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The purpose of this study is to apply the distribution function formalism to the problem of electronic transport in open systems, and to numerically solve the kinetic equation with a dissipation term. This term is modeled within the relaxation time approximation and contains two parts, corresponding to elastic or inelastic processes. The collision operator is approximated as a sum of the semi-classical energy dissipation term and the momentum relaxation term, which randomizes the momentum but does not change the energy. As a result, the distribution of charge carriers changes due to the dissipation processes, which has a profound impact on the electronic transport through the simulated region discussed in terms of the current–voltage characteristics and their modification caused by the scattering. Measurements of the current–voltage characteristics for titanium dioxide thin layers are also presented, and compared with the results of numerical calculations.

The multi-component approach to materials design is gaining increasing popularity in energy-conversion-oriented applications. This study describes a 5-component multimetallic chalcogenide compound with a pentlandite structure that recently became increasingly interesting in terms of electrocatalytic water splitting. The solubility limit of Se in the trimetallic Co3Fe3Ni3S8 system was determined along with the potential effect of this additive on the material's intrinsic properties. This was followed by an unprecedented approach, an attempt to fabricate solid electrodes using the inductive hot-pressing method. The effects of the consolidation conditions on the morphology and final properties of the material are discussed in detail. Tailoring both the chemical composition and processing conditions (initial grain size, sintering temperature) can lead to the optimization of highly efficient electrocatalysts for water splitting. The best electrodes were characterized at elevated current densities of 120 mA cm−2, showing low overpotentials (240 mV versus RHE) but with rather low electrochemical active surface area and moderately optimal reaction kinetics. It was therefore shown that using multi-component compositions resulted in good intrinsic properties of the materials toward hydrogen production, together with high density and vacancy concentrations provided by the sintering process, thus producing an efficient electrocatalyst using a simple, scalable method without any additional processing. [ABSTRACT FROM AUTHOR]

Flower-like TiO2 nanostructures were obtained by chemical oxidation of Ti foil using H2O2 combined with subsequent annealing. This paper offers an analysis of the phase transformation of 3D flower-like titanium dioxide nanostructures. The role of the annealing atmosphere, sample thickness, grain shape, and nanoflower size are discussed. The nanostructures were examined using SEM, XRD, and Raman spectroscopy. Due to the nature of these two processes, the morphology of these nanomaterials is complex, and is obtained through a reaction involving Ti foil and H2O2 at 80°C. A distinction is made between the layer composed of small grains at the substrate/oxide interface, elongated crystal-like structures, and outer spongle-like film. The annealing parameters, such as atmosphere (air or argon) and temperature (450 or 600 °C), affect phase composition. The photoelectrochemical performance of the anode based on flower-like TiO2 has been shown. The thickness and phase composition of the anodes are factors that strongly affect the photocurrent. The multiphase heterojunctions proposed for 3D flower-like TiO2 photoanodes in photoelectrochemical (PEC) cells suppose that the conduction band of anatase should be above rutile. The highest photoelectrochemical performance was obtained for a photoanode composed of 20–40% anatase and an associated thickness of 0.75–1.5 µm. [ABSTRACT FROM AUTHOR]