scholarly journals Multilayer WO3/BiVO4 Photoanodes for Solar-Driven Water Splitting Prepared by RF-Plasma Sputtering

Surfaces ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Matteo Pedroni ◽  
Gian Luca Chiarello ◽  
Espedito Vassallo ◽  
Elena Selli
Keyword(s):  
Water Splitting ◽  
Photocurrent Density ◽  
Rf Plasma ◽  
Back Side ◽  
Time Stability ◽  
Electron Hole ◽  
Plasma Sputtering ◽  
Innermost Layer ◽  
Carrier Separation ◽  
Hole Recombination

A series of WO3, BiVO4 and WO3/BiVO4 heterojunction coatings were deposited on fluorine-doped tin oxide (FTO), by means of reactive radio frequency (RF) plasma (co)sputtering, and tested as photoanodes for water splitting under simulated AM 1.5 G solar light in a three-electrode photoelectrochemical (PEC) cell in a 0.5 M NaSO4 electrolyte solution. The PEC performance and time stability of the heterojunction increases with an increase of the WO3 innermost layer up to 1000 nm. A two-step calcination treatment (600 °C after WO3 deposition followed by 400 °C after BiVO4 deposition) led to a most performing photoanode under back-side irradiation, generating a photocurrent density of 1.7 mA cm−2 at 1.4 V vs. SCE (i.e., two-fold and five-fold higher than that generated by individual WO3 and BiVO4 photoanodes, respectively). The incident photon to current efficiency (IPCE) measurements reveal the presence of two activity regions over the heterojunction with respect to WO3 alone: The PEC efficiency increases due to improved charge carrier separation above 450 nm (i.e., below the WO3 excitation energy), while it decreases below 450 nm (i.e., when both semiconductors are excited) due to electron–hole recombination at the interface of the two semiconductors.

scholarly journals Boosting the Activity and Stability of Copper Tungsten Nanoflakes toward Solar Water Oxidation by Iridium-Cobalt Phosphates Modification

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 913
Author(s):  
Chao Li ◽  
Peng Diao
Keyword(s):  
Water Oxidation ◽  
Collection Efficiency ◽  
Potassium Phosphate ◽  
Photocurrent Density ◽  
Charge Transfer Resistance ◽  
Buffer Solution ◽  
Hydrogen Electrode ◽  
Electron Hole ◽  
Transfer Resistance ◽  
Hole Recombination

Severe interfacial electron–hole recombination greatly limits the performance of CuWO4 photoanode towards the photoelectrochemical (PEC) oxygen evolution reaction (OER). Surface modification with an OER cocatalyst can reduce electron–hole recombination and thus improve the PEC OER performance of CuWO4. Herein, we coupled CuWO4 nanoflakes (NFs) with Iridium–cobalt phosphates (IrCo-Pi) and greatly improved the photoactivity of CuWO4. The optimized photocurrent density for CuWO4/IrCo-Pi at 1.23 V vs. reversible hydrogen electrode (RHE) rose to 0.54 mA∙cm−2, a ca. 70% increase over that of bare CuWO4 (0.32 mA∙cm−2). Such improved photoactivity was attributed to the enhanced hole collection efficiency, which resulted from the reduced charge-transfer resistance via IrCo-Pi modification. Moreover, the as-deposited IrCo-Pi layer well coated the inner CuWO4 NFs and effectively prevented the photoinduced corrosion of CuWO4 in neutral potassium phosphate (KPi) buffer solution, eventually leading to a superior stability over the bare CuWO4. The facile preparation of IrCo-Pi and its great improvement in the photoactivity make it possible to design an efficient CuWO4/cocatalyst system towards PEC water oxidation.

Acid Treatment Enables Suppression of Electron-Hole Recombination in Hematite for Photoelectrochemical Water Splitting

2016 ◽  
Vol 128 (10) ◽  
pp. 3464-3468 ◽  
Author(s):  
Yi Yang ◽  
Mark Forster ◽  
Yichuan Ling ◽  
Gongming Wang ◽  
Teng Zhai ◽  
...  
Keyword(s):  
Water Splitting ◽  
Acid Treatment ◽  
Photoelectrochemical Water Splitting ◽  
Electron Hole ◽  
Hole Recombination

Acid Treatment Enables Suppression of Electron-Hole Recombination in Hematite for Photoelectrochemical Water Splitting

2016 ◽  
Vol 55 (10) ◽  
pp. 3403-3407 ◽  
Author(s):  
Yi Yang ◽  
Mark Forster ◽  
Yichuan Ling ◽  
Gongming Wang ◽  
Teng Zhai ◽  
...  
Keyword(s):  
Water Splitting ◽  
Acid Treatment ◽  
Photoelectrochemical Water Splitting ◽  
Electron Hole ◽  
Hole Recombination

scholarly journals Efficient Photoelectrochemical Water Splitting by Tailoring MoS2/CoTe Heterojunction in a Photoelectrochemical Cell

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2341
Author(s):  
Effat Sitara ◽  
Habib Nasir ◽  
Asad Mumtaz ◽  
Muhammad Fahad Ehsan ◽  
Manzar Sohail ◽  
...  
Keyword(s):  
Water Splitting ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Photocurrent Density ◽  
Photoelectrochemical Water Splitting ◽  
Photoelectrochemical Cell ◽  
Electron Hole ◽  
Pair Separation ◽  
Electron Hole Pair ◽  
Electrochemical Impedance Spectroscopic

Solar energy conversion through photoelectrochemical water splitting (PEC) is an upcoming promising technique. MoS2/CoTe heterostructures were successfully prepared and utilized for PEC studies. MoS2 and CoTe were prepared by a hydrothermal method which were then ultrasonicated with wt. % ratios of 1:3, 1:1 and 3:1 to prepare MoS2/CoTe (1:3), MoS2/CoTe (1:1) and MoS2/CoTe (3:1) heterostructure, respectively. The pure materials and heterostructures were characterized by XRD, UV–vis-DRS, SEM, XPS, PL and Raman spectroscopy. Photoelectrochemical measurements were carried out by linear sweep voltammetry and electrochemical impedance spectroscopic measurements. A maximum photocurrent density of 2.791 mA/cm2 was observed for the MoS2/CoTe (1:1) heterojunction which is about 11 times higher than the pristine MoS2. This current density was obtained at an applied bias of 0.62 V vs. Ag/AgCl (1.23 V vs. RHE) under the light intensity of 100 mW/cm2 of AM 1.5G illumination. The enhanced photocurrent density may be attributed to the efficient electron–hole pair separation. The solar to hydrogen conversion efficiency was found to be 0.84% for 1:1 MoS2/CoTe, signifying the efficient formation of the p-n junction. This study offers a novel heterojunction photocatalyst, for PEC water splitting.

scholarly journals A rationally designed two-dimensional MoSe2/Ti2CO2 heterojunction for photocatalytic overall water splitting: simultaneously suppressing electron–hole recombination and photocorrosion

2021 ◽  
Author(s):  
Cen-Feng Fu ◽  
Xingxing Li ◽  
Jinlong Yang
Keyword(s):  
Transition Metal ◽  
Water Splitting ◽  
Rational Design ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Electron Hole ◽  
Photocatalytic Water Splitting ◽  
Overall Water Splitting ◽  
Metal Dichalcogenides ◽  
Hole Recombination

The two challenges of electron–hole recombination and photocorrosion for two-dimensional transition metal dichalcogenides in the application of photocatalytic water splitting are simultaneously suppressed by rational design of heterojunctions.

scholarly journals Back Electron–Hole Recombination in Hematite Photoanodes for Water Splitting

2014 ◽  
Vol 136 (6) ◽  
pp. 2564-2574 ◽  
Author(s):  
Florian Le Formal ◽  
Stephanie R. Pendlebury ◽  
Maurin Cornuz ◽  
S. David Tilley ◽  
Michael Grätzel ◽  
...  
Keyword(s):  
Water Splitting ◽  
Electron Hole ◽  
Hole Recombination

scholarly journals Fabrication of a stable light-activated and p/n type AgVO3/V2O5-TiO2 heterojunction for pollutants removal and photoelectrochemical water splitting

2021 ◽  
Author(s):  
Hai Yu ◽  
Zhang Miao ◽  
Yanfen Wang ◽  
Jianguo Lv ◽  
Lei Yang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photocurrent Density ◽  
Nanorod Arrays ◽  
Electron Hole ◽  
Photodegradation Efficiency ◽  
Conductive Glass ◽  
Electron Hole Pair ◽  
Layer V ◽  
Pollutants Removal ◽  
Efficiency Rate

Abstract In this study, TiO2 nanorod arrays (TiO2) was fabricated and modified with the AgVO3 quantum dots (QDs) decorate on interfacing few-layer V2O5 to form a heterojunction material for removal pollutants and photoelectrochemical (PCE) water splitting. The AgVO3/V2O5-TiO2 nanorod arrays (AgVO3/V2O5-TiO2) synthesized by the secondary hydrothermal method were loaded with conductive glass, which facilitated the formation of one-dimensional (1D) nanorod and p-n junction structures. Through instrumentations, to investigate the structural, morphological, optical, photocatalytic and PCE characteristics of the materials. The TiO2 modified by AgVO3 and V2O5 can significantly improve the visible light optical absorption, the reduce the electron-hole pair binding rate and shorten the band gap (3.07-1.41eV) of TiO2. The resulting photocurrent density (116uA/cm2 ) and photodegradation efficiency (rate constant, k = 0.025min− 1) of AgVO3/V2O5-TiO2 are approximately 20 (6uA/cm2) and 5 times (0.005min− 1) higher than those of bare TiO2, respectively. The AgVO3/V2O5-TiO2 achieved a current density of 10mA at an overpotential of 246.2mV and exhibited excellent oxygen evolution reaction (OER) performance. The systematic PEC experiments concluded that the optimized of the TiO2 interface by AgVO3 and V2O5 could promote the separation and transport of charge carriers.

Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles

1998 ◽  
Vol 536 ◽  
Author(s):  
H. Porteanu ◽  
A. Glozman ◽  
E. Lifshitz ◽  
A. Eychmüller ◽  
H. Weller
Keyword(s):  
Optical Properties ◽  
Magnetic Resonance ◽  
Cds Nanoparticles ◽  
Electron Hole ◽  
Cladding Layer ◽  
Double Beam ◽  
Optically Detected Magnetic Resonance ◽  
Optically Detected ◽  
Cladding Layers ◽  
Hole Recombination

AbstractCdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.

Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling

1999 ◽  
Vol 40 (4-5) ◽  
pp. 123-130 ◽  
Author(s):  
S. Malato ◽  
J. Blanco ◽  
C. Richter ◽  
B. Milow ◽  
M. I. Maldonado
Keyword(s):  
Organic Contaminants ◽  
Toxic Waste ◽  
Experimental Plant ◽  
Electron Hole ◽  
Particulate Suspensions ◽  
Photocatalytic System ◽  
Commercial Pesticide ◽  
Pesticide Container ◽  
By Products ◽  
Hole Recombination

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).

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