Publications by authors named "Nikos Liakakos"
Cobalt is an efficient catalyst for Fischer-Tropsch synthesis (FTS) of hydrocarbons from syngas (CO + H) with enhanced selectivity for long-chain hydrocarbons when promoted by Manganese. However, the molecular scale origin of the enhancement remains unclear. Here we present an experimental and theoretical study using model catalysts consisting of crystalline CoMnO nanoparticles and thin films, where Co and Mn are mixed at the sub-nm scale.
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- * Cobalt nanorods were created by reducing a Co(II) precursor in the presence of specific chemicals, and additional studies were conducted to observe the growth process over time.
- * Results indicate that the formation involves a combination of fast and slow processes, leading to organized structures known as mesocrystals, with orderly alignment occurring early in the growth phase.
Article Synopsis
- APXPS and HPSTM techniques were employed to investigate Cu(100) and Cu(111) catalyst surfaces during CO2 interaction, revealing that the (100) surface is more effective at dissociating CO2.
- Dissociated atomic oxygen hinders further CO2 adsorption by blocking the surface, contributing to a "self-poisoning" effect that necessitates the addition of CO in industrial methanol production to mitigate this issue.
- Under high CO2 pressure (20 Torr), the (100) surface forms nanoclusters that enhance active sites; however, if atomic oxygen is already present, this clustering does not occur.
Article Synopsis
- The study focuses on creating and analyzing hybrid nanostructures made of iron (Fe) nanocubes bonded to cobalt (Co) nanorods, highlighting their unique shapes and magnetic properties.
- Advanced electron microscopy techniques, including high-resolution transmission electron microscopy (HRTEM), electron tomography, and EDX tomography, were used to understand their structure and composition.
- The iron nanocubes serve as nucleation centers that significantly alter the magnetization behavior of the entire hybrid structure, enhancing the overall magnetic anisotropy.
The control of nanocrystal structures at will is still a challenge, despite the recent progress of colloidal synthetic procedures. It is common knowledge that even small modifications of the reaction parameters during synthesis can alter the characteristics of the resulting nano-objects. In this work we report an unexpected factor which determines the structure of cobalt nanoparticles.
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