Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

TiO₂@Cu₂O n-n Type Heterostructures for Photochemistry.

ABSTRACT: A TiO₂@Cu₂O semiconductor heterostructure with better photochemical response compared to TiO₂ was obtained using an electrochemical deposition method of Cu₂O on the surface of TiO₂ nanotubes. The choice of 1D nanotubes was motivated by the possibility of achieving fast charge transfer, which is considered best suited for photochemical applications. The morphology and structural properties of the obtained heterojunction were determined using standard methods -SEM and Raman spectroscopy. Analysis of photoelectrochemical properties showed that TiO₂@Cu₂O heterostructures exhibit better properties resulting from an interaction with sunlight than TiO₂. A close relationship between the morphology of the heterostructures and their photoproperties was also demonstrated. Investigations representing a combination of photoelectrochemical cells for hydrogen production and photocatalysis-photoelectrocatalysis-were also carried out and confirmed the observations on the photoproperties of heterostructures. Analysis of the Mott-Schottky plots as well as photoelectrochemical measurements (I_ph-V, I_ph-t) showed that TiO₂ as well as, unusually, Cu₂O exhibit n-type conductivity. On this basis, a new energy diagram of the TiO₂@Cu₂O system was proposed. It was found that TiO₂@Cu₂O n-n type heterostructure prevents the processes of photocorrosion of copper(I) oxide contained in a TiO₂-based heterostructure.

SUBMITTER: Trenczek-Zajac A

PROVIDER: S-EPMC8269846 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Catalysis of Organic Pollutants Abatement Based on Pt-Decorated Ag@Cu2O Heterostructures.

Project description:Pt-decorated Ag@Cu2O heterostructures were successfully synthesized using a simple and convenient method. The Pt nanoparticle density on the Ag@Cu2O can be controlled by changing the concentration of the Pt precursor. The synthesized Ag@Cu2O-Pt nanoparticles exhibited excellent catalytic performance, which was greatly affected by changes in the Ag@Cu2O-Pt structure. To optimize the material's properties, the synthesized Ag@Cu2O-Pt nanoparticles were used to catalyze toxic pollutants and methyl orange (MO), and nontoxic products were obtained by catalytic reduction. The Pt-decorated Ag@Cu2O nanoparticles showed excellent catalytic activity, which significantly decreased the pollutant concentration when the nanoparticles were used for catalytic reduction. The redistribution of charge transfer is the nanoparticles' main contribution to the catalytic degradation of an organic pollutant. This Pt-decorated Ag@Cu2O material has unique optical and structural characteristics that make it suitable for photocatalysis, local surface plasmon resonance, and peroxide catalysis.

| S-EPMC6696002 | biostudies-literature

Effect of Cu2O Substrate on Photoinduced Hydrophilicity of TiO2 and ZnO Nanocoatings.

Project description:The effect of a Cu2O substrate on the photoinduced alteration of the hydrophilicity of TiO2 and ZnO surfaces was studied. It was demonstrated that the formation of heterostructures Cu2O/TiO2 and Cu2O/ZnO strongly changed the direction of the photoinduced alteration of surface hydrophilicity: while both TiO2 and ZnO demonstrate surface transition to superhydrophilic state under UV irradiation and no significant alteration of the surface hydrophilicity under visible light irradiation, the formation of Cu2O/TiO2 and Cu2O/ZnO heterostructures resulted in photoinduced decay of the surface hydrophilicity caused by both UV and visible light irradiation. All observed photoinduced changes of the surface hydrophilicity were compared and analyzed in terms of photoinduced alteration of the surface free energy and its polar and dispersive components. Alteration of the photoinduced hydrophilic behavior of TiO2 and ZnO surfaces caused by formation of the corresponding heterostructures with Cu2O are explained within the mechanism of electron transfer and increasing of the electron concentration on the TiO2 and ZnO surfaces.

| S-EPMC8226581 | biostudies-literature

Au-Mediated Charge Transfer Process of Ternary Cu2O/Au/TiO2-NAs Nanoheterostructures for Improved Photoelectrochemical Performance.

Project description:Based on a facile three-step preparation method, Cu2O/Au/TiO2-NAs ternary heterojunction nanocomposites have been successfully synthesized by electrodepositing a Cu2O layer on the surface of Au nanoparticles (NPs) decorated highly ordered TiO2 nanotube arrays (NAs). The structure, surface morphology, chemical composition, and optical and intrinsic defects properties of the as-prepared samples are characterized by transmission and scanning electron microscopy (TEM and SEM), X-ray diffraction (XRD), UV-vis light absorbance spectra, Raman scattering, and X-ray photoelectron spectroscopy (XPS). Simultaneously, the Cu2O/Au/TiO2-NAs ternary nanohybrids exhibited progressively improved photoelectrocatalytic (PEC) performance compared with the dual Cu2O/TiO2-NAs type-II nanoheterojunctions, confirming by the photocurrent density versus testing time curve (amperometric I-t curve), open-circuit potential versus testing time curve (V oc-t curve), and electrochemical impedance spectroscopy (EIS) measurements, which were mainly ascribed to the synergistic effect of reduced interfacial charge transfer resistance and boosted energetic charge carriers generation associated with embedding Au NPs. Furthermore, the self-consistent charge transfer mechanism of Z-scheme and interband transitions mediated with Au NPs for Cu2O/Au/TiO2-NAs triple nanocomposites is proposed, which was evaluated by nanosecond time-resolved transient photoluminescence (NTRT-PL) spectra excited by 266 and 400 nm, respectively. Following this scheme, UV-vis light photocatalytic activities of Cu2O/Au/TiO2-NAs ternary nanohybrids were elaborated toward photodegradation of methyl orange (MO) in aqueous solution, and the photodegradation rate of optimum triple nanocomplex was found to be 90%.

| S-EPMC7144151 | biostudies-literature

Ferroelectric Polarization-Enhanced Photocatalysis in BaTiO3-TiO2 Core-Shell Heterostructures.

Project description:Suppressing charge recombination and improving carrier transport are key challenges for the enhancement of photocatalytic activity of heterostructured photocatalysts. Here, we report a ferroelectric polarization-enhanced photocatalysis on the basis of BaTiO3-TiO2 core-shell heterostructures synthesized via a hydrothermal process. With an optimal weight ratio of BaTiO3 to TiO2, the heterostructures exhibited the maximum photocatalytic performance of 1.8 times higher than pure TiO2 nanoparticles. The enhanced photocatalytic activity is attributed to the promotion of charge separation and transport based on the internal electric field originating from the spontaneous polarization of ferroelectric BaTiO3. High stability of polarization-enhanced photocatalysis is also confirmed from the BaTiO3-TiO2 core-shell heterostructures. This study provides evidence that ferroelectric polarization holds great promise for improving the performance of heterostructured photocatalysts.

| S-EPMC6722819 | biostudies-other

Comparative photochemistry of animal type 1 and type 4 cryptochromes.

Project description:Cryptochromes (CRYs) are blue-light photoreceptors with known or presumed functions in light-dependent and light-independent gene regulation in plants and animals. Although the photochemistry of plant CRYs has been studied in some detail, the photochemical behavior of animal cryptochromes remains poorly defined in part because it has been difficult to purify animal CRYs with their flavin cofactors. Here we describe the purification of type 4 CRYs of zebrafish and chicken as recombinant proteins with full flavin complement and compare the spectroscopic properties of type 4 and type 1 CRYs. In addition, we analyzed photoinduced proteolytic degradation of both types of CRYs in vivo in heterologous systems. We find that even though both types of CRYs contain stoichiometric flavin, type 1 CRY is proteolytically degraded by a light-initiated reaction in Drosophila S2, zebrafish Z3, and human HEK293T cell lines, but zebrafish CRY4 (type 4) is not. In vivo degradation of type 1 CRYs does not require continuous illumination, and a single light flash of 1 ms duration leads to degradation of about 80% of Drosophila CRY in 60 min. Finally, we demonstrate that in contrast to animal type 2 CRYs and Arabidopsis CRY1 neither insect type 1 nor type 4 CRYs have autokinase activities.

| S-EPMC2739604 | biostudies-other

Improving the Photocatalytic Activity of Mesoporous Titania Films through the Formation of WS2/TiO2 Nano-Heterostructures.

Project description:Heterostructures formed by anatase nanotitania and bidimensional semiconducting materials are expected to become the next-generation photocatalytic materials with an extended operating range and higher performances. The capability of fabricating optically transparent photocatalytic thin films is also a highly demanded technological issue, and increasing the performances of such devices would significantly impact several applications, from self-cleaning surfaces to photovoltaic systems. To improve the performances of such devices, WS2/TiO2 heterostructures obtained by incorporating two-dimensional transition metal dichalcogenides layers into titania mesoporous ordered thin films have been fabricated. The self-assembly process has been carefully controlled to avoid disruption of the order during film fabrication. WS2 nanosheets of different sizes have been exfoliated by sonication and incorporated in the mesoporous films via one-pot processing. The WS2 nanosheets result as well-dispersed within the titania anatase mesoporous film that retains a mesoporous ordered structure. An enhanced photocatalytic response due to an interparticle electron transfer effect has been observed. The structural characterization of the heterostructure has revealed a tight interplay between the matrix and nanosheets rather than a simple additive co-catalyst effect.

| S-EPMC9000319 | biostudies-literature

Negative Oxygen Ions Production by Superamphiphobic and Antibacterial TiO2/Cu2O Composite Film Anchored on Wooden Substrates.

Project description:According to statistics, early in the 20th century, the proportion of positive and negative air ions on the earth is 1 : 1.2. However, after more than one century, the equilibrium state of the proportion had an obvious change, which the proportion of positive and negative air ions became 1.2 : 1, leading to a surrounding of positive air ions in human living environment. Therefore, it is urgent to adopt effective methods to improve the proportion of negative oxygen ions, which are known as "air vitamin". In this study, negative oxygen ions production by the TiO2/Cu2O-treated wood under UV irradiation was first reported. Anatase TiO2 particles with Cu2O particles were doped on wooden substrates through a two-step method and further modification is employed to create remarkable superamphiphobic surface. The effect of Cu2O particles dopant on the negative oxygen ions production of the TiO2-treated wood was investigated. The results showed that the production of negative oxygen ions was drastically improved by doping with Cu2O particles under UV irradiation. The wood modified with TiO2/Cu2O composite film after hydrophobization is imparted with superamphiphobicity, antibacterial actions against Escherichia coli, and negative oxygen ions production under UV irradiation.

| S-EPMC4882552 | biostudies-other

Optimal n-Type Al-Doped ZnO Overlayers for Charge Transport Enhancement in p-Type Cu2O Photocathodes.

Project description:An effective strategy for improving the charge transport efficiency of p-type Cu2O photocathodes is the use of counter n-type semiconductors with a proper band alignment, preferably using Al-doped ZnO (AZO). Atomic layer deposition (ALD)-prepared AZO films show an increase in the built-in potential at the Cu2O/AZO interface as well as an excellent conformal coating with a thin thickness on irregular Cu2O. Considering the thin thickness of the AZO overlayers, it is expected that the composition of the Al and the layer stacking sequence in the ALD process will significantly influence the charge transport behavior and the photoelectrochemical (PEC) performance. We designed various stacking orders of AZO overlayers where the stacking layers consisted of Al2O3 (or Al) and ZnO using the atomically controlled ALD process. Al doping in ZnO results in a wide bandgap and does not degrade the absorption efficiency of Cu2O. The best PEC performance was obtained for the sample with an AZO overlayer containing conductive Al layers in the bottom and top regions. The Cu2O/AZO/TiO2/Pt photoelectrode with this overlayer exhibits an open circuit potential of 0.63 V and maintains a high cathodic photocurrent value of approximately -3.2 mA cm-2 at 0 VRHE for over 100 min.

| S-EPMC8004703 | biostudies-literature

General and controllable synthesis strategy of metal oxide/TiO2 hierarchical heterostructures with improved lithium-ion battery performance.

Project description:We demonstrate a simple, efficient, yet versatile strategy for the synthesis of novel hierarchical heterostructures composed of TiO(2) nanofiber stem and various metal oxides (MOs) secondary nanostructures, including Co(3)O(4), Fe(2)O(3), Fe(3)O(4), and CuO, by advantageously combining the versatility of the electrospinning technique and hydrothermal growth method, for which the controllable formation process and possible formation mechanism are also investigated. Moreover, as a proof-of-concept demonstration of the functional properties of these hierarchical heterostructures, the Co(3)O(4)/TiO(2) hierarchical heterostructures are investigated as the lithium-ion batteries (LIBs) anode materials for the first time, which not only delivers a high reversible capacity of 632.5 mAh g(-1) and 95.3% capacity retention over 480 cycles, but also shows excellent rate capability with respect to the pristine TiO(2) nanofibers. The synergetic effect between Co(3)O(4) and TiO(2) as well as the unique feature of hierarchical heterostructures are probably responsible for the enhanced electrochemical performance.

| S-EPMC3463005 | biostudies-literature

Thermoelectric Properties of p-Type Cu2O, CuO, and NiO from Hybrid Density Functional Theory.

Project description:The electronic transport coefficients of three Earth-abundant metal oxides Cu2O, CuO, and NiO were investigated using hybrid density functional theory (DFT). Hybrid DFT methods combined with local Gaussian-type basis sets enabled band structure studies on both non-magnetic and magnetic p-type metal oxides without empirical corrections. The CRYSTAL code was used for obtaining the wavefunction, and the transport properties were calculated with two different methodologies to benchmark their accuracy: a numerical approach as implemented in the BoltzTraP code and an analytical approach recently implemented in CRYSTAL17. Both computational methods produce identical results in good agreement with experimental measurements of the Seebeck coefficient. The predicted electrical conductivities are overestimated, owing likely to the used approximation of a constant electronic relaxation time in the calculations, as explicit electron scattering is neglected and relaxation time is considered only as a free parameter. The obtained results enable us to critically review and complement the available theoretical and experimental literature on the studied p-type thermoelectric metal oxide materials.

| S-EPMC6150688 | biostudies-literature