Pt-Embedded-Co3O4 hollow structure as a highly efficient catalyst for toluene combustion

Abstract

Pt embedded Co₃O₄ hollow structure nanocomposites (Pt@Co₃O₄) were prepared using a facile metal–organic frameworks (MOFs) sacrificial strategy. The encapsulated Pt catalyst demonstrated an excellent performance for toluene combustion in comparison with a Pt catalyst that was located outside of Co₃O₄ (Pt/Co₃O₄) and a bare Co₃O₄ catalyst. The superior performance can be ascribed to the interaction between Pt and Co₃O₄, along with the Pt being present in the lower oxidation state, the low-temperature reducibility and the rich surface-active oxygen species. The Pt embedded Co₃O₄ hollow structure has a greater number of available oxygen vacancies, which boosts the mobility of the active oxygen species. A possible reaction pathway was also proposed based on in situ diffusion reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra, and it was found that the chemically adsorbed toluene was oxidized to surface intermediates (benzyl alcohol, benzaldehyde and benzoate), and finally completely oxidized into CO₂ and H₂O. This study provides an effective strategy for the design of an advanced embedded catalyst.