Particulate Film Electrodes Research Articles

Electrochemical impedance spectroscopy of WO3 photoanodes on different conductive substrates: The interfacial charge transport between semiconductor particles and Ti surface

Particulate film electrodes of n-type semiconductor oxides are promising for photoelectrochemical (PEC) water splitting. To improve the photoanodic performance, we investigated the effect of charge transport at the interface between the oxide particles and the conductive substrate using electrochemical impedance spectroscopy (EIS) under UV–visible light irradiation. As a model oxide, we prepared tungsten oxide (WO3) particle films on different conductive substrates of fluorine-doped tin oxide (FTO)-coated glass, indium tin oxide (ITO)-coated glass, and Ti plates at different calcination temperatures. The PEC properties of the WO3 electrodes were evaluated for water oxidation in 0.1 mol/L sulfuric acid. The photocurrent density of the WO3 films on Ti plate (Ti/WO3) monotonically increased as the calcination temperature increased up to 650 °C, whereas the WO3 films on FTO-coated and ITO-coated glasses were, as is well known, deactivated at such high temperatures. The EIS measurements of the Ti/WO3 photoanodes revealed that the series resistance (Rs) was low even after calcination at high temperatures. The charge-transfer resistance (Rct) of WO3 photoanodes estimated from EIS was dependent on the incident light intensity because the photocurrent density was proportional to the irradiance. We found that the Ti/WO3 photoanodes exhibited a resistance in addition to Rs and Rct. We assigned this resistance, which was not changed by the light intensity, to the interfacial charge transport resistance (Ri) between WO3 particles and the Ti substrate. A smaller Ri increased the photocurrent density of Ti/WO3 for the oxygen evolution reaction at higher applied potentials.

One-step Preparation and Photosensitivity of Size-quantized Cadmium Chalcogenide Nanoparticles Deposited on Porous Zinc Oxide Film Electrodes

Abstract Size-quantized cadmium chalcogenide nanoparticles were effectively deposited on a porous zinc oxide particulate film electrode by a one-step hydrothermal method in which an increase in the concentration of 3-mercaptopropionic acid reduced the size of deposited nanoparticles. The photoelectrochemical properties of the resulting electrodes varied depending on the kind of metal chalcogenide nanoparticles deposited and their size.

Effect of TiCl4 Treatment on Photoelectrochemical Properties of Nanocrystalline CdS Particulate Films

Cadmium sulfide (CdS) particulate film electrodes were prepared by coating nanosized CdS colloidal sols onto fluorine-doped tin oxide conducting glass, and treated with titanium tetrachloride aqueous solution. The variation of photoelectrochemical properties of these electrodes according to the surface treatment was investigated with respect to photocurrent and surface morphology. Porous films composed of coarsely interconnected CdS particles before treatment became more compact and stable after treatment. It was also found that the component was formed homogeneously throughout the entire film. This etching and effect brought about densification of the films, a decrease of film surface area, and an enhancement of the photocurrent. Especially, the stabilities of the electrodes measured by chronoamperometry were remarkably improved by the treatment, suggesting the effectiveness of this approach. © 2001 The Electrochemical Society. All rights reserved.

Preparation and Photoelectrochemical Properties of TiO2 Films Consisting of Monodispersed Particles by Sol-Gel Method

Monodispersed submicron TiO2 particles have been prepared from Ti(OC2H5)4solutions containing HPC, and deposited on mesa silica glass substrates to obtain particulate TiO2 film electrodes. The particle size was controlled to be 0.7, 0.3 and 0.15 μm by changing the amount of water used for alkoxide hydrolysis. The particulate film electrode with the largest particles showed the highest anodic photocurrent under white light illumination and the highest anodic UV and visible light photoresponse. Based on the results obtained, the effects of the particle size on the photoelectrochemical properties have been discussed.

Photocorrosion of Coupled CdS/CdSe Photoelectrodes Coated with ZnO: Atomic Force Microscopy and X‐Ray Diffraction Studies

The stability of photoelectrochemical cells based on chemically deposited CdS/CdSe coupled films has been examined. Changes in surface structure and composition of coated and uncoated coupled films as well as CdSe films have been examined by atomic force microscopy and X‐ray diffraction. The superior stability at short times of the coupled system, compared to CdSe, is related to the increase in the hexagonal character (stronger bonding) and the smaller recombination rate of the photogenerated carriers. At large operation times, the lower stability of the coupled system is related to band opening, which increases the oxidation rates of the passivating Se/S layer. The recrystallization illuminated CdSe photoanodes, and coupled films working in the dark can be explained by the presence of surface states and back reactions. Stable short‐circuit currents were obtained with coupled films coated with a thin layer (350 Å) of ZnO. It is likely that oxidation and redeposition of the protective ZnO film competes for hole consumption. The rough morphology of the coated photoelectrodes correlates to a substantial increase in surface area that resembles ZnO particulate film electrodes sensitized by CdSe and CdS.

Photoelectrochemical decomposition of amino acids on a TiO 2/OTE particulate film electrode

The photoelectrochemical degradation of amino acids and derivatives such as glutamic acid, glutamine, glutaric acid, lysine, β-alanine, 8-aminooctanoic acid and phenylalanine has been examined on an irradiated TiO 2/OTE particulate film electrode. The photooxidative disappearance of the substrates ultimately transforms the nitrogen into NO 3 − and NH 3 (as ammonium ions under our conditions), whereas the carbonaceous residues are converted into CO 2. Variations in photocurrent were observed during the temporal course of the photodegradative process. The rates of conversion and the quantity of degraded products depend on the external applied bias and appear to be closely related to the molecular structure of the substrates. A photoelectrochemical degradative pathway is discussed briefly on the basis of the experimental observations.

Photoelectrochemical Studies on Dye‐Sensitized Particulate ZnO Thin‐Film Photoelectrodes in Nonaqueous Media

For dye‐sensitized solar cells, it is advantageous to use semiconductor electrodes in the form of thin particulate films (prepared from nanometer‐sized colloidal particles) owing to their large surface area. The present report shows that nanocrystalline particulate ZnO thin film electrodes sensitized by rhodamine B give excellent photoresponse in nonaqueous media under visible light illumination. Even by monochromatic light (λ = 550 nm) of low intensity (300 μW/cm2), high open‐circuit photopotentials up to 280 mV were generated using these electrodes. Under short‐circuit conditions, the maximum incident photons to current conversion efficiency was found to be 8.5% at the peak wavelength of 555 nm in acetonitrile medium. The electrodes were found to be fairly stable in nonaqueous solvents and gave considerably high conversion efficiencies and fill factors. These relatively high efficiencies are indicative of low recombination losses in nanocrystalline particulate film electrodes.

A mechanistic study of the photoelectrochemical oxidation of organic compounds on a TiO 2/TCO particulate film electrode assembly

The photo-oxidative degradation of sodium benzene sulfonate, 2-phenoxyethanol, ethyleneglycol, diethyleneglycol, acetic acid and formic acid, was examined on a TiO 2 particulate film immobilized on a transparent conductive oxide (TCO) glass electrode assembly. The photocurrents generated during the photodegradation of these organic compounds were monitored. Formation of intermediate species (acetic acid and formic acid) during the temporal course of the photo-oxidative process(es) appears to have a direct effect on the photocurrents.

Photoelectrochemical Decomposition of Surfactants on a TiO2/TCO Particulate Film Electrode Assembly

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoelectrochemical Decomposition of Surfactants on a TiO2/TCO Particulate Film Electrode AssemblyHisao Hidaka, Yuichi Asai, Jincai Zhao, Kayo Nohara, Ezio Pelizzetti, and Nick SerponeCite this: J. Phys. Chem. 1995, 99, 20, 8244–8248Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1 May 1995https://doi.org/10.1021/j100020a056RIGHTS & PERMISSIONSArticle Views413Altmetric-Citations64LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts

Electrochemically assisted photocatalysis: titania particulate film electrodes for photocatalytic degradation of 4-chlorophenol

A commercially available TiO[sub 2] powder (Degussa P25) has been used to prepare thin particulate films on conducting glass plates. These semiconductor particulate films are photoelectrochemically active with properties similar to an n-type semiconductor. The recombination between the photogenerated charge carriers can be suppressed by applying an external anodic bias. Electron scavengers, such as oxygen, affect the photocurrent generation by competing for the photogenerated electrons. These particulate films provide a convenient method for accelerating the photocatalytic reaction by applying an external bias. For example, the rate of photocatalytic degradation of 4-chlorophenol greatly increases when the TiO[sub 2] particulate film electrode is maintained at an external anodic bias (0.6 V vs SCE) during the UV photolysis. 26 refs., 6 figs.