Design of Co₃O₄@SiO₂ Nanorattles for Catalytic Toluene Combustion Based on Bottom-Up Strategy Involving Spherical Poly(styrene-<i>co</i>-acrylic Acid) Template

• Main Authors: Anna Rokicińska, Magdalena Żurowska, Piotr Łątka, Marek Drozdek, Marek Michalik, Piotr Kuśtrowski
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Catalysts
• Subjects: volatile organic compounds; toluene; core–shell structures; spherical polymer templates; Co₃O₄
• Online Access: https://www.mdpi.com/2073-4344/11/9/1097

Bearing in mind the need to develop optimal transition metal oxide-based catalysts for the combustion of volatile organic compounds (VOCs), yolk-shell materials were proposed. The constructed composites contained catalytically active Co₃O₄ nanoparticles, protected against aggregation and highly dispersed in a shell made of porous SiO₂, forming a specific type of nanoreactor. The bottom-up synthesis started with obtaining spherical poly(styrene-<i>co</i>-acrylic acid) copolymer (PS30) cores, which were then covered with the SiO₂ layer. The Co₃O₄ active phase was deposited by impregnation using the PS30@SiO₂ composite as well as hollow SiO₂ spheres with the removed copolymer core. Structure (XRD), morphology (SEM), chemical composition (XRF), state of the active phase (UV-Vis-DR and XPS) and reducibility (H₂-TPR) of the obtained catalysts were studied. It was proven that the introduction of Co₃O₄ nanoparticles into the empty SiO₂ spheres resulted in their loose distribution, which facilitated the access of reagents to active sites and, on the other hand, promoted the involvement of lattice oxygen in the catalytic process. As a result, the catalysts obtained in this way showed a very high activity in the combustion of toluene, which significantly exceeded that achieved over a standard silica gel supported Co₃O₄ catalyst.