Regulation of a Ni3Sn2 intermetallic catalyst using highly dispersed Pd species to boost propyne semi-hydrogenation

Abstract

Tailoring adsorption behaviors and promoting activation of hydrogenation on Ni active sites are significant but challenging for designing high-performance Ni-based catalysts for selective hydrogenation. Herein, we propose to introduce highly dispersed Pd species into a Ni₃Sn₂ intermetallic catalyst to enhance the catalytic performance of propyne semi-hydrogenation. Detailed characterization studies, including X-ray diffraction and high-resolution transmission electron microscopy, indicate that the introduction of Pd species maintains the Ni₃Sn₂ crystal structure in the fabricated (Ni_0.9Pd_0.1)₃Sn₂ catalyst, while regulating the electronic structures of Ni sites, and thus weakens the propylene adsorption. Furthermore, combined with kinetic studies and theoretical calculations, the highly dispersed Pd species are demonstrated to clearly promote the activation of hydrogenation and restrain the C–C coupling reaction. As such, the propyne conversion and propylene selectivity are simultaneously improved (i.e., 96.0% propylene selectivity at 94.6% of propyne conversion) on the (Ni_0.9Pd_0.1)₃Sn₂ catalyst as compared with the Ni₃Sn₂ catalyst. These findings presented here indicate that the introduction of noble-metal species onto Ni-based intermetallic catalysts is an effective strategy for enhancing the activity while retaining high selectivity for selective hydrogenation.