Bimetallic Pd-M (M = Pt, Ni, Cu, Co) nanoparticles catalysts with strong electrostatic metal-support interaction for hydrogenation of toluene and benzene

Abstract

Herein, we reported an effective method to synthesis a series of supported bimetallic Pd-M/SiO2 (M = Pt, Ni, Cu, Co) catalysts with highly exposed and well-alloyed nanoparticles via simultaneous strong electrostatic adsorption (co-SEA), which controlled metal precursors strongly anchored onto the oppositely charged support (SiO2) by changing the pH relative to the surface point of zero charge (PZC). The toluene and benzene hydrogenation were used as probe reactions to evaluate the catalytic hydrogenation activity performance of the Pd-M/SiO2 catalysts. Compared to the catalysts synthesized by the common technique simultaneous dry impregnation (co-DI), the co-SEA Pd-Ni/SiO2 catalyst exhibited the highest turnover frequencies (TOFs) of 3.7 s−1 for benzene hydrogenation and 3.2 s−1 for toluene hydrogenation. This was attributed to the large amount of electron-deficient Pdδ+ sites on the surface of SEA Pd-M/SiO2 that easily for electron-rich benzene and toluene to adsorb. Besides, the co-SEA catalysts produced well stability and reusability without significant decrease in the catalytic activity after six runs.