoted catalytic performance is attributed to the ample lattice hydrogen bonding sites and fast bulk hydrogen diffusion kinetics of LaNi 5 , which breaks the limitation of active hydrogen bonding sites due to the competitive adsorption of hydrogen and the organic molecule in surface catalysis. The active role of the lattice hydrogen bonding sites makes hydrogen storage materials highly attractive for hydrogen-related catalysis • Controlled preparation of a nano-sized hydride-based catalyst. • Highly-efficient catalysts for reversible hydrogen storage in a liquid organic hydrogen carrier. • Demonstration of lattice H-involved catalytical hydrogenation-dehydrogenation process.