Manipulating morphology and surface engineering of spinel cobalt oxides to attain high catalytic performance for propane oxidation

The selective synthesis of nanomaterials with different morphologies and crystal facets is of great significance for catalytic properties and practical applications. We report a strategy for controllable fabrication of hierarchical Co3O4 materials with various morphologies (ellipsoidal, flowerlike, book-shaped, spindlelike) and study their catalytic properties in propane oxidation. Co3O4-B (book-shaped) is found to exhibit the highest propane oxidation rate (0.86 × 10-8 mol m−2 s−1) and the highest turnover frequency (TOF = 11.49 × 10−3 s−1) at 220 °C. This confirms that Co3O4-B provides a higher specific surface area, a highly exposed {1 1 0} facet, and abundant Co3+ cations, which make it exhibit favorable low-temperature reducibility and oxygen mobility and thus improve its catalytic activity. In situ diffuse reflectance infrared Fourier transform spectroscopic analysis reveals that the intermediates, such as carboxylate and carbonate species, are involved in propane oxidation. Furthermore, Co3O4-B shows high water-resistance performance, and no significant deactivation is observed after long-term stability and reusability tests.