Partial hydrogenation of acetylene using highly stable dispersed bimetallic Pd–Ga/MgO–Al2O3 catalyst

Abstract

An effective and versatile synthetic approach is presented to produce highly dispersed bimetallic Pd–Ga catalysts that can be used as hydrogenation catalysts. Mg–Ga–Al-layered double hydroxide (LDH) was synthesized in situ on the surface of spherical alumina to obtain MgGaAl-LDH@Al2O3 precursor, followed by the introduction of PdCl42-. The positive charge of MgGaAl-LDH layer offers an opportunity to realize uniform dispersion of PdCl42-, which facilitates the formation of bimetallic Pd–Ga nanoalloys. Upon thermal reduction of PdCl42-/MgGaAl-LDH@Al2O3 precursor, highly stable dispersed bimetallic Pd–Ga/MgO–Al2O3 catalysts were obtained. Owing to high dispersion and synergistic effect of bimetallic nanoalloys, Pd–Ga/MgO–Al2O3 catalysts exhibited comparable activity and much higher selectivity compared with the monometallic Pd/MgO–Al2O3 in partial hydrogenation of acetylene. More significantly, this good catalytic performance can be totally retained after three times recycling due to the net trap confinement effect, which suppressed the migration and aggregation of bimetallic Pd–Ga nanoalloys.