Catalytic hydrogenation of phenanthrene over NiMo/Al2O3 catalysts as hydrogen storage intermediate

• Phenanthrene is suggested for the first time as liquid organic hydrogen carrier for hydrogen storage.
• Preparation of supported binary transition-metal catalyst on the alumina by coprecipitation.
• The NiMo catalyst showed high hydrogenation abilities of strong aromatic saturation, good isomerization.
• Reaction pathways of phenanthrene was proposed for NiMo/Al2O3 catalyst.

Hydrogen storage as an expanding research topic was investigated to discover and study new materials. However, phenanthrene (PHE) for the deeply hydrogenation reaction and hydrogen storage capacity can be used as a promising liquid organic hydrogen carrier. The hydrogenation of phenanthrene over the NiMo/Al2O3 catalysts was carried out in the 30 mL tubing-bomb micro-reactor. The catalysts were prepared by coprecipitation and characterized by X-ray diffraction(XRD), Scanning electronic microscopy coupled with Energy dispersive spectrometer (SEM-EDS), N2 physical adsorption, X-ray photoelectron spectroscopy(XPS), temperature programmed reduction (TPR) and temperature-programmed desorption (TPD) of H2. The results show that the interaction between the NiMo and the support increase with the calcination temperature and that Ni and Mo were present as Ni2+ and Mo4+ on the support. The hydrogenated products were analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). The results show that the catalyst calcinated at 600 °C, exhibits excellent high activity performance and the hydrogenation conversion of phenanthrene over the catalyst can reach above 70% at 400 °C. The selectivity of octahydrophenanthrene (OHP), octahydroanthracene (OHA), tetrahydrophenanthrene (THP) and dihydrophenanthrene (DHP) are 9.07%, 34.84%, 18.36% and 32.85%. The reaction pathway of phenanthrene hydrogenation is proposed.