نتایج جستجو برای: hybrid catalysts
تعداد نتایج: 223194 فیلتر نتایج به سال:
In this study, the nanoporous γ-alumina catalysts were prepared by the sol-gel method using hydrolysis of aluminum isopropoxide in the presence of TX-100 or gelatin/TX-100 mixture. Catalysts were characterized by XRD, FT-IR, TEM, BET-BJH and N2 adsorption-desorption isotherms. To investigate reactivity and selectivity of the synthesized catalysts, dehydration reaction of 2-octanol was carried o...
Received: 15 December 2004; Revised: 26 January 2005 Abstract Copper zinc oxide catalysts prepared similar to industrially used catalysts were studied by high-resolution electron microscopy. The microstructure of the Cu/ZnO catalysts deviates considerably from that of bulk copper metal and idealized copper model systems. In order to reveal reliable structure-activity relationships for copper ca...
Copper-manganese oxide catalysts are prepared with an atomic ratio of Cu/Mn=2/1 using a coprecipitation procedure under air atmosphere. The time of aging, i.e., the time that precipitate remains in contact with the precipitating medium, has been varied from 0 (for unaged precursor) to 300 minutes and the effect of precipitate aging time in each atmosphere upon the structure and morphology of di...
Using MeN=CMe(2) as an imine model, computational chemistry has been applied to design metal-free hydrogenation catalysts. The implementation includes designing proper electronic structures to split H(2) and building appropriate chemical scaffolds to prevent possible side reactions which may deactivate the catalysts. Interestingly, the designed catalysts bear resemblances to the well-known meta...
Atomically dispersed catalysts refer to substrate-supported heterogeneous catalysts featuring one or a few active metal atoms that are separated from one another. They represent an important class of materials ranging from single-atom catalysts (SACs) and nanoparticles (NPs). While SACs and NPs have been extensively reported, catalysts featuring a few atoms with well-defined structures are poor...
In contrast to solid acid catalysts, much fewer efforts have been made to study solid base catalysts. In this thesis, preparation, characterization and application of oxides and modified oxide as solid base catalysts were studied. The catalysts include MgO prepared by different methods, potassium-modified ZrO2, calcined Mg-Al hydrotalcites, and a novel catalyst system Mg(O,F), which was prepare...
the series of mono-metallic and bi-metallic catalysts have been prepared by impregnatingwith solutions containing compound of h2ptc15,nbc15 and lml hc1 (0.1 mol). the activityand selectivity of the catalysts have been determined under conditions at 450-500°c, 15-30atm. molar ratio h2/c7h16=5 and vvh=1.5/h for converting n-heptane. under theseexperimental conditions it has been established that ...
The future of analytical devices, namely (bio)sensors, which are currently impacting our everyday life, relies on several metrics such as low cost, high sensitivity, good selectivity, rapid response, real-time monitoring, high-throughput, easy-to-make and easy-to-handle properties. Fortunately, they can be readily fulfilled by electrochemical methods. For decades, electrochemical sensors and bi...
Both structural and compositional modulations are important for high-performance electrode materials in energy conversion/storage devices. Here hierarchical-structure nitrogen-rich hybrid porous carbon capsules with bamboo-like carbon nanotube whiskers (N-CC@CNTs) grown in situ have been specifically designed, which combine the advantageous features of high surface area, abundant active sites, ...
According to this electronic model, the transition state (TS) is stabilized by donor–acceptor orbital interactions from metal d orbitals to the substrate s*C X, which become more stabilizing as the metal–ligand d hybrid orbital is pushed up at smaller bite angles. Here, we provide evidence that the mechanism through which the bite angle affects barrier heights (and also the twist angle in the T...
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