121st General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code MAT.P-357
Subject Hydrothermal synthesis of high-crystalline layered double hydroxides via phase transformation from brucite layers
Authors Jinseop Shin, Tae-Hyun Kim, Jae-Min OH*
Department of Chemistry and Medical Chemistry, Yonsei University, Korea
Abstract Layered double hydroxide (LDH), also known as synthetic hydrotalcite, consists with divalent and trivalent metal hydroxide layers and interlayer anions. LDHs were typically synthesized by coprecipitation method with mixed metal solutions and alkaline solution. Meanwhile, brucite (Mg(OH)2) and gibbsite (Al(OH)3) were utilized to synthesize LDHs in previous reports. In this study, we synthesized LDHs with brucite and aluminum nitrate solution as Mg2+ and Al3+ precursor, respectively. The mixed suspension was transferred to Teflon-lined autoclave and hydrothermally treated (150℃) for 12 h in order to synthesize high-crystalline LDHs and identify the phase transformation mechanism from brucite to LDHs. We collected 30 mL of suspension at designed time points (1.5, 2.3, 2.7, 3, 4 and 12 h) from the hydrothermal reactor. The samples were collected with centrifugation (12,000 rpm, 10 min) and washed several times with deionized water, and then lyophilized. From the powdered X-ray diffraction (PXRD) patterns and high resolution-transmission electron microscope (HR-TEM) images showed the successful phase transformation from brucite to LDHs. Energy dispersive spectroscopy (EDS) assisted TEM was utilized for the identification of atomic distribution of the brucite and LDH particles. At the early stage, Al moieties were observed in the edge of hexagonal brucite particles. Afterwards, Al atoms were homogeneously existed in brucite platelets. The size and morphology of prepared samples were evaluated with scanning electron microscopy (SEM). To quantify and investigate the behavior of metal atoms at the supernatant and precipitate of the samples, we carried out using inductively coupled plasma-optical emission spectrometer (ICP-OES).
E-mail jsshin1013@yonsei.ac.kr