Mixed Metal Oxide by Calcination of Layered Double Hydroxide: Parameters Affecting Specific Surface Area

Abstract

Mixed metal oxide (MMO) is one of the widely utilized ceramic materials in various industries. In order to obtain high performance, the specific surface area of MMO should be controlled. Calcination of layered double hydroxide (LDH) is a versatile way to prepare MMO with homogeneous metal distribution and well-developed porosity. Although researchers found that the specific surface area of LDH-originated MMO was relatively high, it had not been systematically investigated how the surface area is controlled under a certain parameter. In this review, we summarized LDH-originated MMO with various starting composition, calcination temperature, and pore developing agent in terms of specific surface area and porosity. Briefly, it was represented that MMOs with Mg-Al components generally had higher specific surface area than Mg-Fe or Zn-Al components. Calcination temperature in the range 300–600 °C resulted in the high specific surface area, while upper or lower temperature reduced the values. Pore developing agent did not result in dramatic increase in MMO; however, the pore size distribution became narrower in the presence of pore developing agents.

Fe-Ce/Layered Double Hydroxide Heterostructures and Their Derived Oxides: Electrochemical Characterization and Light-Driven Catalysis for the Degradation of Phenol from Water

“…reported the mixed oxides obtained via the calcination of Zn/(Al + Fe)/LDHs as photocatalysts with a high activity towards the photodegradation of phenol and p-cresol [ 22 ]. The MMOs derived from Zn-LDHs calcinated at 300–600 °C contain additional phases of ZnO, have higher crystallinity, and a specific surface area that facilitates the charge carrier transfer and improves photocatalytic performances [ 23 ]. Recently, ZnFe-MMOs or ZnTi-MMOs have been synthesized via the calcination of their ZnFe-LDH and ZnTi-LDH precursors at different temperatures and used with very good performances in water purification processes under simulated solar light irradiation [ 24 , 25 , 26 ].…”

Exfoliated Layered Metal Oxide-Supported Ruthenium Catalysts for Base-Free Oxidation of 5-Hydroxymethylfurfural into a Renewable Bioplastic Precursor

“…In addition, the XPS analysis indicates that the hydroxyl species (O OH ) found on Ru(3)/ESV-LDC originated from Mg­(OH) 2 and Al­(OH) 3 , as revealed in the Mg 2s and Al 2p XPS spectra, respectively (Figure S5). The presence of mixed metal hydroxides in Ru(3)/ESV-LDC, but not Ru(3)/ESV-LDO, should be attributed to higher S BET of the former than the latter, which correlate with the number of edge and corner sites, basicity, and catalytic activity of LDO …”

“…The presence of mixed metal hydroxides in Ru(3)/ESV-LDC, but not Ru(3)/ESV-LDO, should be attributed to higher S BET of the former than the latter, which correlate with the number of edge and corner sites, basicity, and catalytic activity of LDO. 46 It was postulated that, under a homogeneous base-free system, the basic sites are of importance for alcohol group deprotonation, while the acidity facilitates activation of the aldehyde group. 10,47 The distribution of basic and acidic sites of various strengths is presented in Figure S6 and Table 2.…”

In-Depth Thermal, Microstructural and Photoluminescence Analysis of Mesoporous ZnO/ZnAl2O4-MMO: The Effect of Molar Ratio

“…1a). 28 Continuously, the aforementioned transformation was accomplished via thermal process at a temperature of 400 °C for 60 min and heating rate of 5 °C min −1 . A schematic illustration of the preparation procedures is illustrated in Fig.…”