Characterization and catalytic reactivity of xerogel catalysts based on mesoporous zirconia doped with telluric acid prepared by sol–gel method: mechanistic study of acetic acid esterification with benzyl alcohol

Author(s):  
Wafa Ksila ◽  
Mohamed Kadri Younes ◽  
Abdelhamid Ghorbel ◽  
Alain Rives
2011 ◽  
Vol 170 (2-3) ◽  
pp. 518-524 ◽  
Author(s):  
Yongjun Chen ◽  
Suzanne K. Lunsford ◽  
Yongcheng Song ◽  
Huangxian Ju ◽  
Polycarpos Falaras ◽  
...  

2011 ◽  
Vol 364 ◽  
pp. 412-416 ◽  
Author(s):  
Mohammad Hafizuddin Haji Jumali ◽  
Mariam Mohamad Siti ◽  
Rozidawati Awang ◽  
Muhammad Yahaya ◽  
Muhamad Mat Salleh

The effects of annealing temperatures on nanostructure of Na0.5Bi0.5TiO3(NBT) ceramics prepared by sol gel method were investigated. Sol of NBT were synthesized using raw materials namely NaCH3COO, C6H9BiO6and Ti (C4H9)4, while 2-methoxyethanol and glacial acetic acid were used as solvents. The sol of NBT was dried at 100°C for 24 hours, ground and subsequently annealed at three different temperatures namely 500°C, 600°C and 700°C for 2 hours. Microstructure and morphology of the ceramics were examined using XRD and SEM respectively. XRD revealed that the sample annealed at 500°C contains transient pyrocholore phase while materials annealed at higher temperatures has NBT as primary crystalline phase. The crystallite size dramatically increased from 10 nm to 80 nm with the rise of annealing temperatures. SEM micrographs confirmed the presence of irregular NBT nanoparticles with sizes of 50.0 nm and 80.0 nm for samples annealed at 600°C and 700°C respectively.


2012 ◽  
Vol 501 ◽  
pp. 76-80
Author(s):  
Mohammad Hafizuddin Haji Jumali ◽  
Siti Mariam Mohamad ◽  
Rozidawati Awang ◽  
Muhammad Yahaya ◽  
Mohd Riduan M. Said ◽  
...  

The effect of annealing temperatures on the formation of pure perovskite Na0.5Bi0.5TiO3 (NBT) based ceramics prepared by sol gel method has been investigated. The NBT sol was prepared using NaCH3COO, C6H9BiO6 and Ti(C4H9)4 with 2-methoxyethanol and glacial acetic acid were used as solvents. The BaTiO3 sol was synthesized using C4H6BaO4 and Ti(C4H9)4 with acetic acid and ethanolamine were used as solvents. The (Na0.5Bi0.5)0.96Ba0.04TiO3 (NBBT) sol was prepared by mixing appropriate amount of NBT and BaTiO3 sols. Then NBT and NBBT sols were dried at 200oC for 24 h, ground and subsequently annealed at temperatures ranging from 440oC – 640oC for 5 min. Formation of NBT and NBBT ceramics was examined using XRD technique. X-ray diffractograms reveal that the NBT ceramic with rhombohedral structure starts to form at 540oC and complete crystallization is achieved at 620oC. Addition of 4vol% of BaTiO3 sols drastically reduces the crystallization temperature of NBBT ceramic to 460oC and a pure single phase ceramic is achieved at 520oC. Despite retaining the same rhombohedral structure, the NBBT exhibits lattice parameters expansion indicating a successful Ba substitution which is also confirms by the absence of BaTiO3 peaks in the diffractograms. Both ceramics exhibit great thermal stability with additional increment in annealing temperatures.


2018 ◽  
Vol 8 (12) ◽  
pp. 3166-3173 ◽  
Author(s):  
Qilei Yang ◽  
Dong Wang ◽  
Chizhong Wang ◽  
Xianfeng Li ◽  
Kezhi Li ◽  
...  

LaCoO3 (LCO-0) perovskite catalysts were synthesized by the traditional citrate sol-gel method for toluene oxidation. The catalytic activity of the modified LaCoO3 (LCO-1) by acetic acid significantly increased.


2019 ◽  
Vol 30 (10) ◽  
pp. 9194-9199
Author(s):  
Yan Cui ◽  
Wang Gu ◽  
Xiangxin Kong ◽  
Zhidong Gao ◽  
Shunyao Yu

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