Gelification process to prepare phosphate modified alumina: Study on structure and surface properties

Synthesis and properties of thermostable γ-alumina prepared by hydrolysis of phosphide aluminum

“…The impregnation of phosphate solution on alumina would not result in the formation of AlPO 4 [32]. Morterra and co-workers [26] considered that the addition of phosphates by impregnation did not modify the phase transition from ␥-Al 2 O 3 to ␣-Al 2 O 3 , but have a positive effect on surface area and porosity only for the corundum phase obtained at temperature above 1450 K. As for Gu et al [27], who prepared phosphor doped ␥-Al 2 O 3 by gel, found that the addition of phosphate effectively improve the thermal stability and textural properties of alumina. Phosphors are considered a good phase stabilizer and structure modifier because the P 5+ ions in the tetrahedral sites of ␥-Al 2 O 3 interrupted the track of Al 3+ transformation.…”

“…The suspension was filtrated and washed with deionized water twice. The PAlOH sample was prepared by drying the filter cake at 373 K for 12 h. The PAl-773 was prepared by calcining PAlOH at 773 K for 3 h. A referenced pure alumina was prepared by gel method [27], denoted as Blank.…”

“…AP series of phosphormodified alumina with Morterra was prepared by impregnation [26]. G 5 series samples were phosphor-modified alumina prepared by Gu [27] through gelification. It shows that phosphor has an evident effect on restraining the loss of surface area, especially above 1273 K. Among three preparation methods, the specific surface area of PAl sample is similar to G 5 sample or even higher It has been reported that the addition of phosphor can improve the thermal stability of ␥-Al 2 O 3 and the introduction step determines the structure of phosphor-modified alumina after calcination [31].…”

“…Because phosphor is the residue of reaction, it homogeneously disperses in the ␥-Al 2 O 3 after calcination. When calcined at higher temperature, phosphor acts as structure stabilizer and gradually inhibits the sintering and phase transformation [27].…”

Gold Functionalized Supported Ionic Liquids Catalyst for CO Oxidation

“…The characterization by IR spectroscopy of the modified support compared to bare unmodified alumina ( Figure 2(A,B)) reveals a new band at 1100 cm −1 attributed to the P-O groups [27,28]. As claimed in the literature [29], the anions can be adsorbed in an oxide-water interface in an inner-or outer-sphere mode.…”