Uniform nanoparticles of hydrotalcite-like materials and their textural properties at optimized conditions of urea hydrothermal treatment

Abstract

The efficient urea hydrothermal synthetic technique for hydrotalcite (HTlc) was optimized to prepare uniform HTlc nanoparticles that exhibit high performance in variety of applications. Experimentally, a series of single-phase Mg–Al HTlc(s) with good textural properties was successfully obtained under optimized urea/metals molar ratio and hydrothermal aging conditions. The X-ray analysis confirmed the purity and the high crystallinity of the prepared HTlc(s). The chemical composition, crystallinity, and textural properties of the optimized HTlc(s) were investigated and compared to those of the conventionally prepared HTlc(s). The increase in the urea concentration decreased the crystallite size of the HTlc(s). The reduction in the hydrothermal aging time led to a narrow particle size distribution. The greatest uniformity of particle size was achieved at a urea/metals molar ratio of 3.0 and at a hydrothermal aging time of 12h. An increase in the urea/metals molar ratio to 3.0 increased the micropore volume available for adsorption, and the BET surface area consequently increased. The hydrothermal aging of the HTlc(s) significantly decreased the amount of nitrogen the samples adsorbed.