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.

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 Construction of NiMoS3/BC heterostructure photoanodes and optimization of light scattering to improve the photovoltaic performance of dye sensitized solar cells (DSSCs)

2021 ◽  
Author(s):  
T Sumathi ◽  
Sonia A Fredricka ◽  
G Deepa
Keyword(s):  
Solar Cells ◽  
Large Scale ◽  
Photovoltaic Performance ◽  
Dye Sensitized Solar Cells ◽  
Photocurrent Density ◽  
Electron Hole ◽  
Dye Sensitized ◽  
Electron Hole Pair ◽  
Conversion Efficiencies ◽  
Sensitized Solar Cells

Abstract In the last two decades, dye sensitized solar cells (DSSCs) have gotten a lot of attention from researchers and have progressed quickly. To promote commercialization and large-scale application of DSSCs, their efficiency should be increased. This paper details significant advancements in advanced NiMoS3/BC nanocomposites for improving photoanodes and DSSC conversion efficiencies. The fabricated electrode samples were characterized by XRD, SEM, TEM, Raman, UV, PL and BET to explore the structural, morphological and optical properties. A significant reduction band gap with enhanced light absorption and rapid prevention of electron hole pair was explored by UV-DRS and PL studies. The photocurrent density-voltage (J-V) and IPCE characteristics were analyzed for assembled solar cell. The NiMoS3/BC (NMSC5) nanocomposite DSSC showed a PCE of 8.85%, far higher than that of the NiMoS3 (2.45%) and a PCE value equivalent to Pt CE (4.79 %). The enhanced PCE of the proposed electrodes are also discussed in scientifically.

scholarly journals Photocatalytic water splitting by N-TiO2 on MgO (111) with exceptional quantum efficiencies at elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yiyang Li ◽  
Yung-Kang Peng ◽  
Liangsheng Hu ◽  
Jianwei Zheng ◽  
Dharmalingam Prabhakaran ◽  
...  
Keyword(s):  
Water Splitting ◽  
Elevated Temperatures ◽  
Practical Method ◽  
Charge Carriers ◽  
Molar Ratio ◽  
Electron Hole ◽  
Photocatalytic Water Splitting ◽  
The Past ◽  
Electron Hole Pair ◽  
Electric Field Polarization

Abstract Photocatalytic water splitting is attracting enormous interest for the storage of solar energy but no practical method has yet been identified. In the past decades, various systems have been developed but most of them suffer from low activities, a narrow range of absorption and poor quantum efficiencies (Q.E.) due to fast recombination of charge carriers. Here we report a dramatic suppression of electron-hole pair recombination on the surface of N-doped TiO2 based nanocatalysts under enhanced concentrations of H+ and OH−, and local electric field polarization of a MgO (111) support during photolysis of water at elevated temperatures. Thus, a broad optical absorption is seen, producing O2 and H2 in a 1:2 molar ratio with a H2 evolution rate of over 11,000 μmol g−1 h−1 without any sacrificial reagents at 270 °C. An exceptional range of Q.E. from 81.8% at 437 nm to 3.2% at 1000 nm is also reported.

Behavior of Photogenerated Electron–Hole Pair for Water Splitting on TiO2(110)

2018 ◽  
Vol 122 (40) ◽  
pp. 22930-22938 ◽  
Author(s):  
Fan Jin ◽  
Min Wei ◽  
Tingwei Chen ◽  
Huizhong Ma ◽  
Guokui Liu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photogenerated Electron ◽  
Hole Pair ◽  
Electron Hole ◽  
Electron Hole Pair

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 Enhanced Photoelectrocatalytic Performance of TiO2 Nanorods in Photoelectrochemical Water Splitting Cell by Using an Alcoholic Sacrificial Agent

2019 ◽  
Author(s):  
Armin Hariri ◽  
Neda Gilani ◽  
Javad Vahabzadeh Pasikhani
Keyword(s):  
Water Splitting ◽  
Hydrogen Generation ◽  
Hole Pair ◽  
Tio2 Nanorods ◽  
Generation Rate ◽  
Hydrogen Atoms ◽  
Electron Hole ◽  
Anodic Chamber ◽  
Electron Hole Pair ◽  
Sacrificial Agent

Photoelectrocatalytic water splitting by using various TiO2 nanostructures is a promising approach to generate hydrogen without harmful byproducts. However, their effective performance is restricted by some drawbacks such as high rapid electron-hole pair recombination and backward reaction producing H2O. Thus in this study, the probability of enhancing hydrogen generation rate by adding methanol as a sacrificial agent to the anodic chamber of a two-compartment photoelectrochemical cell is investigated. Herein, one-dimensional elongated TiO2 nanorods that were fabricated via a facile one-pot hydrothermal method are utilized as potent photoanode. Voltammetric characterizations confirm that addition of alcoholic sacrificial agent has a significant effect on photoelectrochemical properties of TiO2 nanorods which by adding 10 wt% of methanol, the photocurrent density and photoconversion efficiency increased from 0.8mA.cm-2 to 1.5mA.cm-2 and from 0.28% to 0.45%, respectively. The results of photoelectrocatalytic water splitting indicated that the hydrogen generation rate in the presence of methanol was about 1.2 times higher than that from pure water splitting. These enhancements can be attributed to the key role of methanol. Methanol molecules not only inhibit the electron-hole pair recombination but also accelerate the hydrogen generation rate by sharing their hydrogen atoms.

scholarly journals Surface photosensitization of ZnO by ZnS to enhance the photodegradation efficiency for organic pollutants

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Sunaina ◽  
Sapna Devi ◽  
S. T. Nishanthi ◽  
S. K. Mehta ◽  
A. K. Ganguli ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Organic Dyes ◽  
Light Exposure ◽  
Low Cost ◽  
Visible Region ◽  
Zns Nanoparticles ◽  
Electron Hole ◽  
Photodegradation Efficiency ◽  
Electron Hole Pair ◽  
Scalable Synthesis

AbstractIt is challenging to develop a material which has low cost, high activity, good stability and recyclability under light exposure. Apart from these properties, the photocatalyst should also have good visible region absorbance and low electron-hole pair recombination rate. Keeping all this in view, we have designed a simple scalable synthesis of ZnO–ZnS heterostructures for the photocatalytic treatment of industrial waste (p-nitrophenol and methyl orange). The ZnO–ZnS heterostructures are synthesized via a solvent-free route by thermal annealing of solid-state mixture of ZnO and thiourea (a sulphur source) which results in ZnO–ZnS core shell kind of heterostructure formation. The interface formation between the ZnO–ZnS heterostructure favored the band-gap reduction in comparison to the bare ZnO and ZnS nanoparticles. Further, these ZnO–ZnS heterostructures were utilized as a photocatalyst for the degradation of toxic phenolic molecules (p-nitrophenol) and harmful organic dyes (methyl orange) present in the water under the light exposure (> 390 nm).

Ti3C2-MXene/Bismuth Ferrite Nanohybrids for Efficient Degradation of Organic Dye and Colorless Pollutant

2019 ◽  
Author(s):  
Ayesha Tariq ◽  
M. Abdullah Iqbal ◽  
S. Irfan Ali ◽  
Muhammad Z. Iqbal ◽  
Deji Akinwande ◽  
...  
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
Bismuth Ferrite ◽  
Organic Dye ◽  
Two Dimensional ◽  
Electron Hole ◽  
Photocatalytic Application ◽  
Electron Hole Pair ◽  
Pair Generation ◽  
Photocatalytic Applications

<p>Nanohybrids, made up of Bismuth ferrites/Carbon allotropes, are extensively used in photocatalytic applications nowadays. Our work proposes a nanohybrid system composed of Bismuth ferrite nanoparticles with two-dimensional (2D) MXene sheets namely, the BiFeO<sub>3</sub> (BFO)/Ti<sub>3</sub>C<sub>2</sub> (MXene) nanohybrid for enhanced photocatalytic activity. We have fabricated the BFO/MXene nanohybrid using simple and low cost double solvent solvothermal method. The SEM and TEM images show that the BFO nanoparticles were attached onto the MXene surface and in the inter-layers of two-dimensional (2D) MXene sheets. The photocatalytic application is tested for the visible light irradiation which showed the highest efficiency among all pure-BFO based photocatalysts, i.e. 100% degradation in 42 min for organic dye (Congo Red) and colorless aqueous pollutant (acetophenone) in 150 min, respectively. The present BFO-based hybrid system exhibited the large surface area of 147 m<sup>2</sup>g<sup>-1</sup>measured via Brunauer-Emmett-Teller (BET) sorption-desorption technique, and is found to be largest among BFO and its derivatives. Also, the photoluminescence (PL) spectra indicate large electron-hole pair generation. Fast and efficient degradation of organic molecules is supported by both factors; larger surface area and lower electron-hole recombination rate. The BFO/MXene nanohybrid presented here is a highly efficient photocatalyst compared to other nanostructures based on pure BiFeO<sub>3</sub> which makes it a promising candidate for many future applications.</p>

Electrical Invasiveness of Grinding and Polishing Silicon Integrated Circuits Down to 1 μm Remaining Silicon Thickness

2016 ◽  
Author(s):  
Robert Chivas ◽  
Scott Silverman ◽  
Michael DiBattista ◽  
Ulrike Kindereit
Keyword(s):  
Integrated Circuits ◽  
Failure Analysis ◽  
Electron Hole ◽  
Analysis Techniques ◽  
Silicon Integrated Circuits ◽  
Electron Hole Pair ◽  
Pair Generation ◽  
Silicon Thickness ◽  
Performance Timing ◽  
Grinding And Polishing

Abstract Anticipating the end of life for IR-based failure analysis techniques, a method of global backside preparation to ultra-thin remaining silicon thickness (RST) has been developed. When the remaining silicon is reduced, some redistribution of stress is expected, possibly altering the performance (timing) of integrated circuits in addition to electron-hole pair generation. In this work, a study of the electrical invasiveness due to grinding and polishing silicon integrated circuits to ultra-thin (&lt; 5 um global, ~ 1 um local) remaining thickness is presented.

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