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

Abstract

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.