PtNi catalysts prepared via borohydride reduction for hydrogenation of benzene

• Published in: Journal of catalysis Vol. 265; no. 1; pp. 63 - 71
• Main Authors: Abu Bakar, N.H.H., Bettahar, M.M., Abu Bakar, M., Monteverdi, S., Ismail, J., Alnot, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2009; Elsevier; Elsevier BV
• Subjects: Catalysis; Catalysts; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Hydrocarbons; Hydrogenation; Hydrogenation of benzene; Impregnation technique; Metals; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Pt/Ni bimetallic nanoparticles; Silica support; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Impregnation technique; Silica support; Hydrogenation of benzene; Pt/Ni bimetallic nanoparticles; Binary compound; Support; Nanoparticle; Surface segregation; Metal ion; X ray; Hydrogenation; Silica; Supported catalyst; Chemical reduction; Surface properties; Photoelectron spectrometry; Chemical reactivity; Scanning electron microscopy; Catalytic reaction; Metal particle; X ray diffraction; Heterogeneous catalysis; Impregnation; Transmission electron microscopy; Benzene; Preparation; Alloying; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2009.04.011

Pt/Ni–silica catalysts were prepared via co and step impregnation using NaBH 4 as a reducing agent. Pt 55Ni 45-CI (co-impregnated) exhibited superior reactivity compared to the monometallic catalysts. Alloying and Pt segregation may contribute to this enhanced activity. Pt/Ni supported on silica catalysts were synthesized via co-impregnation (CI) and step-impregnation (SI) techniques using NaBH 4 as the metal ions reducing agent. They were characterized by H 2-TPR and H 2-TPD, XRD, TEM, SEM and EDSX analyses as well as tested for the hydrogenation of benzene. The preparation method employed facilitates the formation of totally reduced pure metal or bimetallic metal particles on the surface and catalytic properties are governed by both the Pt/Ni ratio and mode of preparation. Co-impregnated catalysts exhibit a synergistic effect when a moderate amount of Pt is available: Pt 55Ni 45-CI catalyst was more active than both the pure monometallic catalysts. XRD and SEM equipped with EDSX lead us to believe that alloying occurs in the catalyst. Furthermore, surface segregation of Pt on the alloys as proven by XPS also contributes to this enhanced reactivity. In contrast to co-impregnated catalyst, all the step-impregnated catalysts show low catalytic reactivity when compared to pure Pt.