Shape-controlled synthesis of MnCo complex oxide nanostructures via a polyol-based precursor route and their catalytic properties

A polyol-based precursor route was developed to synthesize MnCo complex oxide with well-defined morphologies, in which ethylene glycol (EG) was treated with metal acetates in the presence of poly(vinyl-pyrrolidone) (PVP). By varying the reaction temperature, the as-obtained precursor was readily regulated its morphologies, which could vary from nanospheres to hierarchically stacked nanoplates. The initial molar ratio of Mn-acetate to Co-acetate in EG solution played a crucial role in determining the chemical composition of the nano/microstructured precursor. On the basis of the experimental results, a possible growth mechanism for the nanostructured precursor was proposed. MnCo2O4 and CoMn2O4 could be obtained from their precursors without changing the morphologies by a simple calcination procedure. The synthetic methodology appears to be general and promises to provide an entryway into other complex oxide materials with various nano/microstructures. As an example of potential applications, the as-obtained MnCo mixed oxide nano/microstructures were used as catalyst in CO oxidation, and the effect of the morphology and composition on catalytic activities was investigated.

► Nanostructured MnCo complex oxides were prepared by a polyol-based precursor route. ► The morphology of precursors was tunable by adjusting reaction temperatures. ► The morphology evolution was controlled by kinetically driven crystallization process. ► The composition of samples was tunable by adjusting the proportion of raw materials. ► CO catalytic oxidiate of the samples with different shapes and compositions was studied.