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Time-dependent DFT and experimental study on visible light photocatalysis by metal oxides of Ti, V and Zn after complexing with a conjugated polymer
摘要： Density Functional Theory (DFT) and Time Dependent (TD)-DFT studies predict substantial modifications in optical properties of Transition Metal Oxides (TMOs) of Ti, V and Zn by complexing them with conjugated polymer polythiophene (PTh). The TMO nanostructures were synthesized and their complexes with polymers were fabricated using a chemical oxidative polymerization method. Coating of the TMOs with PTh and the nano-dimensional nature of the samples was confirmed by various morphological investigations such as infrared (IR), X-ray di?ractographs (XRD), High Resolution Transmission Electron Microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM) techniques. The prepared samples were found to be a visible light driven photocatalyst. The sensitization of the complexes has been explained in terms of relative ordering of frontier orbitals of PTh and the TMO, and PTh qualified as an e?cient photosensitizer for all three metal oxides on the basis of its electronic characteristics. Since the Highest Occupied Molecular Orbital (HOMO) of PTh lies well between the band gap of all three TMOs, the electron transfer from donor (PTh) to acceptor (TMO) is facilitated. The appreciable red shift in the absorption spectrum and decrease in the optical band gap calculated by Tauc’s plot confirmed substantial reduction in the band gap of the formed complex in comparison to their bare counterparts. The isodensity plots established the PTh–TMO complexes as donor acceptor complexes and intermolecular charge transfer quantified the electron transfer from PTh (donor) to the TMOs (acceptor).
关键词： conjugated polymer,TD-DFT,visible light,metal oxides,DFT,photocatalysis,polythiophene,band gap tuning
更新于2025-11-14 17:04:02
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Functionalization of the transition metal oxides FeO, CoO, and NiO with alkali metal atoms decreases their ionization potentials by 3–5 eV
摘要： The existence and stabilities of various neutral metal oxides of formula MON and MON2 (M = Fe, Co, Ni; N = Li, Na) and their corresponding cations MON+ and MON2+ are predicted using density functional theory (B3LYP) with the 6-311 + G(d) basis set. Ab initio calculations carried out at the CCSD(T)/6-311 + G(3df) level of theory reveal that the ionization potentials (IPs) of the oxides MO decrease by ca. 3–5 eV upon functionalization with N to give either MON or MON2. The influences of the chemical constitution and local spin magnetic moment (on the transition metal atom) of the oxide or cation on its IP are presented and discussed.
关键词： Transition metal oxides,Strong reducers,Mixed oxides,Superalkalis
更新于2025-09-23 15:23:52
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Fe doping effect of vanadium oxide films for enhanced switching electrochromic performances
摘要： In the present study, Fe-doped V2O5 films showing impressive electrochromic (EC) performance were developed using the sol-gel spin-coating method. To confirm the optimized Fe-doping effect on the V2O5 films for the EC performance, we adjusted the Fe atomic percentages to 0.0, 0.5, 1.0, and 1.5 at%, respectively. With the effect of Fe doping on the V2O5 films, the obtained films resulted in the formation of the oxygen vacancies. As the result, when the optimum Fe atomic percentage was 1.0 at%, the enhanced switching speeds (3.7 s for the bleaching speed and 2.0 s for the coloration speed) and enhanced coloration efficiency value (47.3 cm2/C) compared to the other films were implemented. This can be attributed to the improved electrical conductivity and Li+ diffusion coefficient that led to efficient generation of the EC reaction activity and narrowing the optical bandgap at the coloration state to increase transmittance modulation. Therefore, this unique film can be a promising EC material to improve the performance for the EC devices.
关键词： Films,Optical properties,Transition metal oxides,Electrical properties,Electrochromic performances
更新于2025-09-23 15:23:52
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Atomic layer deposition of hybrid metal oxides on carbon nanotube membranes for photodegradation of dyes
摘要： Synthetic dye pollution is a worldwide problem and quick remedies are urgently needed. Photocatalysis is a promising method to solve this problem and carbon nanotubes (CNTs) are promising components in producing high-performance composite photocatalysts. Nevertheless, the strong hydrophobicity dramatically impedes its application in aqueous environments. In this study, hydrophilic CNT-hybrid metal oxides (ZnO and TiO2) membranes were prepared by atomic layer deposition (ALD). We demonstrate that ALD is an efficient and flexible method to enhance the photocatalytic activity of CNT-based membranes, especially the membranes used in wastewater treatments. The hybrid hexagonal wurtzite ZnO and anatase TiO2 on CNTs after calcination could effectively enhance electron transfer and reduce photo-generated electron-holes recombination. The membranes exhibit preferable photocatalytic activity and stable reusability in dye degradation. This strategy of "ALD on CNTs" is expected to create other CNT-based membranes with additional functionalities and has bright prospect for wastewater treatments.
关键词： Carbon nanotubes,Photocatalytic degradation,Hybrid metal oxides,Atomic layer deposition
更新于2025-09-23 15:23:52
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Electrochemical properties of PEDOT: PSS /V2O5 hybrid fiber based supercapacitors
摘要： Binary conducting polymer (CP)/transition metal oxides (TMOs) fiber-based supercapacitors (FSCs) are considered to possess good electrochemical performance and cyclic stability compared with unitary ones since TMOs within FSCs can prevent the structure damage of CP during charge/discharge cycles to some extent. In this study, the CP/TMOs hybrid fibers are made by directly injecting the solution into capillary. Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate /30 wt% vanadium pentoxide (PEDOT: PSS/30 wt% V2O5) fiber-based electrode has good electrochemical performance and cyclic stability (cycle retention: 94.02% after 4000 cycles at 0.1 mA/cm2). The energy density of the PEDOT: PSS/30 wt% V2O5 fiber in gel electrolyte is 1.37 μWh/cm2 at power density of 20 μW/cm2, which is much lower than the one in organic electrolyte (21.46 μWh/cm2 at power densities of 162.5 μW/cm2). Therefore, the method developed in this work induces good electrochemical performance for hybrid FSCs and promotes scalable fabrication of FSCs.
关键词： transition metal oxides,supercapacitor,Conducting polymers,electrochemical performance,hybrid fiber
更新于2025-09-23 15:23:52
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Facile synthesis of N/B double-doped Mn <sub/>2</sub> O <sub/>3</sub> and WO <sub/>3</sub> nanoparticles for dye degradation under visible light
摘要： In the present work, Nitrogen-doped and Nitrogen-Boron double doped manganese oxide (Mn2O3) and tungsten oxide (WO3) nanoparticles were synthesized using precipitation-hydrothermal method for methylene blue degradation under visible light. Materials were characterized using X-ray diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and UV-Vis spectroscopy. Results showed that N and B were successfully incorporated into the crystal lattices of Mn2O3 and WO3. XRD showed that WO3 was crystallized in the form of a monoclinic lattice, while cubic Mn2O3 was produced in the cubic form. The crystallite size was found to be decreased due to the substitution of N and B elements which reveals their roles to accelerate the crystal nucleation rate resulting in the decreased size. On the other hand, single and double doping has successfully narrowed the bandgaps of the as-synthesised metal oxide photocatalysts resulting in better absorption in the visible light. Bandgaps obtained were as follows: 3.02, 2.50, 1.73 and 1.77 eV for N-WO3 N/B-WO3, N-Mn2O3 and N/B-Mn2O3 respectively. Photocatalytic experiments showed that all as-synthesised materials exhibited a photocatalytic efficiency under visible light ≥420 nm. The degradation efficiency of MB was in the following order: N-B-co-doped metal oxides > N-doped metal oxides > metal oxides. The presence of scavenger molecules such as isopropanol (IPA), EDTA-2Na and benzoquinone inhibited MB degradation. Finally, the results showed that these materials can be reused several times without a notable decrease in efficiency.
关键词： Photocatalytic degradation,Visible light,Double-doping,Metal oxides
更新于2025-09-23 15:23:52
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Sol-gel assisted nano-structured SnO<sub>2</sub> sensor for low concentration ammonia detection at room temperature
摘要： Sol-gel assisted nano-structured SnO2 sensor for low concentration ammonia detection at room temperature. Upon exposure to 500 ppb and 1 ppm of NH3, sensor manifests appreciable response ~ 28 % and ~ 31.5 %, respectively. High response of the sensor at RT is attributed due to porous nanograins (with average particle size ~ 50 nm) based SnO2 thin film layer. Nanograins structure is obtained due to addition of glycerine in the sol solution, which also leads to porosity enhancement of the sensing layer. Good reproducibility and appreciable immunity to drift behavior are other attributes of the fabricated device. High response and good selectivity towards ammonia are observed with very fast response and recovery time at RT, for extreme low concentrations level ~ 55 % RH for concentration range 500 ppb-500 ppm. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) results are used to study the structural, chemical composition, topography and morphological characteristics of the prepared SnO2 thin film, respectively.
关键词： Sol-gel,Room temperature,Ammonia sensor,Metal oxides,% Response,Nanostructured
更新于2025-09-23 15:23:52
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Fabrication of oxidized graphite supported La2O3/ZrO2 nanocomposite for the photoremediation of toxic fast green dye
摘要： The dyes are one of major pollutants discharged to water bodies without any premeditation. Their undesirable detection in aqueous bodies has created a menace as they tend to disturb the complete aquatic ecosystem by directly hindering the photosynthetic process of aquatic flora. Thus pre and post discharge remediation of these dyes are of immense significance. In the present study, novel OG/La2O3/ZrO2 nanocomposite having high photocatalytic ability was prepared by co-precipitation method. Visible photocatalytic ability of the nanocomposite was employed for the degradation of fast green dye as a target pollutant. The OG/La2O3/ZrO2 nanocomposite was well characterized using various techniques as FTIR, XRD, SEM, TEM and XPS etc. The nanocomposite also exhibited adsorption capability due to the presence of oxidized graphite (OG) sheets those provided high surface area for the fast green molecules to get adsorb onto them. High degradation efficiency (89%) was obtained within 90 minutes of visible light irradiation. Effect of pH, photocatalyst amount and light intensity was also studied. Superoxide and hydroxyl radicals; were found to be the major reacting species as confirmed by the scavenging studies. Furthermore, OG/La2O3/ZrO2 nanocomposite exhibited high reusability interpreting the nanocomposite as a proficient photocatalyst with active utilization for treating industrial waste water.
关键词： Fast green dye,Metal- oxides,Oxidized graphite,Photo-degradation
更新于2025-09-23 15:23:52
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Photoelectrochemical water splitting with p-type metal oxide semiconductor photocathodes Youn Jeong Jang[a] and Jae Sung Lee*[a]
摘要： Photoelectrochemical (PEC) water splitting is a promising way to produce clean and sustainable hydrogen fuel. Solar hydrogen production using p-type metal oxide semiconductor photocathodes has not been studied as extensively as n-type metal oxide semiconductor photoanodes and p-type PV-grade non-oxide semiconductor photocathodes. Copper-based oxide photocathodes show relatively good conductivity but suffer from instability in an aqueous solution under illumination. On the other hands, Fe-based metal oxide photocathodes demonstrate more stable PEC performance, but have problems in charge separation and transport. In this mini-review article, we provide an overview of the recent progress in p-type metal oxide-based photocathodes for PEC water reduction. Although these materials are not fully developed up to their potential performance, the involved challenges have been identified and strategies to overcome the limitations have been proposed. Future research in this field should address these issues and challenges in addition to discovery of new materials.
关键词： metal oxides,p-type semiconductors,photoelectrochemical cell,photocathodes,solar water splitting
更新于2025-09-23 15:22:29
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Electrochromism: a fascinating branch of electrochemistry
摘要： This lecture on electrochromism and electrochromic devices starts with a short introduction to the field. This is followed by an overview of the different classes of electrochromic materials, in which each class is illustrated by some typical examples. The third part deals with some basic parameters to assess electrochromic compounds and devices. After this, we discuss the different types of electrochromic devices or elements, again always illustrated by some examples. Manufacturing considerations and real-world practical application examples of electrochromics are the topics of the last two parts of this lecture.
关键词： Electrochromic devices,Transition metal oxides,Electrochromism,Conducting polymers,Smart windows
更新于2025-09-23 15:21:21