scholarly journals Photoelectrochemical Response of WO3/Nanoporous Carbon Anodes for Photocatalytic Water Oxidation

2018 ◽  
Vol 4 (3) ◽  
pp. 45 ◽  
Author(s):  
Alicia Gomis-Berenguer ◽  
Jesús Iniesta ◽  
David Fermín ◽  
Conchi Ania
Keyword(s):  
Water Oxidation ◽  
Carrier Transport ◽  
Hexagonal Phase ◽  
Nanoporous Carbon ◽  
Photoelectrochemical Performance ◽  
Nanoporous Carbons ◽  
Photoelectrochemical Activity ◽  
Photoelectrochemical Response ◽  
Carbon Anodes ◽  
The Impact

This work demonstrates the ability of nanoporous carbons to boost the photoelectrochemical activity of hexagonal and monoclinic WO3 towards water oxidation under irradiation. The impact of the carbonaceous phase was strongly dependent on the crystalline structure and morphology of the semiconductor, substantially increasing the activity of WO3 rods with hexagonal phase. The incorporation of increasing amounts of a nanoporous carbon of low functionalization to the WO3 electrodes improved the quantum yield of the reaction and also affected the dynamics of the charge transport, creating a percolation path for the majority carriers. The nanoporous carbon promotes the delocalization of the charge carriers through the graphitic layers. We discuss the incorporation of nanoporous carbons as an interesting strategy for improving the photoelectrochemical performance of nanostructured semiconductor photoelectrodes featuring hindered carrier transport.

scholarly journals Influence of C3N4 Precursors on Photoelectrochemical Behavior of TiO2/C3N4 Photoanode for Solar Water Oxidation

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 974 ◽  
Author(s):  
Swetha S. M. Bhat ◽  
Sang Eon Jun ◽  
Sol A Lee ◽  
Tae Hyung Lee ◽  
Ho Won Jang
Keyword(s):  
Water Oxidation ◽  
Photocurrent Density ◽  
Continuous Illumination ◽  
Photoelectrochemical Performance ◽  
Photoelectrochemical Activity ◽  
Energy Demands ◽  
Photoelectrochemical Response ◽  
Solar Water Oxidation ◽  
Redox Ability ◽  
2D Nanosheets

Photoelectrochemical water splitting is considered as a long-term solution for the ever-increasing energy demands. Various strategies have been employed to improve the traditional TiO2 photoanode. In this study, TiO2 nanorods were decorated by graphitic carbon nitride (C3N4) derived from different precursors such as thiourea, melamine, and a mixture of thiourea and melamine. Photoelectrochemical activity of TiO2/C3N4 photoanode can be modified by tuning the number of precursors used to synthesize C3N4. C3N4 derived from the mixture of melamine and thiourea in TiO2/C3N4 photoanode showed photocurrent density as high as 2.74 mA/cm2 at 1.23 V vs. RHE. C3N4 synthesized by thiourea showed particle-like morphology, while melamine and melamine with thiourea derived C3N4 yielded two dimensional (2D) nanosheets. Nanosheet-like C3N4 showed higher photoelectrochemical performance than that of particle-like nanostructures as specific surface area, and the redox ability of nanosheets are believed to be superior to particle-like nanostructures. TiO2/C3N4 displayed excellent photostability up to 20 h under continuous illumination. Thiourea plays an important role in enhancing the photoelectrochemical performance of TiO2/C3N4. This study emphasizes the fact that the improved photoelectrochemical performance can be achieved by varying the precursors of C3N4 in TiO2/C3N4 heterojunction. This is the first report to show the influence of C3N4 precursors on photoelectrochemical performance in TiO2/C3N4 systems. This would pave the way to explore different precursors influence on C3N4 with respect to the photoelectrochemical response of TiO2/C3N4 heterojunction photoanode.

Determining the Role of Oxygen Vacancies in the Photocatalytic Performance of WO3 for Water Oxidation

2019 ◽  
Author(s):  
Sacha Corby ◽  
Laia Francàs ◽  
Andreas Kafizas ◽  
James R Durrant
Keyword(s):  
Oxygen Vacancy ◽  
Charge Carrier ◽  
Water Oxidation ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Photoelectrochemical Performance ◽  
Solar Water Splitting ◽  
The Impact ◽  
Recombination Kinetics ◽  
Vacancy Concentrations

Oxygen vacancies are common to most metal oxides, whether intentionally incorporated or otherwise, and the study of these defects is of increasing interest for solar water splitting. In this work, we examine nanostructured WO<sub>3</sub> photoanodes of varying oxygen content to determine how the concentration of bulk oxygen-vacancy states affects the photocatalytic performance for water oxidation. Using transient optical spectroscopy, we follow the charge carrier recombination kinetics in these samples, from picoseconds to seconds, and examine how differing oxygen vacancy concentrations impact upon these kinetics. We find that samples with an intermediate concentration of vacancies (~2% of oxygen atoms) afford the greatest photoinduced charge carrier densities, and the slowest recombination kinetics across all timescales studied. This increased yield of photogenerated charges correlates with improved photocurrent densities under simulated sunlight, with both greater and lesser oxygen vacancy concentrations resulting in enhanced recombination losses and poorer J-V performances. Our conclusion, that an optimal – neither too high nor too low – concentration of oxygen vacancies is required for optimum photoelectrochemical performance, is discussed in terms of the impact of these defects on charge separation and transport, as well as the implications held for other highly doped materials for photoelectrochemical water oxidation.

Determining the Role of Oxygen Vacancies in the Photocatalytic Performance of WO3 for Water Oxidation

2019 ◽  
Author(s):  
Sacha Corby ◽  
Laia Francàs ◽  
Andreas Kafizas ◽  
James R Durrant
Keyword(s):  
Oxygen Vacancy ◽  
Charge Carrier ◽  
Water Oxidation ◽  
Oxygen Vacancies ◽  
Photocatalytic Performance ◽  
Photoelectrochemical Performance ◽  
Solar Water Splitting ◽  
The Impact ◽  
Recombination Kinetics ◽  
Vacancy Concentrations

Oxygen vacancies are common to most metal oxides, whether intentionally incorporated or otherwise, and the study of these defects is of increasing interest for solar water splitting. In this work, we examine nanostructured WO<sub>3</sub> photoanodes of varying oxygen content to determine how the concentration of bulk oxygen-vacancy states affects the photocatalytic performance for water oxidation. Using transient optical spectroscopy, we follow the charge carrier recombination kinetics in these samples, from picoseconds to seconds, and examine how differing oxygen vacancy concentrations impact upon these kinetics. We find that samples with an intermediate concentration of vacancies (~2% of oxygen atoms) afford the greatest photoinduced charge carrier densities, and the slowest recombination kinetics across all timescales studied. This increased yield of photogenerated charges correlates with improved photocurrent densities under simulated sunlight, with both greater and lesser oxygen vacancy concentrations resulting in enhanced recombination losses and poorer J-V performances. Our conclusion, that an optimal – neither too high nor too low – concentration of oxygen vacancies is required for optimum photoelectrochemical performance, is discussed in terms of the impact of these defects on charge separation and transport, as well as the implications held for other highly doped materials for photoelectrochemical water oxidation.

scholarly journals The Impact of Ligand Carboxylates on Electrocatalyzed Water Oxidation

2021 ◽  
Vol 54 (17) ◽  
pp. 3326-3337
Author(s):  
Biswanath Das ◽  
Ahibur Rahaman ◽  
Andrey Shatskiy ◽  
Oscar Verho ◽  
Markus D. Kärkäs ◽  
...  
Keyword(s):  
Water Oxidation ◽  
The Impact

scholarly journals Characteristics of P-Type and N-Type Photoelectrochemical Biosensors: A Case Study for Esophageal Cancer Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1065
Author(s):  
Joseph-Hang Leung ◽  
Hong-Thai Nguyen ◽  
Shih-Wei Feng ◽  
Sofya B. Artemkina ◽  
Vladimir E. Fedorov ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Cancer Cells ◽  
Carrier Transport ◽  
X Ray Diffraction ◽  
Photoelectrochemical Response ◽  
Carrier Separation ◽  
Human Esophageal Cancer ◽  
P Type ◽  
Esophageal Cancer Cells

P-type and N-type photoelectrochemical (PEC) biosensors were established in the laboratory to discuss the correlation between characteristic substances and photoactive material properties through the photogenerated charge carrier transport mechanism. Four types of human esophageal cancer cells (ECCs) were analyzed without requiring additional bias voltage. Photoelectrical characteristics were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis reflectance spectroscopy, and photocurrent response analyses. Results showed that smaller photocurrent was measured in cases with advanced cancer stages. Glutathione (L-glutathione reduced, GSH) and Glutathione disulfide (GSSG) in cancer cells carry out redox reactions during carrier separation, which changes the photocurrent. The sensor can identify ECC stages with a certain level of photoelectrochemical response. The detection error can be optimized by adjusting the number of cells, and the detection time of about 5 min allowed repeated measurement.

Enhanced photoelectrochemical performance of internally porous Au-embedded α-Fe2O3 photoanodes for water oxidation

2017 ◽  
Vol 53 (30) ◽  
pp. 4278-4281 ◽  
Author(s):  
Pravin S. Shinde ◽  
Su Yong Lee ◽  
Jungho Ryu ◽  
Sun Hee Choi ◽  
Jum Suk Jang
Keyword(s):  
Water Oxidation ◽  
Photoelectrochemical Performance ◽  
Oxidation Performance ◽  
Photoelectrochemical Water Oxidation

We report CTAB-mediated synthesis of internally porous Au-embedded hematite photoanode with enhanced photoelectrochemical water oxidation performance.

Ultrasonic-assisted preparation of a pinhole-free BiVO4 photoanode for enhanced photoelectrochemical water oxidation

2018 ◽  
Vol 54 (44) ◽  
pp. 5570-5573 ◽  
Author(s):  
Gisang Park ◽  
Joon Yong Park ◽  
Jong Hyeok Seo ◽  
Kyung Hee Oh ◽  
Ahyeon Ma ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Photoelectrochemical Activity ◽  
Sulfite Oxidation ◽  
Ultrasonic Assisted ◽  
Photoelectrochemical Water Oxidation

A pinhole-free BiVO4 electrode showed highly improved photoelectrochemical activity for both sulfite oxidation and water oxidation.

scholarly journals Comparison of Photoelectrochemical Current in Amorphous and Crystalline Anodized TiO2 Nanotube Electrodes

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Candy C. Mercado ◽  
Michael Eric L. Lubrin ◽  
Hazel Anne J. Hernandez ◽  
Reynaldo A. Carubio
Keyword(s):  
Low Temperature ◽  
Annealing Temperature ◽  
Pore Diameter ◽  
Low Voltage ◽  
Tube Length ◽  
Photoelectrochemical Performance ◽  
Amorphous Titania ◽  
Photoelectrochemical Response ◽  
And Performance ◽  
Photocatalytic Applications

The interest in TiO2 nanotubes has resulted in a lot of studies including the effects of various parameters on the properties and performance for different applications. This study investigated the effect of anodization at a low temperature on the properties and photoelectrochemical performance. The effects of varied anodization settings on morphology, crystallinity, and PEC response were studied. Low-temperature anodization resulted in smaller pore diameter and shorter tube length. Annealing temperature affected the presence of varied phases of TiO2 such as the prominence of anatase and amounts of rutile and amorphous TiO2 at 125°C. To observe photoelectrochemical response, annealing at 450°C is necessary. However, a cathodic response was observed for TiO2 nanotubes synthesized with low voltage at low temperature. Hence, amorphous titania nanotubes annealed at 125°C with thickness achieved in the anodization can be a potential material used for photocatalytic applications due to its determined cathodic photoelectrochemical response.

Metastable Defect Distributions in CIGS Solar Cells and Their Impact on Device Efficiency

2007 ◽  
Vol 1012 ◽  
Author(s):  
Malgorzata Igalson
Keyword(s):  
Carrier Transport ◽  
Theoretical Calculations ◽  
Electrical Characteristics ◽  
Current Voltage ◽  
Device Efficiency ◽  
Current Voltage Characteristics ◽  
Cigs Solar Cells ◽  
Metastable Effects ◽  
The Impact ◽  
Metastable Defect

AbstractMetastabilities in the electrical characteristics of CIGS devices are commonly observed phenomena originating from persistent changes of shallow and deep levels distributions within the absorber. We examine characteristic changes induced by voltage bias and light together with their relaxation behavior and interpret them as the consequences of a negative-U type of centers predicted by theoretical calculations of Lany and Zunger. It is shown how the properties of these centers justify a model of p+ layer explaining specific features of light and dark current-voltage characteristics. The discussion showing the impact of various charge distributions on carrier transport is presented. The arguments are provided, that centers responsible for metastable effects are also to blame for majority of photovoltaic losses exhibited in various devices.

Ultrathin CoOx nanolayers derived from polyoxometalate for enhanced photoelectrochemical performance of hematite photoanodes

2019 ◽  
Vol 7 (11) ◽  
pp. 6294-6303 ◽  
Author(s):  
Xiaohu Cao ◽  
Yifan Wang ◽  
Junqi Lin ◽  
Yong Ding
Keyword(s):  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Surface States ◽  
Photoelectrochemical Performance

A CoOx nanolayer derived from Co8POM by photodeposition effectively passivates the surface states of hematite, thereby improving the water oxidation kinetics.

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