Seok Han Kim

Solvothermal/Hydrothermal Synthesis of Metal Oxides and Metal Powders with and without Microwaves

Anatase and Ca, Sr and Ca0.5Sr0.5 hydroxyapatites were synthesized by conventional-hydrothermal (C-H) as well asmicrowave-hydrothermal (M-H)methods.Microwave-assisted reactions led to accelerated syntheses of anatase but no such acceleration of reactions could be detected with the syntheses of hydroxyapatites because the crystallization of the latter materials occurred at very low temperature. Cu and Au metal powders were produced by using glucose, fructose or sucrose as reducing agents under C-H conditions at 160 ℃, where fructose and sucrose were found to be stronger reducing agents than glucose. The crystallinity of all the powders was characterized by powder X-ray diffraction, and morphology and particle sizes were determined by scanning or transmission electron microscopy Graphical Abstract Solvothermal/ Hydrothermal Synthesis of Metal Oxides and Metal Powders with and without Microwaves

Synthesis of zeolite rho: Aging temperature effect

This paper focuses on deciphering the gel aging temperature effect on the crystallization of zeolite rho(RHO). Increased gel aging temperature (from room temperature to 55°C and no aging) caused an increase in induction periods and decreased the crystallization rate during the synthesis of RHO. Other crystalline phases such as chabazite were formed along with increasing aging temperature. The largest crystal size of RHO increased proportionally to aging temperatures up to about 9 μm. These results suggest that aging temperature greatly affected the crystallization, the crystal sizes, the purity and the formed crystalline phases during the synthesis of zeolite rho. This study suggests that most of RHO nuclei are formed during gel aging and their formation is depressed by the increased aging temperatures.