Calcination system-induced nanocasting synthesis of uniform Co3O4 nanoparticles with high surface area and enhanced catalytic performance

Abstract

Co₃O₄ catalytic materials with varying mesoporous periodicity and crystallinity have been successfully synthesized via a calcination system-induced nanocasting method. N-Co₃O₄ with uniform nanoscale morphology, high specific surface area, and large pore size distribution was obtained in an open system as a calcination process, while M-Co₃O₄ with long-range mesoporous periodicity and high crystallinity was synthesized using a closed system as the calcination condition. The control of the mesostructure and morphology was carried out by tuning the diffusion rate of the cobalt precursor in the template channel resulting from the different escape rates of the decomposed byproducts via the varied calcination containers. The CO oxidation testing indicated that N-Co₃O₄ exhibited better catalytic performance than that of M-Co₃O₄. The difference in activity could be attributed to the uniform nanoscale structure of N-Co₃O₄, which mesoporous M-Co₃O₄ lacked. N-Co₃O₄ had a better performance for CO oxidation due to the uniform nanoparticle structure, higher specific surface area, larger pore size distribution, abundant active oxygen species and Co³⁺ cationic species on the surface, which accelerated the adsorption and diffusion of reactant molecules and finally improved the reaction activity of N-Co₃O₄. The resulting catalytic behaviors lead to a better understanding of designing and using such metal oxides for a number of catalytic applications.