Layered hydroxide nickel benzoates: hydrothermal synthesis, structure characterization, and exfoliation reaction

This paper introduces two hydrothermally synthesized layered hydroxide nickel benzoates with the layered basic metal salt structures of basal spacings of 1.71 and 1.48 nm and their exfoliation reactions. These inorganic-organic hybrid layered compounds were characterized with XRD, FTIR, TG-DTA, SEM, SAED, and TEM. The 1.71 nm layered phase is a low temperature stable phase and has lattice parameters of a=0.7017(1)nm, b=0.3495(0)nm, c=1.763(7)nm, α=γ=90°, and β=101.6(6)°. The 1.48 nm layered phase is a high temperature stable phase and has lattice parameters of a=0.6277(2)nm, b=0.3678(2)nm, c=1.514(1)nm, α=γ=90°, and β=97.35(0)°. The benzoate anions in the interlayer space are coordinated to Ni(II) with unidentate and bidentate binding modes in the 1.71 nm layered phase, and with only bidentate binding mode in the 1.48 nm layered phase. These hybrid layered phases were exfoliated into their nanosheets in organic solvents, which gave a new category of inorganic-organic hybrid nanosheets. The exfoliation reactions are dependent on the structures and chemical compositions of the hybrid layered phases, as well as the molecule structures of the organic solvents used in the exfoliation.