A modified sol–gel method for low-temperature synthesis of homogeneous nanoporous La1−x Sr x MnO3 with large specific surface area

Abstract

A modified sol-gel (MSG) method was developed to synthesize perovskite La 1-x Sr x MnO 3 (x = 0.2, 0.4, 0.6, 0.8) with large specific surface area that allows for control of their particle size from the micrometer level to the nanometer level with novel nanoporous structure. The MSG method utilized carbon black (Vulcan XC-72R) as a poreforming material during the preparation process. Two important process parameters, the calcination temperature and the pore former material addition, were investigated to control the size of the La 1-x Sr x MnO 3 particles. The phase evolution of La 1-x Sr x MnO 3 powders was investigated by thermogravimetric analysis (TG/DSC) and X-ray diffraction pattern. The results showed that the pure La 0.6 Sr 0.4 MnO 3 phase has been obtained at about 550°C in air, which is lowered around 150°C comparing to conventional sol-gel method. In scanning electron microscope studied, it presented novel homogeneous nanoporous morphology with the average particle size from 30 to 100 nm. Based on the Brunauer-Emmett-Teller method analysis, the specific surface area of La 1-x Sr x MnO 3 was significantly influenced by the calcination temperature, the pore former material addition and the strontium content. The largest specific surface area of La 0.2 Sr 0.8 MnO 3 reached 114.3 m 2 /g. Graphical abstract

Improving the Performance of BaMnO3 Perovskite as Soot Oxidation Catalyst Using Carbon Black during Sol-Gel Synthesis

“…This fact highly impacts the intrinsic activity of perovskites and, by increasing the surface area, the performance of some perovskite-like catalysts would be comparable to PGM catalysts. Consequently, a challenging issue in the design of perovskite-like materials with high surface area [9] by different synthesis methods [10][11][12][13][14][15][16][17][18] such as the modified sol-gel synthesis [10], solvothermal methods [11], the synthesis of nanoparticles [9,10,12], and of nanoporous [10,13], mesoporous [14,15] and macroporous [16,17] perovskites. Among others, the nano casting technique allows the increase in the surface area using ordered mesoporous materials, as silica or carbon [9,18].…”

Large Specific Surface Area Macroporous Nanocast LaFe1−xNixO3: A Stable Catalyst for Catalytic Methane Dry Reforming

“…Perovskite-type oxides (PTOs) have shown great potential as precursors for the catalytic reformation of CH 4 and CO 2 [3,15,[25][26][27][28][29][30][31][32][33]. PTO has the general formula ABO 3 , wherein A is usually a La-based ion or a second main-group metal ion and B is usually a transition metal ion.…”

“…Two distinct exothermic peaks could be observed in the DSC profile, which means two types of C are deposited in Ni active sites. e weight loss peak at low temperatures (250-350°C) can be attributed to the oxidation of active C (α-C), which is an active species in the MDR reaction[7,27]. e mass loss of LaFe 0.5 Ni 0.5 O 3 is 1.2%, while that of LaFe 0.3 Ni 0.7 O 3 is very small.…”

Alkali-modified heterogeneous Pd-catalyzed synthesis of acids, amides and esters from aryl halides using formic acid as the CO precursor

“…In many catalytic reactions, catalytic performance is oen ascribed to the physiochemical properties of the catalyst, such as surface areas, pore sizes/volumes. [52][53][54][55][56][57] It is critical to highlight that these features were not overt or considered a determining factor in the moderate to high catalytic activity reported for the nanomaterials in this study. The textural properties of nanoparticles are summarized in Table 1.…”