The polarization work, is traditionally believed to originated from the dipole of a single hoping ion. We showed that such a classical picture does not hold in general. The effect of electric fields on reaction barrier heights can be simplifed to the electric work of a single jumping ion only in the case of subtle symmetry-related compensations and strong ionic character, while in general collective environment effects are present. Our findings will not only impact on theoretical/computational modelling but also on how experimental measures are analyzed.
COBISS.SI-ID: 21507331
Transition-metal (oxy)hydroxides with an abundance of redox metal sites are important for the development of electrochromic devices, rechargeable metal-air batteries, pseudo-capacitors, and industrial electrolyzers. The robust charging reversibility of the redox metal sites ensures long-term durability of the devices but remains unachieved and usually ignored. Here, we use in situ UV-vis and Raman spectroscopies to track the redox states of a nickel hydroxide Nmodel catalyst for the oxygen evolution reaction (OER) during its lifetime in strong alkaline media. Our results suggest that the deactivated and unreduced Ni sites hardly re-hydrate/re-hydroxylate and thus obstruct the OER process. These findings provide direct evidence for elucidation of the origin of the oxygen evolution decay and contribute to a reference to extend the lifetime of the catalysts by stabilizing the reversible redox metal sites.
COBISS.SI-ID: 25099011
We reported a combined microscopy and spectroscopy study of Au deposited on the Bi2Se3(0001) single crystal surface. At room temperature Au forms islands, according to the Volmer-Weber growth mode. Upon annealing to 100° C the Au deposits are not stable and assemble into larger and thicker islands. The topological surface state of Bi2Se3 is weakly affected by the presence of Au. Contrary to other metals, such as Ag or Cr, a strong chemical instability at the Au/Bi2Se3 interface is ruled out. Core level analysis highlights Bi diffusion toward the surface of Au islands, while chemical interaction between Au and atomic Se is limited at the interfacial region.
COBISS.SI-ID: 5276923
This work presents a flowsheet superstructure and integration possibilities for simultaneous optimization of the maximum share of attainable direct and indirect solar utilization through heat storage in industrial operations. Multi-period Mixed Integer Non-Linear Programming (MINLP) models were developed for this purpose and account for the dynamics in the profile of heat supply and demand using discrete time intervals/periods. The resulting models are applied to an industrial case study of a dairy plant for the two distinct integration alternatives of targeting one and multiple (two) cold stream utility requirements. The design and optimization of the integrated system is implemented and solved in GAMS. The results show good prospect for solar thermal utilization in industries with low temperature applications. Sensitivity analysis shows linear increase in the average attainable heat load up to certain collector area (on case-by-case basis), after which a break point is obtained where it is observed that additional increase in collector area does not result to much increase in the obtained heat load. For the selected case study of a dairy plant, average solar output of about 75?W/m2 of collector is obtained.
COBISS.SI-ID: 22407190
We reported on a hydrothermal synthesis of hexagonal ultra-thin Bi2Se3 platelets, which was performed without any organic reactants. The synthesis resulted in the particles with a surface, clean of any organic adsorbents. Due to the absence of the adsorbed organic layer on the Bi2Se3 platelet surface, we were able to measure their inherent surface and optical properties.The surface of the hydrothermally synthesized Bi2Se3 platelets was so clean to enable the occurrence of the localized surface plasmon resonance due to the topological surface electronic states.
COBISS.SI-ID: 5506299