Fabrication of layered double hydroxide spheres through urea hydrolysis and mechanisms involved in the formation.

The goal of this study is to prepare hydrotalcite pellets and validate their potential utility in catalysts and catalysts support. Hydrotalcite pellets were synthesized by urea hydrolysis. Urea hydrolysis can provide both carbonate as the intercalated anion and hydroxyl anions to form Mg–Al layered double hydroxide (LDH) with carbonate intercalation. Urea hydrolysis was also used to generate NH which plays a critical role in the process of synthesis hydrotalcite pellets. Mechanism of the formation hydrotalcite pellets was also discussed. The as-prepared samples were well characterized by X-ray diffraction, scanning electron microscopy, transmission electronic microscope, N adsorption/desorption, and Fourier transform infrared spectroscopy, respectively. The results revealed that the hydrotalcite pellets were well-crystallized and formed by self-assembly of hexagonal platelets LDHs. The present work suggests that it is possible to grow hydrotalcite pellets directly through one-step aqueous solution-phase chemical route under controlled conditions. [ABSTRACT FROM AUTHOR]