Synthesis and characterization of visible-light-driven novel CuTa2O6 as a promising practical photocatalyst

In this work, the novel CuTa2O6 phase was successfully synthesized by the hydrothermal and followed by the calcination process. The X-ray diffraction pattern confirms the formation of different phases. At a low temperature, CuTa2O6 exhibits the orthorhombic phase, whereas, at a higher temperature, it underwent a phase transition to a cubic crystal structure. X-ray photoelectron spectroscopic results suggest the presence of all the elements (Cu, Ta, and O). The optical studies were carried out using a UV-Vis DRS spectrophotometer. FESEM images confirm the spherical-shaped particles for the sample annealed at a high temperature. The local atomic and electronic structures around Cu and the contribution of the Cu oxidation state in the CuTa2O6 system were determined by X-ray absorption spectroscopy. To investigate the effective usage of CuTa2O6 in treating wastewater, its photocatalytic activity was investigated by evaluating its use in the photodegradation of MO dye under visible light irradiation. Moreover, the prepared CuTa2O6 photocatalyst exhibits significant photocatalytic activity in the degradation of MO dye and shows excellent stability; it is therefore a promising material for potential use in a practical photocatalyst. The CuTa2O6 photocatalyst suggests an alternative avenue of research into effective photo-catalysts for solar hydrogen water splitting

Enhancement of thermoelectric performance of n-type In2(Te0.94Se0.06)3 thin films by electronic excitations

[[abstract]]Thermoelectric properties of metal chalcogenide based materials exhibit a great suitability in the field of energy sustainability. This study reports the thermoelectric properties of In2(Te0.94Se0.06)3films prepared by thermal evaporation before and after the electronic excitations produced by 120 MeV Au ions. The Seebeck coefficient value for pristine sample is found to be ~196 µV K−1 and it is enhanced to ~347 µV K−1 at the higher fluence of 1 × 1013 ions/cm2 at 400 K. The negative value of Seebeck coefficient and the Hall effect measurements confirm the n-type conductivity in the pristine and irradiated samples. The power factor value of thin films irradiated at the fluence of 1 × 1013 ions/cm2 is ~3.80 μW/K2 m, as compared to pristine sample ~1.28 μW/K2 m. The change in image contrast in FESEM is due to grain fragmentation with increase in ion fluence in comparison to the pristine sample. It is evident that the electrical resistivity and power factor values are higher for irradiated samples as compared to that of pristine samples. Moreover, presence of high density of nanoscale grain boundaries created by ion irradiations lead to the enhancement in thermoelectric properties of In2(Te0.94Se0.06)3 thin films.[[notice]]補正完

Structural and thermoelectric properties of Se doped In2Te3 thin films

The Se-Te based chalcogenides exhibit novel property of Phase Change Memory (PCM) which has potential applications in electrical non-volatile memories. These materials are also suitable in thermal to electrical energy conversions and, hence, of potential interest in energy sustainability as thermoelectric devices. In this study, the Se doped In2Te3 thin films were prepared by thermal evaporation and were annealed at 250 °C and 300 °C in Argon gas. The X-ray diffraction spectra show that thermal annealing leads to the phase transitions in Se doped In2Te3 into binary phases of In2Se3 and In2Te3. The surface morphology of the films exhibits the grains of spherical nature. Annealing also decreases the energy band gap due to the presence of two phases. From the four probe and photoconductivity measurements, a large contrast in electrical resistance between the amorphous and crystalline states is found with a variation of a few orders of magnitude. The electrical transport properties such as the electrical resistivity, Seebeck coefficient and the power factor were measured in the temperature range from 300 K to 430 K. All the deposited and annealed thin films exhibit n-type conductivity with the Seebeck coefficient ranging from -338 μVK-1 to -510 μVK-1. An increase in thermoelectric power of 25% is observed in the 300 °C annealed films in comparison to the as-deposited films. Moreover, the lower Se doped In2(Te0.96Se0.04)3 compound exhibits a better thermoelectric performance compared to the In2(Te0.90Se0.1)3 composition. This study shows the multifunctional nature of Se doped In2Te3 both for PCM and thermoelectric applications

Effects of Heavy Ion Irradiation on the Thermoelectric Properties of In₂(Te_1−xSe_x)₃ Thin Films

Ion irradiation is an exceptionally effective approach to induce controlled surface modification/defects in semiconducting thin films. In this investigation, ion-irradiated Se–Te-based compounds exhibit electrical transport properties that greatly favor the transformation of waste heat into electricity. Enhancements of both the Seebeck coefficient (S) and the power factor (PF) of In2(Te0.98Se0.02)3 films under 120 MeV Ni9+ ion irradiation were examined. The maximum S value of the pristine film was about ~221 µVK−1. A significantly higher S value of about ~427 µVK−1 was obtained following irradiation at 1 × 1013 ions/cm2. The observed S values suggest the n-type conductivity of these films, in agreement with Hall measurements. Additionally, Ni ion irradiation increased the PF from ~1.23 to 4.91 µW/K2m, demonstrating that the irradiated films outperformed the pristine samples. This enhancement in the TE performance of the In2(Te0.98Se0.02)3 system is elucidated by irradiation-induced effects that are revealed by structural and morphological studies

Trimetallic Oxide Electrocatalyst for Enhanced Redox Activity in Zinc–Air Batteries Evaluated by In Situ Analysis

Abstract Researchers are investigating innovative composite materials for renewable energy and energy storage systems. The major goals of this studies are i) to develop a low‐cost and stable trimetallic oxide catalyst and ii) to change the electrical environment of the active sites through site‐selective Mo substitution. The effect of Mo on NiCoMoO4 is elucidated using both in situ X‐ray absorption spectroscopy and X‐ray diffraction analysis. Also, density functional theory strategies show that NiCoMoO4 has extraordinary catalytic redox activity because of the high adsorption energy of the Mo atom on the active crystal plane. Further, it is demonstrated that hierarchical nanoflower structures of NiCoMoO4 on reduced graphene oxide can be employed as a powerful bifunctional electrocatalyst for oxygen reduction/evolution reactions in alkaline solutions, providing a small overpotential difference of 0.75 V. Also, Zn–air batteries based on the developed bifunctional electrocatalyst exhibit outstanding cycling stability and a high‐power density of 125.1 mW cm−2. This work encourages the use of Zn–air batteries in practical applications and provides an interesting concept for designing a bifunctional electrocatalyst