On the role of size controlled Pt particles in nanostructured Pt-containing Al2O3 catalysts for partial oxidation of methane

• Published in: International journal of hydrogen energy Vol. 44; no. 50; pp. 27329 - 27342
• Main Authors: Araújo, Jesuina C.S., Oton, Lais F., Oliveira, Alcineia C., Lang, Rossano, Otubo, Larissa, Bueno, José M.C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18-10-2019
• Subjects: Alumina; CO-DRIFTS; Methane; Nanostructured; Oxidation; Platinum; Methane; Oxidation; Nanostructured; Platinum; Alumina; CO-DRIFTS
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2019.08.176

The effect of the Pt loadings and particles sizes on the stability of Pt(x wt%)/Al2O3 catalysts were investigated in the partial oxidation of methane (POM) reaction. The Al2O3 support was prepared by sol-gel method and different Pt loadings, varying from 0.5 to 2.0 wt% were incorporated to alumina through the incipient wetness impregnation method. The physicochemical features of the catalysts were determined by XRD, ICP-OES, Nitrogen-sorption, UV–Visible, H2-TPR, CO-DRIFTS, SEM-EDS, XPS and HRTEM techniques. The metal dispersion was evaluated in the cyclohexane dehydrogenation reaction. Lower Pt loadings resulted in well dispersed Pto nanoparticles with an enhanced activity in cyclohexane dehydrogenation and POM reactions. With increasing Pt loading to 2.0 wt%, the Pt nanoparticles of the Pt(2.0 wt%)/Al2O3 showed a methane conversion of 63% in 24 h of time on stream, and the catalyst was very selective to H2 and CO. Based on the HRTEM, XPS and Raman spectroscopy techniques, an increment in the Pt loadings evidenced an enrichment of Pto clusters on the surface, however, no heavy carbon deposits formation was observed.
[Display omitted]
•Partial oxidation of methane reaction over nanostructured Pt supported Al2O3.•XRD, Nitrogen-sorption, H2-TPR, CO-DRIFTS, SEM-EDS, XPS and HRTEM.•The metal dispersion evaluated in the cyclohexane dehydrogenation reaction.•The effect of the Pt particles sizes and loadings on the stability of catalysts.•Enrichment of Pto nanoparticles on the surface avoids heavy carbon deposition.