Pore Structure−Chemical Composition Interactions of New High Surface Area Manganese Based Mesoporous Materials. Materials Preparation, Characterization, and Catalytic Activity

Langmuir ◽  
2002 ◽  
Vol 18 (2) ◽  
pp. 423-432 ◽  
Author(s):  
Constantinos E. Salmas ◽  
Vassilis N. Stathopoulos ◽  
Philippos J. Pomonis ◽  
George P. Androutsopoulos
1999 ◽  
Vol 590 ◽  
Author(s):  
MA Holland ◽  
DM Pickup ◽  
G Mountjoy ◽  
SC Tsang ◽  
GW Wallidge ◽  
...  

ABSTRACTThe synthesis of high surface area (TiO2)0.18(SiO2)0.82xerogels has been achieved using the sol-gel route. Heptane washing was used before the drying stage to minimise capillary pressure and hence preserve pore structure and maximise the surface area. The as-prepared xerogels were tested for their catalytic activity using the epoxidation of cyclohexene with tert-butyl hydrogen peroxide (TBHP) as a test reaction. Surface areas up to 450 m2g-1 were achieved with excellent selectivities and reasonable percent conversions. SAXS data has identified that heptane washing during drying, in general, results in a preservation of the pore structure, and produces more effective catalysts with higher surface areas and larger pore diameters. Fr-IR spectroscopy has revealed that the catalytic activity is dependant upon the number of Si-O-Ti linkages, inferring intimate mixing of the precursors at the atomic level. XANES data reveals the presence of reversible 4/6-fold Ti sites that are thought to be ‘active’ catalytic sites. The most effective catalyst was produced with a calcination temperature of 500°C, and a heating rate of 5 °Cmin-l


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3602 ◽  
Author(s):  
Neel Narayan ◽  
Ashokkumar Meiyazhagan ◽  
Robert Vajtai

Nanoparticles play a significant role in various fields ranging from electronics to composite materials development. Among them, metal nanoparticles have attracted much attention in recent decades due to their high surface area, selectivity, tunable morphologies, and remarkable catalytic activity. In this review, we discuss various possibilities for the synthesis of different metal nanoparticles; specifically, we address some of the green synthesis approaches. In the second part of the paper, we review the catalytic performance of the most commonly used metal nanoparticles and we explore a few roadblocks to the commercialization of the developed metal nanoparticles as efficient catalysts.


2020 ◽  
Vol 8 (35) ◽  
pp. 18318-18326 ◽  
Author(s):  
Hailong Peng ◽  
Yangcenzi Xie ◽  
Zicheng Xie ◽  
Yunfeng Wu ◽  
Wenkun Zhu ◽  
...  

Porous high entropy alloy CrMnFeCoNi exhibited remarkable catalytic activity and stability toward p-nitrophenol hydrogenation. The enhanced catalytic performance not only resulted from the high surface area, but also from exposed high-index facets with terraces.


Author(s):  
Marianna Nassi ◽  
Elena Sarti ◽  
Luisa Pasti ◽  
Annalisa Martucci ◽  
Nicola Marchetti ◽  
...  

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