Decoration of graphene sheets with Pd/Al2O3 hybrid particles for hydrogen storage applications

• Al2O3/Pd hybrid nanoparticles were prepared for hydrogen storage.
• Al2O3/Pd pairs on graphene performed better than Pd on graphene.
• The improvement of the hybrid particles was explained by the hydrogen spillover.

In this work, we developed a heterogeneous catalyst consisting of Al2O3 nanoparticle and low amounts of Pd that markedly enhances the hydrogen uptake of reduced graphene oxide (RGO). The Pd/Al2O3 hybrid particles were prepared by ultrasound-assisted impregnation of PdCl2 in aqueous suspension of Al2O3 nanoparticles. Hybrid particles were immobilized onto the RGO support, giving Pd/Al2O3–RGO nanocomposites. It was shown that incorporation of 1 wt% heterogeneous catalyst (<0.3 wt% Pd) significantly increased the hydrogen storage capacity of RGO from 0.17 wt% to 0.31 wt%. This indicated a raise of hydrogen uptake by factor of 1.8 in RGO nanocomposite. The improving hydrogen storage capacity of RGO nanocomposites by change of Al2O3 particle size and Pd content was linked to activation of processes usually grouped as spillover.