An egg-shell bifunctional CeO₂-modified NiPd/Al₂O₃ catalyst for petrochemical processes involving selective hydrogenation and hydroisomerization

The catalytic performance during the 1-butyne hydrogenation using two reduced Al₂O₃-supported Pd-based catalysts was carried out in a total recirculation system with an external fixed-bed reactor. The lab-prepared egg-shell NiPd/CeO₂-Al₂O₃ catalyst (NiPdCe) with Pd loading = 0.5 wt%, Ni/Pd atomic ratio = 1 and CeO₂ loading = 3 wt% was synthesized and characterized, and it was compared with an egg-shell Al₂O₃-supported Pd based commercial catalyst (PdCC). The reduced catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The textural characteristics and ammonia temperature-programmed desorption profiles of the fresh (unreduced) catalysts were also obtained. Both catalysts show high 1-butyne conversion and selectivity to 1-butene, but the catalysts also present important differences between hydroisomerizing and hydrogenating capabilities. NiPdCe catalyst shows higher capability for hydroisomerization reactions, while the PdCC catalyst exhibits higher hydrogenating capability. The observed catalytic performances can be interesting for some industrial processes and can provide a guideline for the development of a Pd-based catalyst with specific catalytic properties.