Hierarchical porous Pt/Hβ catalyst with controllable acidity for efficient hydrogenation of naphthalene

Abstract

A series of hierarchical porous Pt/Hβ catalysts with different mesopores-acidity were synthesized without using secondary template. The pore structures of the catalysts were altered by constructing mesopores through alkali etching to reduce the mass transfer resistance. Moreover, the metal-support interaction (MSI) was optimized to improve the dispersion of the Pt metal particles. The smaller metal species could expose more active sites during the hydrogenation process, along with a more pronounced electron-deficiency effect. Furthermore, the effect of acid sites distribution on the hydrogenation reaction path and product distribution were also investigated. The strong acid-mesopores-metal factor (X) was defined to describe the relationship with the yield of decalin. The yield of decalin was well correlated with a high R2 value of 0.97. The Pt/Hβ-75 catalyst showed the best synergistic effect between acidity, mesopore and Pt species, leading to the optimal naphthalene conversion (96.7%) and higher yield of decalin (76.7%) at a relatively low temperature, which exhibited a better activity than other catalysts reported in literature for hydrogenation of naphthalene at a similar reaction condition. Besides, the hydrogenation reaction mechanism of naphthalene over Pt supported catalysts was further investigated by density functional theory, and the effect of Pt NPs size on the catalytic reaction process and activity was preliminarily revealed.