Morphology effect of β-zeolite supports for Ni2P catalysts on the hydrocracking of polycyclic aromatic hydrocarbons to benzene, toluene, and xylene

Abstract Ni 2 P catalysts supported on nano-sized β (β-N) or micrometer-sized β (β-M) zeolites were prepared by temperature-programmed reduction, and their structural and chemical properties were analyzed by N 2 physisorption, transmission electron microscopy, X-ray diffraction, extended X-ray absorption fine structure, NH 3 temperature-programmed desorption, and CO uptake. The catalytic activity was tested at 653 K and 6.0 MPa in a fixed bed reactor for the hydrocracking of 1-methylnaphthalene (1-MN) into benzene, toluene, and xylene (BTX). In the hydrocracking, Ni 2 P/β-N showed better activity and stability for hydrocracking of 1-MN than Ni 2 P/β-M, with BTX yields of 42.3% and 30.5% for Ni 2 P/β-N and Ni 2 P/β-M, respectively. In addition, Ni 2 P/β-N maintained the stability in terms of catalytic activity and local structure, while Ni 2 P/β-M suffered from coke formation, particularly in the presence of heavy aromatics such as phenanthrene in the feed. The characterization results demonstrated that the β-N has abundant intercrystalline mesopores to provide better dispersion for Ni 2 P catalysts and accessibility toward acid sites, offering the proximity of the hydrogenation active center and the cracking sites. Kinetic analysis for the hydrocracking of 1-MN over the catalysts revealed that the Ni 2 P/β-N catalyst shows superior activity for both hydrogenation and cracking over the Ni 2 P/β-M catalyst.