Novel Pt–Ni Bimetallic Catalysts Pt(Ni)–LaFeO 3 /SiO 2 via Lattice Atomic-Confined Reduction for Highly Efficient Isobutane Dehydrogenation

Abstract

In this study, a series of novel Pt–Ni bimetallic catalysts supported on LaFeO 3 /SiO 2 with different amounts of Ni were prepared by the lattice atomic-confined reduction of LaFe 1−x (Ni, Pt) x O 3 /SiO 2 perovskite precursors and applied in isobutane dehydrogenation to isobutene reaction. The catalysts were characterized by X-ray diffraction, H 2 -temperature-programmed reduction, Brunauer–Emmett–Teller analysis, transmission electron microscopy, energy dispersive X-ray, CO chemisorption, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The as-synthesized Pt–Ni bimetallic catalysts possessed smaller most probable particle size with tunable Pt–Ni interaction, depending on the Ni content. The catalyst with Ni content of 3.0 wt% showed excellent activity and stability (the isobutane conversion and isobutene selectivity remained at about 38% and 92%, respectively, after 310 min) for the isobutane dehydrogenation reaction. It also provided approximately six times turnover frequency of the catalyst without Ni. The excellent activity and stability of the 3.0 wt% Ni-containing catalyst can be attributed to its small metal nanoparticles with high dispersion and suitable Pt–Ni interaction. Moreover, the Pt(Ni)–LaFeO 3 /SiO 2 catalyst with Ni content of 3.0 wt% had been run for more than 35 h without obvious loss of activity, indicating its long-term stability, and the decrease in the Pt–Ni interaction that accompanied the formation of the FeNi alloy phase was thought to be responsible for the slight decrease in activity.