Pt/Al2O3La2O3 catalysts stable at high temperature in air, prepared using a “one-pot” sol–gel process: Synthesis, characterization, and catalytic activity in the partial oxidation of CH4

• Published in: Chemical engineering science 2021-01, Vol.229, p.115966, Article 115966
• Main Authors: Rocha, Kleper de O., Macedo, Wagner C., Marques, Clélia M.P., Bueno, José M.C.
• Format: Article
• Language: English
• Subjects: in situ XANES; Metal sintering; One-pot preparation; POM; Pt catalyst; Sol–gel
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2020.115966

[Display omitted] •Sol-gel “one-pot” step process provides Pt particles partially buried in the support.•Sol-gel “one-pot” process results in Pt nanoparticles highly resistant to sintering.•Only linearly bound CO species suggests defects on the Pt surface by interactions with the support.•H2/CO ratio in the POM reaction was influenced by La2O3 addition. Pt/Al2O3La2O3 catalysts were prepared by a “one-pot” sol–gel method, with different final synthesis temperatures. The catalysts were characterized by in situ X-ray absorption spectroscopy (XAS). The partial oxidation of methane (POM) reaction was used to evaluate catalyst stability. DRIFTS-CO analysis indicated the interaction of Pt with the support by Pt-O-(Al-O, La-O) bonds, which suppressed bridge CO adsorption. In situ POM-DXAS-MS analysis showed that after use in the POM reaction at about 1000 K and cooling to room temperature, the Pt/Al2O3La2O3 catalysts presented partial oxidation of Pt0, indicating the formation of a core–shell structure. The nanoparticles generated using the “one-pot” method showed higher Pt-O-Al type interaction with the support, relative to free Pt-O at the surface, resulting in high resistance to sintering in the POM reaction. The temperature used in the “one-pot” synthesis significantly influenced the Pt-O-Al interaction, which modified the resistance to sintering at 1073 K in air.