A new route for local probing of inner interactions within a layered double hydroxide/benzene derivative hybrid material

Abstract

This paper presents the preparation and characterization of hybrid hydrotalcite-type layered double hydroxides (Zn_1−xAl_x(OH)₂HBS_x·nH₂O, with x = 0.33) where HBS is the 4-phenol sulfonate, with a detailed analysis of the grafting process of this organic entity onto the host lattice. As a set of the usual techniques (XRD, TG-DT/MS, FTIR and ²⁷Al MAS NMR) was used to characterize the hybrid materials, this work focuses on a joint study by X-ray photoelectron spectroscopy and some quantum-calculation modeling in order to highlight the nature of the interactions between the organic and the mineral sub-systems. For the as-prepared hybrid material, the main results lead to a quasi-vertical orientation of the organic molecules within the mineral sheets via H-bond stabilization. By heating the hybrid material up to 200 °C, the structure shrinks with the condensation of the organics; the different theoretical modeling done gives an energy-stable situation when a direct attachment of the HBS sulfonate group sets up with the mineral layers, in agreement with the recorded XPS experimental data.