Highly Dispersed PdNPs/α-Al2O3 Catalyst for the Selective Hydrogenation of Acetylene Prepared with Monodispersed Pd Nanoparticles

Pd nanoparticles (PdNPs) stabilized by methyl cellulose (MC) were synthesized in an aqueous solution, which are monodispersed nanoparticles. PdNPs/alpha-Al2O3 catalyst was prepared with monodispersed PdNPs and showed better catalytic performance than Pd/alpha-Al2O3 catalyst prepared by the incipient wetness impregnation method using Pd(NO3)(2) as a precursor. The catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that monodispersed PdNPs were spherical or elliptical nanoparticles with exposed (111) and (100) facets, and the PdNPs/alpha-Al2O3 catalyst showed a more concentrated distribution of Pd particles on the surface of alpha-Al2O3 support than the Pd/alpha-Al2O3 catalyst. The preparation method achieved the highly dispersed PdNPs/alpha-Al2O3 catalyst with smaller Pd particle size and decreased the aggregation of Pd active sites, which was responsible for higher acetylene conversion and ethylene selectivity.