Sand flower layered double hydroxides synthesized by co-precipitation for CO2 capture: Morphology evolution mechanism, agitation effect and stability

• Sand flower LDHs have best CO2 adsorption ability.
• The formation mechanism of sand flower LDHs is explored and discovered.
• Mechanical stirring has great effect on the sand flower LDH formation.
• The stability of the formed sand flower LDHs is related to treatment conditions.

Magnesium–aluminum layered double oxides (Mg–Al-LDO) derived from calcination of layered double hydroxides (LDH) is one of the most capable candidates for CO2 capture. LDHs with sand flower and dense layered morphology are prepared by co-precipitation method at pH = 10 under different condition with and without stirring. The sand flower LDH prepared with stirring has better CO2 adsorption performance. Additionally, the sand flower morphology under calcination can be preserved very well, while the morphology can only remain stable below 100 °C after hydrothermal treatment and reconstruction. The formation process of the sand flower LDH is investigated in detail and the related morphology evolution mechanism is proposed. This study can provide insight into the effect of mechanical interaction on chemical reaction and give a new way to control the morphology of layered materials.

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