A thermodynamically stable layered double hydroxide heterostructure

Abstract

A novel heterostructure was synthesised via the intercalation of 4-nitrophenolate (4-NP) into [LiAl₂(OH)₆]Cl·xH₂O ([Li-Al-Cl]). Its interlayer spaces are alternatively occupied by 4-NP and chloride ions. The intercalate is structurally analogous to staging intermediates reported previously. However, data obtained from time-resolved in situ energy-dispersive X-ray powder diffraction clearly differentiate it from a reaction intermediate. The [Li-Al-Cl–4-NP] heterostructure is formed as a thermodynamically stable product when [Li-Al-Cl] is treated with a small excess of 4-NP over an extended period of time at elevated temperatures (above 70 °C). The heterostructural compound exhibits selective anion exchange when reacted with a range of organic and inorganic anions.