Abstract: Herein, a bottom-down design is presented to successfully fabricate ZIF-derived Co₃O₄, grown in situ on a one-dimensional (1D) α-MnO₂ material, denoted as α-MnO₂@Co₃O₄. The synergistic effect derived from the coupled interface constructed between α-MnO₂ and Co₃O₄ is responsible for the enhanced catalytic activity. The resultant α-MnO₂@Co₃O₄ catalyst exhibits excellent catalytic activity at a T_90% (temperature required to achieve a toluene conversion of 90%) of approximately 229 ℃, which is 47 and 28 ℃ lower than those of the pure α-MnO₂ nanowire and Co₃O₄-b obtained via pyrolysis of ZIF-67, respectively. This activity is attributed to the increase in the number of surface-adsorbed oxygen species, which accelerate the oxygen mobility and enhance the redox pairs of Mn⁴⁺/Mn³⁺ and Co²⁺/Co³⁺. Moreover, the result of in situ diffuse reflectance infrared Fourier transform spectroscopy suggests that the gaseous oxygen could be more easily activated to adsorbed oxygen species on the surface of α-MnO₂@Co₃O₄ than on that of α-MnO₂. The catalytic reaction route of toluene oxidation over the α-MnO₂@Co₃O₄ catalyst is as follows:toluene → benzoate species → alkanes containing oxygen functional group → CO₂ and H₂O. In addition, the α-MnO₂@Co₃O₄ catalyst shows excellent stability and good water resistance for toluene oxidation. Furthermore, the preparation method can be extended to other 1D MnO₂ materials. A new strategy for the development of high-performance catalysts of practical significance is provided.

Key words: MnO₂@Co₃O_4, Toluene oxidation, Synergistic effect, Coupled interface, In situ DRIFTS