Search the repository

A+ | A- | | SLO | ENG

Abstract: Functional materials play a pivotal role in enhancing the efficiency and performance of electrocatalytic systems. These materials exhibit unique characteristics that facilitate electrochemical reactions, such as the reduction of carbon dioxide (CO2), the splitting of water or the oxidation of organics, crucial for energy conversion applications. Understanding the fundamental principles governing the behavior of functional materials in electrocatalytic processes is essential for advancing this field. The correlation between material properties, such as composition, morphology, and surface structure, and their electrocatalytic performance are essential puzzle to design functional materials. During this presentation, I will provide an overview of many potential technologies and concepts utilized in energy conversion. My presentation will center on the electrocatalytic oxidation of organic compounds, CO2 reduction and water electrolysis. I will discuss the utilization of MoSe2, WC, Fe2P, FeP, WO3, and Fe2O3 in water electrolysis. I will highlight effective solutions for CO2 electroreduction in high-pressure environments and with the use of flow cells. Electrooxidation of biomass will be discussed as a potential match for CO2 reduction and H2 production. Seeking effective materials for electrocatalytic energy conversion is a crucial aspect of the search for sustainable and clean energy solutions. Finally, a techno-economic analysis shall be overviewed to assess the economic viability and competitiveness of CO2 electrolysis as a carbon capture and utilization technology.
Keywords: CO2 reduction, functional materials, electrochemistry
Published in RUNG: 07.01.2025; Views: 667; Downloads: 2
Link to file
This document has many files! More...

Abstract: We present a combined study based on the experimental measurements of an infrared (IR) dielectric function and first-principles calculations of IR spectra and the vibrational density of states (VDOS) of amorphous alumina (am−Al2O3). In particular, we show that the main features of the imaginary part of the dielectric function ε2(ω) at ∼380 and 630 cm−1 are related to the motions of threefold-coordinated oxygen atoms, which are the vast majority of oxygen atoms in am-Al2O3. Our analysis provides an alternative point of view with respect to an earlier suggested assignment of the vibrational modes, which relates them to the stretching and bending vibrational modes of AlOn (n=4, 5, and 6) polyhedra. Our assignment is based on the additive decomposition of the VDOS and ε2(ω) spectra, which shows that (i) the band at ∼380cm−1 features oxygen motions occurring in a direction normal to the plane defined by the three nearest-neighbor aluminum atoms, i.e., out-of-plane motions of oxygen atoms; (ii) Al-O stretching vibrations (i.e., in-plane motions of oxygen atoms) appear at frequencies above ∼500cm−1, which characterize the vibrational modes underlying the band at ∼630cm−1. Aluminum and fourfold-coordinated oxygen atoms contribute uniformly to the VDOS and ε2(ω) spectra in the frequency region ∼350–650 cm−1 without causing specific features. Our numerical results are in good agreement with the previous and presently obtained experimental data on the IR dielectric function of am−Al2O3 films. Finally, we show that the IR spectrum can be modeled successfully by assuming isotropic Born charges for aluminum atoms and fourfold-coordinated oxygen atoms, while requiring the use of three parameters, defined in a local reference frame, for the anisotropic Born charges of threefold-coordinated oxygen atoms.
Keywords: dielectric properties, microstructure, amorphous materials, density functional calculations, infrared techniques, aluminium oxide
Published in RUNG: 10.05.2023; Views: 2911; Downloads: 12
Link to full text
This document has many files! More...