Morphology-controlled hydrothermal synthesis of MnCO3 hierarchical superstructures with Schiff base as stabilizer

MnCO3 with hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like were synthesized in water/ethanol system under environment-friendly hydrothermal condition. In the synthesis process, the CO2 in atmosphere was used as the source of carbonate ions and Schiff base was used as shape guiding-agent. The different superstructures of MnCO3 could be obtained by controlling the hydrothermal temperature, the molar ratio of manganous ions to the Schiff base, or the volume ratio of water to ethanol. A tentative growth mechanism for the generation of MnCO3 superstructures was proposed based on the rod–dumbbell–sphere model. Furthermore, the MnCO3 as precursor could be further successfully transferred to Mn2O3 microstructure after heating in the atmosphere at 500 °C, and the morphology of the Mn2O3 was directly determined by that of the MnCO3 precursor.

Graphical abstractMnCO3 microcrystals with hierarchical superstructures were synthesized by using the CO2 in atmosphere as carbonate ions source and Schiff base as shape guiding-agent in water/ethanol system under hydrothermal condition.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The most interesting in this work is the use of the greenhouse gases CO2 in atmosphere as carbonate ions source to precipitate with Mn2+ for producing MnCO3 crystals. ► This work is the first report related to the small organic molecule Schiff base as shape guiding-agent to produce different MnCO3 hierarchical superstructures. ► We are controllable synthesis of the MnCO3 hierarchical superstructures such as chrysanthemum, straw-bundle, dumbbell and sphere-like microcrystals. ► The as-prepared MnCO3 could be used precursor to fabricate the Mn2O3 hierarchical superstructures after thermal decomposition at high temperature.