Investigations of the structure of the iron oxide semiconductor–electrolyte interface

Aroutiounian, V. M.; Arakelyan, V. M.; Shahnazaryan, G. E.; Stepanyan, G. M.; Khachaturyan, E. A.; Turner, John A.

doi:10.1016/j.crci.2005.03.029

Cited by 14 publications

(17 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar shapes of the impedance diagrams were obtained by other researchers who performed EIS measurements with semiconductor electrodes such as iron oxides (Fe 1 [14]), boron-doped diamond films on molybdenum substrates [20], and Si, Sn and Zn-doped n-GaAs, n-InP and p-InP electrodes [18]. Aroutiounian [13,14] also suggested that the main contribution to the impedance at high frequencies (> 10 kHz) is the space charge layer of the semiconductor, while at low frequencies (< 10 kHz) a slow diffusion process dominates the impedance spectra.…”

Section: Equivalent Circuit Modelssupporting

confidence: 61%

“…Aroutiounian [13,14] also suggested that the main contribution to the impedance at high frequencies (> 10 kHz) is the space charge layer of the semiconductor, while at low frequencies (< 10 kHz) a slow diffusion process dominates the impedance spectra.…”

Section: Equivalent Circuit Modelsmentioning

confidence: 96%

“…Electrochemical impedance spectroscopy (EIS) is a powerful technique for studying the structure of the electrical double layer formed at the semiconductor electrode/electrolyte interface, the charge transfer processes in the semiconductor and electrolyte, as well as the parameters defining the limiting steps of the electrode processes [13,14]. Chaniotakis [11] used EIS experiments to show that the potentiometric sensitivity of GaN electrodes is controlled by the Helmholtz and Gouy layers formed at the GaN/ electrolyte interface.…”

Section: Introductionmentioning

confidence: 99%

“…The response of semiconductor electrodes is controlled by many factors such as the crystalline structure and surface properties of the semiconductor material, its corrosion resistance in aqueous electrolytes, the structure of the semiconductor electrode/electrolyte interface, and complex chemical and electrochemical processes taking place at the interface [13,14]. The investigation of these factors may help eliminate some of the problems associated with the application of GaN and In 0.2 Ga 0.8 N electrodes, including narrow range of linear response to changes in anionic activity, deviations of the electrode slope from the theoretical (Nerstian) value, limited reproducibility of measurements, and potential drift [12].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

et al. 2008

View full text Add to dashboard Cite

The response of potentiometric anion selective electrodes employing undoped GaN or In 0.2 Ga 0.8 N films as sensing element to detect various anions was investigated in solutions of KF, KNO 3 , KCl, HOC 6 H 4 COONa, KSCN, CH 3 COOK, KClO 4 and KBr salts. The calibration plots for the GaN and In 0.2 Ga 0.8 N semiconductor electrodes contained linear regions extending over four decades of activity change in most solutions. The structure of the GaN and In 0.2 Ga 0.8 N semiconductor electrode/ electrolyte interface was studied through electrochemical impedance spectroscopy. Analogous equivalent circuits modeling the GaN or In 0.2 Ga 0.8 N electrode/electrolyte interface were proposed and their parameters were calculated. The space charge layer of the GaN and In 0.2 Ga 0.8 N semiconductors dominated the impedance of the electrochemical system at high frequencies (> 10 kHz), whereas at low frequencies (< 10 kHz), the impedance was controlled by the diffusion of electroactive species across the layer of adsorbed ions at the surface of the electrode. Results imply a strong dependence of the electrodes performance on the adsorption capacity of tested anions.

show abstract

Section: Equivalent Circuit Modelssupporting

confidence: 61%

Section: Equivalent Circuit Modelsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

et al. 2008

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract