Effect of nickel-based catalysts with nanolamellar structure on catalytic hydrogenation of pyrene: Combining experiment and calculation

Coal tar contains a large number of polycyclic aromatic hydrocarbons, which can be converted into fuel or chemicals by catalytic hydrogenation to effectively improve the added value of coal tar. In the hydrogenation reaction of PAHs, the development of catalyst and the exploration of reaction mechanism are very important. So, in this study, using ZSM-5 and MCM-41 molecular sieve as carrier, a series of nickel-based catalysts with special morphology were synthesized by hydrothermal method, and the structure and composition of the catalysts were analyzed by a series of advanced characterization methods (such as XRD, SEM, and NH3-TPD, etc.). Catalytic hydrogenation experiments were carried out with pyrene polycyclic aromatic hydrocarbon model compound. The results showed: the active metal nickel is coated on the surface of the carrier with a dense nanosheet morphology, which changed the pore structure and acidity of the molecular sieve support, and effectively increased the catalytic activity of the molecular sieve for the hydrogenation of pyrene. Especially MCM-41 catalyst, with the loading of Ni, the mesoporous pore capacity increases from 0.265 cm3/g to 0.320 cm3/g, and strong acid peaks appear obviously. In addition, the hydrogenation conversion rate of pyrene reached 64.56 % from 12.68 % and the deep hydrogenation rate reached 56.83 % from 16.24 %. Meanwhile, the reaction path of pyrene hydrogenation was calculated using Gaussian software. Combined with the structure of catalyst, experimental data and calculation results, analyzed the action mechanism of catalyst, which provides a theoretical basis for the design and development of the subsequent PAHS catalyst.