Preparation of platinum nanoparticles immobilized on ordered mesoporous Co3O4–CeO2 composites and their enhanced catalytic activity

Abstract

Using mesoporous silica KIT-6 as a template, ordered mesoporous Co₃O₄–CeO₂ composites with different contents of cobalt were prepared via the hard template method. Uniform Pt nanoparticles stabilized by polyamidoamine (PAMAM) dendrimers were immobilized on different Co₃O₄–CeO₂ composites, resulting in Pt-based supported catalysts. The prepared materials were characterized by several techniques such as transmission electron microscopy (TEM), nitrogen physical adsorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and energy dispersion X-ray analysis (EDX). The results showed that the Co₃O₄–CeO₂ composites have a regular pore structure and high crystallinity. Moreover, the specific surface area of Co₃O₄–CeO₂ reached 135.04 m² g⁻¹ for 10 mol% of cobalt (Co/(Co + Ce)). The introduction of cobalt could improve the structure of the supports and enhance the catalytic efficiency for the prepared Pt-based supported catalysts. The catalytic performances were evaluated by the reduction of 4-nitrophenol as monitored by UV-Vis spectra. In a comparison of the catalysts with different cobalt contents, it was found that Pt/meso-CeO₂Co10 possessed the highest catalytic performance as well as good reusability.