Synthesis of α-Al2O3 at mild temperatures by controlling aluminum precursor, pH, and ethylenediamine chelating additive

Role of pH, Organic Additive, and Chelating Agent in Gel Synthesis and Fluorescent Properties of Porous Monolithic Alumina

“…The survey spectra of the Al 2 O 3 samples contained Al 2p and O 1s peak according to an XPS PDF handbook. It is known that the Al 2p3/2 orbital in α type alumina is presented at 74.2 eV, which was ascribed to Al 3+ in alumina . The binding energy of Al 2p core level is the same for all alumina samples prepared at various pHs as shown in Figure a.…”

“…The binding energy of Al 2p core level is the same for all alumina samples prepared at various pHs as shown in Figure a. Usually, for the O 1s level, a higher metal–OH peak indicates that the powders are more hydrophilic . However, only a single peak appears in S5 and S6 samples at around 531 eV, which is ascribed to Al–O.…”

“…These results suggest the significant effect of the pH on the crystallinity and morphology. This is because the wet chemistry processing is based on several reaction processes such as hydrolysis and polymerization . In the acidic environment of pH < 7, the rate of hydrolysis is controlled by the hydronium ion in acid precursor, and so the content of water is low because of rapid formation of H 3 O + .…”

Enhanced Conversion in the Direct Synthesis of Diethyl Carbonate from Ethanol and CO2 by Process Intensification

“…7 a), 2q = 7.2°(200), 10.2°(220), 12.5°(222), 16.2°(420), 21.8°(442), 24°(622), 26.2°(640), 27.2°(642), 30°(644), 30.9°(660), 32.6°(840), and 33.4°(842) JCPDS 39-0222 [49]. In addition, alumina phases (2q = 25.6°, 35.2°, and 37.8°JCPDS 88-0826) [50] were not observed in the material synthesized on the Al 2 O 3 support. Therefore, the results confirmed the formation of a zeolite layer on the inner surface of the supports, which is expected to allow the selective separation of the produced water from the reaction system.…”