Synthesis, Characterization, and1H and71Ga MAS NMR Spectroscopy of a Novel Mg/Ga Double Layered Hydroxide☆

Abstract A new brucite-like layered Mg/Ga double hydroxide (LDH) of composition [Mg 0.174 Ga 0.256 (OH) 2 ](CO 3 ) 0.134 · m H 2 O was synthesized by coprecipitation at pH 10. The hydroxide and the mixed oxides resulting from its thermal decomposition at 523, 823 and 1073 K were characterized by X-ray diffraction, diffuse reflectance infrared spectroscopy, high-resolution solid-state nuclear magnetic resonance (MAS NMR), and thermogravimetric analysis. The surface properties of the solid (specific surface) and its basicity were also determined. The Mg/Ga LDH was found to be stable up to 523K and to decompose into a mixture of periclase MgO and amorphous Ga 2 O 3 at 823 K. Its changes with temperature were monitored by using 1 H and 71 Ga MAS NMR; 1 H MAS NMR spectra revealed the loss of interlayer OH groups supporting the brucite-like structure on calcination at 823K.