Pd <sub>3</sub>P Nanoparticles Decorated P-Doped Graphene for High Hydrogen Storage Capacity and Stable Hydrogen Adsorption-Desorption Performance

The emergence of graphene provides a new research vector for the development of hydrogen storage materials. Herein, we firstly report a Pd3P nanoparticles decorated P-doped graphene material by a facile pyrolysis method for hydrogen storage. The size of Pd3P particles is distributed on the graphene surface uniformly in the range of 20-30nm. It has a high gravimetric density of hydrogen storage of 3.66wt% at mild conditions (298K, 4MPa). When the temperature drops to 253K, the hydrogen storage capacity increases to 3.94wt%; whereas at the pressure of 5.5MPa and 298K, the hydrogen storage capacity is up to 4.7wt%. The Pd3P nanoparticles decorated P-doped graphene has both physical and chemical hydrogen adsorption mechanisms during the hydrogen storage process. The hydride produced by chemical adsorption remains stable even at 498K, which is the main reason for 1.03wt% of the capacity loss during the hydrogen adsorption-desorption cycle. After 4 cycles of hydrogen adsorption-desorption at 298K and 4MPa, the effective hydrogen storage capacity of Pd3P nanoparticles decorated P-doped graphene is 2.63wt%, and the Pd3P nanoparticles on the graphene are evenly distributed with stable structure after cycles, which is conducive to the realization of reversible hydrogen storage.