Mg/Al-CO3 layered double hydroxide nanorings

Abstract

Mg/Al-CO₃ Layered Double Hydroxide (LDH) nanorings with a 750 nm exterior diameter and 250 nm interior diameter were synthesized in an organic/water solvent system via a urea hydrolysis method, using Mg₁₀(OH)₁₈Cl₂·5H₂O nanowires as precursors. X-Ray diffraction and Fourier-transform infrared spectroscopy clearly revealed the nanorings to comprise Mg/Al-CO₃ LDH. The character of the precursor materials and the ratio of organic solvents to water used for reaction played crucial roles in determining the final ring-like morphology. A possible mechanism was proposed for the LDH nanoring formation. The unique LDH nanorings exposed a higher specific surface area and larger pore volume than plate-like and flower-like analogues, and thus were further explored for their catalytic activity using the Knoevenagel reaction between benzaldehyde and diethyl malonate as a probe reaction. The ring-like structure displayed a significantly enhanced catalytic performance above other analogues.