Characterization of TiO2-based semiconductors for photocatalysis by electrochemical impedance spectroscopy

Ângelo, Joana; Magalhães, Pedro; Andrade, Luísa; Mendes, Adélio

doi:10.1016/j.apsusc.2016.06.101

Cited by 109 publications

(42 citation statements)

References 35 publications

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“…This enables the determination of two capacitive contributions involved in the measured impedance spectra . For the reduced structures, the peak at higher frequency shifts to lower frequencies, this can originate from the incorporation of Ti 3+ species in the reduced sample ,. The increase in the Ti 3+ concentration decreases the resistivity, and thus shifts the time constant of space charge transfer towards a higher value (Figure b).…”

Section: Resultsmentioning

confidence: 99%

Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

et al. 2019

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Cu doping in titania is usually detrimental to the material's photoconductivity, which prevents the use of this combination in photoanodes. In this work, we produce TiO 2 nanotube arrays intrinsically doped with copper and establish sufficient conductivity to use them as efficient photoanodes for methanol oxidation in a photoelectrochemical hydrogen generation setting. Firstly, Cu-doped TiO 2 nanotubes were produced by anodizing a TiÀ Cu binary alloy. By subsequent thermal reduction of the structure in an Ar/H 2 environment, conductive copper-doped TiO 2 nanotubes (TiCuTNÀ Ar/H 2 ) can be achieved with an approximately 10 3 times higher conductivity than the non-reduced material. When these reduced Cu-doped TiO 2 nanotubes are used as photoanode, copper species embedded in the TiO 2 wall catalyze the methanol oxidation reaction. As a result of the combined effect of conductivity and catalytic effect of Cu, such reduced Cu:TiO 2 nanotubes can generate a photocurrent of 0.76 mA cm À 2 at 1 V vs. RHE, under AM1.5 (100 mW/ Cm 2 ) irradiation -in a 50 : 50 MeOH/water solution -this is 33 times higher than for pristine Cu:TiO 2 nanotubes.[a] S.

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Section: Resultsmentioning

confidence: 99%

Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

et al. 2019

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“…EIS spectra show no frequency‐dependent mechanism or competing contributions at high frequencies (second hemispheres), thus the whole spectra might be considered as a single contribution. Many circuits can be considered in order to model the general behavior of the samples . Among others, electric equivalent circuit (EEQC) shown in Figure e (inset) was proposed for electrode materials investigated within this work and the spectra created with the fitting data were included in Figure S5 in the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Photoelectrochemically Active N‐Adsorbing Ultrathin TiO₂ Layers for Water‐Splitting Applications Prepared by Pyrolysis of Oleic Acid on Iron Oxide Nanoparticle Surfaces under Nitrogen Environment

Kertmen

Barbé

Szkoda

et al. 2018

Adv Materials Inter

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Highly performing photocatalytic surfaces are nowadays highly desirable in energy fields, mainly due to their applicability as photo water‐splitting electrodes. One of the current challenges in this field is the production of highly controllable and efficient photoactive surfaces on many substrates. Atomic layer deposition has allowed the deposition of photoactive TiO2 layers over wide range of materials and surfaces. However, nitrogen doping of the growing layers, a highly effective way of controlling the absorption edges of photoactive surfaced, is still a challenging task. Here, the preparation of hierarchical nanostructured surfaces based on Langmuir–Schaefer and atomic layer deposition is proposed. Ultrathin TiO2 layers that are photoelectrochemically active in water splitting are prepared by a relatively low‐temperature catalytic decomposition of oleic acid capping layers of iron oxide nanoparticles and the posterior nitrogen adsorption. The results evidence that simple N‐adsorption is sufficient to narrow the bandgap of TiO2 layers that is equal to bandgap narrowing (0.12 eV) observed for substitutionally N‐doped materials. The photocatalytic activity tests of the prepared surfaces in water‐splitting applications demonstrate ≈90% increase in the activity of the N‐adsorbing TiO2 layers.

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“…Titanium dioxide (TiO 2 ) is the most crystalline semiconductor used in photocatalytic process [26,32]. It presents three polymorphic phases: anatase and rutile, with tetragonal structure; and brookite, orthorhombic [33,34], being anatase the phase of greater degradative efficiency [17].…”

Section: Introductionmentioning

confidence: 99%

“…Recent researches deal with heterogeneous photocatalysis for applications in water treatment [2,6,23,26]. Figure 3 shows the schematic diagram of photocatalytic process, showing the photoactivation of a catalyst semiconductor and the production of oxidizing radicals.…”

Section: Introductionmentioning

confidence: 99%

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Titanium Dioxide Films for Photocatalytic Degradation of Methyl Orange Dye

Bento¹,

Pillis²

2018

Titanium Dioxide - Material for a Sustainable Environment

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The aim of this work was to characterize and evaluate the influence of the thickness on the photocatalytic efficiency of titanium dioxide thin films on the degradation of methyl orange dye under UV light irradiation. The films of 280 and 468 nm thick were deposited on borosilicate substrates at 400°C by the MOCVD technique using titanium isoproxide IV as precursor. XRD analyses showed the formation of anatase-TiO 2 phase. Crosssectional FE-SEM images show that the films presented a dense columnar structure and grown perpendicularly to the substrate surface. The photocatalytic activity of the catalysts was studied using UV-vis spectrophotometry The TiO 2 film with 468 nm of thickness presented higher photocatalytic activity exhibiting 69% of dye degradation. The increase of grain size and thickness of the films promoted an improvement of photocatalytic efficiency.

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Characterization of TiO2-based semiconductors for photocatalysis by electrochemical impedance spectroscopy

Cited by 109 publications

References 35 publications

Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Photoelectrochemically Active N‐Adsorbing Ultrathin TiO₂ Layers for Water‐Splitting Applications Prepared by Pyrolysis of Oleic Acid on Iron Oxide Nanoparticle Surfaces under Nitrogen Environment

Titanium Dioxide Films for Photocatalytic Degradation of Methyl Orange Dye

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Characterization of TiO2-based semiconductors for photocatalysis by electrochemical impedance spectroscopy

Cited by 109 publications

References 35 publications

Conductive Cu‐Doped TiO2 Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Conductive Cu‐Doped TiO2 Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Photoelectrochemically Active N‐Adsorbing Ultrathin TiO2 Layers for Water‐Splitting Applications Prepared by Pyrolysis of Oleic Acid on Iron Oxide Nanoparticle Surfaces under Nitrogen Environment

Titanium Dioxide Films for Photocatalytic Degradation of Methyl Orange Dye

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Product

Resources

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Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Conductive Cu‐Doped TiO₂ Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation

Photoelectrochemically Active N‐Adsorbing Ultrathin TiO₂ Layers for Water‐Splitting Applications Prepared by Pyrolysis of Oleic Acid on Iron Oxide Nanoparticle Surfaces under Nitrogen Environment