Investigations of the Fe1.99Ti0.01O3–electrolyte interface

Aroutiounian, V. M.; Arakelyan, V. M.; Shahnazaryan, G. E.; Stepanyan, G. M.; Turner, John A.; Kocha, Shyam S.

doi:10.1016/s0013-4686(99)00421-1

Cited by 25 publications

(25 citation statements)

References 5 publications

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“…[13,17,25,27] The same conclusions can be drawn from the Bode plots e Fig. 5(b): the right-hand side peak in the Bode-phase diagram corresponds to the depletion layer, whereas the left-hand side peak arises from the impedance at the Helmholtz layer.…”

Section: Electrochemical Impedance Measurementssupporting

confidence: 67%

“…However, state-of-the-art photocurrent densities for PEC cells still remain in the range 2e3 mA cm À2 at 1.23 V RHE . The low quantum efficiency observed for these photoanodes is mainly related with the low mobility of charge carriers due to charge transfer hopping mechanisms [13]. In order to improve the energy efficiency of such devices, several efforts in shifting the activity of the photoanode into the visible have been developed in the past few years [14].…”

Section: Introductionmentioning

confidence: 99%

“…The present work reports the study of photoelectrochemical cells based on metal oxide semiconductor of undoped-hematite by current-voltage characteristics curves and also by using electrochemical impedance spectroscopy (EIS) in the dark and under illumination. The use of EIS analysis targeted to characterize the major internal charge transfer resistances that limit the performance of the cells under study with undopedFe 2 O 3 as photoanode [13,17]. Even though EIS is relatively easy to apply, the interpretation of the results is often complex and requires the use of suitable theoretical models.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Lopes

Andrade

Ribeiro

et al. 2010

International Journal of Hydrogen Energy

257

164

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a b s t r a c tThe photocurrent-voltage characteristic of a photoelectrochemical cell for solar hydrogen production via water splitting, using undoped-hematite as photoanode, was obtained.Photoelectrochemical characteristics of the cell were also investigated by electrochemical impedance spectroscopy. Both techniques were carried out in the dark and under illumination. The analysis of the frequency spectra for the real and imaginary parts of the complex impedance allowed obtaining equivalent electrical analogs for the PEC cell operating in the dark and under 1 sun simulated illumination. Additionally, different electrode configurations were used (two and three-electrode arrangements). The twoelectrode configuration allowed the study of the overall charge transfer phenomena occurring at the semiconductor, within the electrolyte and at the counter-electrode side of the cell, whereas the three-electrode configuration gave more detailed information concerning the double charged layer at the semiconductor/electrolyte interface.

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Section: Electrochemical Impedance Measurementssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Lopes

Andrade

Ribeiro

et al. 2010

International Journal of Hydrogen Energy

257

164

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“…One element represents the space charge region and the other corresponds to charge transfer and Helmholtz layer (see Figure 8 c). [133][134][135] Surface states are not specifically addressed with this model but are assumed to be closely coupled with the measured Helmholtz layer. Aroutounian et al [135] introduced a more complex system including the double RC model and a Warburg element characterizing a diffusion-limited process (in the space charge or in the Helmholtz layer).…”

Section: Advanced Understanding By Using Electrochemical Impedance Spmentioning

confidence: 99%

Solar Water Splitting: Progress Using Hematite (α‐Fe₂O₃) Photoelectrodes

2011

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Photoelectrochemical (PEC) cells offer the ability to convert electromagnetic energy from our largest renewable source, the Sun, to stored chemical energy through the splitting of water into molecular oxygen and hydrogen. Hematite (α-Fe(2)O(3)) has emerged as a promising photo-electrode material due to its significant light absorption, chemical stability in aqueous environments, and ample abundance. However, its performance as a water-oxidizing photoanode has been crucially limited by poor optoelectronic properties that lead to both low light harvesting efficiencies and a large requisite overpotential for photoassisted water oxidation. Recently, the application of nanostructuring techniques and advanced interfacial engineering has afforded landmark improvements in the performance of hematite photoanodes. In this review, new insights into the basic material properties, the attractive aspects, and the challenges in using hematite for photoelectrochemical (PEC) water splitting are first examined. Next, recent progress enhancing the photocurrent by precise morphology control and reducing the overpotential with surface treatments are critically detailed and compared. The latest efforts using advanced characterization techniques, particularly electrochemical impedance spectroscopy, are finally presented. These methods help to define the obstacles that remain to be surmounted in order to fully exploit the potential of this promising material for solar energy conversion.

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“…Currently, the major challenge in developing efficient PEC cells for water splitting relies on finding inexpensive materials that fulfill as much as possible the requirements of an ideal photoelectrode: i) it has to have strong light absorption in the visible spectrum, ii) high chemical stability in aqueous electrolyte solutions under dark and illuminated conditions, iii) suitable band edges positions for hydrogen and oxygen evolutions, iv) low kinetic overpotentials; and finally v) the charge transfer at the semiconductor/electrolyte interface must be selective for water splitting (Figure 1). [13,14] Oxide semiconductors (both n-and p-type) have been shown to be promisingly stable photoelectrodes for electrolysis of water. The most frequently studied photoelectrode materials are TiO2, WO3, Fe2O3, BiVO4 SnO2 and Cu2O and their modifications.…”

Section: Introductionmentioning

confidence: 99%

An innovative photoelectrochemical lab device for solar water splitting

Lopes

Dias

Andrade

et al. 2014

Solar Energy Materials and Solar Cells

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A photoelectrochemical (PEC) device capable of splitting water into storable hydrogen fuel by the direct use of solar energy is becoming a very attractive technology since it is clean and sustainable. Indeed, real field experiments are being developed in order to assess technological issues for large-scale usage under outdoor conditions. Following the need for developing photoelectrochemical devices with an optimized design that allows reaching a commercial performance level, the present works describes an innovative PEC cell for testing different photoelectrodes configurations, suitable for continuous operation and for easily collect the evolved gases. Moreover, a porous Teflon ® diaphragm useable for a wide range of aqueous electrolyte solutions is tested. Two semiconductors were investigated: tungsten trioxide and undoped hematite. The WO3 photoelectrodes were deposited in two different substrates: i) anodized WO3 photoelectrodes on a metal substrate and ii) WO3 deposited by blade spreading method on a TCO glass substrate.The undoped-Fe2O3 photoanode was deposited by ultrasonic spray pyrolysis technique in a TCO glass substrate. The material deposited on glass substrates allows to obtain transparent photoelectrodes. Photocurrent-voltage characteristics were obtained for all samples characterized under three different conditions: i) no membrane separating the anode and the cathode evolution; ii) using a Teflon ® diaphragm and iii) using a Nafion ® 212 membrane. The transparent samples (photoanodes deposited on glass substrates) produced the highest values of photocurrent when the Teflon ® diaphragm was used. This

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Investigations of the Fe1.99Ti0.01O3–electrolyte interface

Cited by 25 publications

References 5 publications

Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Solar Water Splitting: Progress Using Hematite (α‐Fe₂O₃) Photoelectrodes

An innovative photoelectrochemical lab device for solar water splitting

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Investigations of the Fe1.99Ti0.01O3–electrolyte interface

Cited by 25 publications

References 5 publications

Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy

Solar Water Splitting: Progress Using Hematite (α‐Fe2O3) Photoelectrodes

An innovative photoelectrochemical lab device for solar water splitting

Contact Info

Product

Resources

About

Solar Water Splitting: Progress Using Hematite (α‐Fe₂O₃) Photoelectrodes