Publications by authors named "Elias Frei"

Developing high-performance Fe-based ammonia catalysts through simple and cost-efficient methods has received an increased level of attention. Herein, we report for the first time, the synthesis of two-dimensional (2D) FeOOH nanoflakes encapsulated by mesoporous SiO (mSiO) via a simple solution-based method for ammonia synthesis. Due to the sticking of the mSiO coating layers and the limited spaces in between, the Fe after reduction retains the 2D morphology, showing high resistance against the sintering in the harsh Haber-Bosch process.

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A systematic variation of the SBA-15 synthesis conditions and their impact on the structural and chemical characteristics are reported. An incremental alteration of the hydrothermal aging temperature and time was used to induce changes of the highly ordered SBA-15 structure. Any effects on the total surface area, mesopores size, micropore contributions, and pore connectivity are amplified by a combined incremental increase of the NH F concentration.

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Polycrystalline ZnO is a material often used in heterogeneous catalysis. Its properties can be altered by the addition of dopants. We used gaseous fluorine (F) as direct way to incorporate fluoride in ZnO as anionic dopants.

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The influence of a mild difluorine treatment on Cu/ZnO precatalysts for methanol synthesis was investigated. It led to the incorporation of 1.2…1.

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We report on the activation of CO on Ni single-atom catalysts. These catalysts were synthesized using a solid solution approach by controlled substitution of 1-10 atom % of Mg by Ni inside the MgO structure. The Ni atoms are preferentially located on the surface of the MgO and, as predicted by hybrid-functional calculations, favor low-coordinated sites.

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The existence of a limited solid-solution series in the Cu/Zn binary metal oxalate system is reported. Coprecipitation was applied for the preparation of a comprehensive set of mixed Cu/Zn oxalates. Rietveld refinement of the XRD data revealed the formation of mixed-metal oxalate single phases at the compositional peripheries.

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The electrodeposition nature of copper on a gold electrode in a 4.8 pH CuSO solution was inquired using X-ray absorption spectroscopy, electrochemical quartz crystal microbalance, and thermal desorption spectroscopy techniques. Our results point out that the electrodeposition of copper prompts the formation of stable oxi-hydroxide species with a formal oxidation state Cu without the evidence of metallic copper formation (Cu).

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Long-term stability of catalysts is an important factor in the chemical industry. This factor is often underestimated in academic testing methods, which may lead to a time gap in the field of catalytic research. The deactivation behavior of an industrially relevant Cu/ZnO/Al2 O3 catalyst for the synthesis of methanol is reported over a period of 148 days time-on-stream (TOS).

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Catalytically synthesized methanol from H2 and CO2 using porous Cu/ZnO aggregates is a promising, carbon neutral, and renewable alternative to replace fossil fuel based transport fuels. However, the absence of surface-engineered model systems to understand and improve the industrial Cu/ZnO catalyst poses a big technological gap in efforts to increase industrial methanol conversion efficiency. In this work, we report a novel process for the fabrication of patterned, vertically aligned high aspect ratio 1D nanostructures on Si that can be used as an engineered model catalyst.

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