The improved activity of Co3O4 nanorods using silver in the catalytic oxidation of toluene.

Co3O4 nanorods with diameters of ~0.15 μm and lengths of ~1 μm were prepared using a hydrothermal method via the assembly of microcrystals and tested in the catalytic oxidation of toluene. The catalytic performance of Co3O4 nanorods was improved by the addition of Ag at various concentrations, and the 7% Ag/Co3O4 catalyst achieves a toluene conversion of 90% at 256 °C with a space velocity of 78,000 mL g−1 h−1, which is much lower than that of the pristine Co3O4 (269 °C). The addition of Ag promoted the activation of the surface oxygen species and the formation of more oxygen vacancies, improving the relative low-temperature reducibility of Co3O4, which is favorable for toluene oxidation. Moreover, the 7% Ag/Co3O4 catalyst showed an excellent stability for toluene oxidation at 250 and 260 °C for 50 h under the same conditions.