scholarly journals Photoactive Tungsten-Oxide Nanomaterials for Water-Splitting

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1871
Author(s):  
Yerkin Shabdan ◽  
Aiymkul Markhabayeva ◽  
Nurlan Bakranov ◽  
Nurxat Nuraje
Keyword(s):  
Tungsten Oxide ◽  
Water Splitting ◽  
Diffusion Length ◽  
Photogenerated Electron ◽  
Photoelectrochemical Cell ◽  
High Electron ◽  
Applied Bias ◽  
Electron Hole ◽  
Research Directions ◽  
Photocatalytic Applications

This review focuses on tungsten oxide (WO3) and its nanocomposites as photoactive nanomaterials for photoelectrochemical cell (PEC) applications since it possesses exceptional properties such as photostability, high electron mobility (~12 cm2 V−1 s−1) and a long hole-diffusion length (~150 nm). Although WO3 has demonstrated oxygen-evolution capability in PEC, further increase of its PEC efficiency is limited by high recombination rate of photogenerated electron/hole carriers and slow charge transfer at the liquid–solid interface. To further increase the PEC efficiency of the WO3 photocatalyst, designing WO3 nanocomposites via surface–interface engineering and doping would be a great strategy to enhance the PEC performance via improving charge separation. This review starts with the basic principle of water-splitting and physical chemistry properties of WO3, that extends to various strategies to produce binary/ternary nanocomposites for PEC, particulate photocatalysts, Z-schemes and tandem-cell applications. The effect of PEC crystalline structure and nanomorphologies on efficiency are included. For both binary and ternary WO3 nanocomposite systems, the PEC performance under different conditions—including synthesis approaches, various electrolytes, morphologies and applied bias—are summarized. At the end of the review, a conclusion and outlook section concluded the WO3 photocatalyst-based system with an overview of WO3 and their nanocomposites for photocatalytic applications and provided the readers with potential research directions.

scholarly journals A molecular tandem cell for efficient solar water splitting

2020 ◽  
Vol 117 (24) ◽  
pp. 13256-13260 ◽  
Author(s):  
Degao Wang ◽  
Jun Hu ◽  
Benjamin D. Sherman ◽  
Matthew V. Sheridan ◽  
Liang Yan ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Photoelectrochemical Cell ◽  
Applied Bias ◽  
Tandem Cell ◽  
Solar Water Splitting ◽  
Dye Sensitized ◽  
Solar Conversion ◽  
Artificial Photosynthetic ◽  
Natural Photosynthesis

Artificial photosynthesis provides a way to store solar energy in chemical bonds. Achieving water splitting without an applied external potential bias provides the key to artificial photosynthetic devices. We describe here a tandem photoelectrochemical cell design that combines a dye-sensitized photoelectrosynthesis cell (DSPEC) and an organic solar cell (OSC) in a photoanode for water oxidation. When combined with a Pt electrode for H2evolution, the electrode becomes part of a combined electrochemical cell for water splitting, 2H2O → O2+ 2H2, by increasing the voltage of the photoanode sufficiently to drive bias-free reduction of H+to H2. The combined electrode gave a 1.5% solar conversion efficiency for water splitting with no external applied bias, providing a mimic for the tandem cell configuration of PSII in natural photosynthesis. The electrode provided sustained water splitting in the molecular photoelectrode with sustained photocurrent densities of 1.24 mA/cm2for 1 h under 1-sun illumination with no applied bias.

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 Preparation, Characterization, and Photocatalytic Applications of MWCNTs/TiO2Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ahmed M. Kamil ◽  
Falah H. Hussein ◽  
Ahmed F. Halbus ◽  
Detlef W. Bahnemann
Keyword(s):  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Multiwall Carbon Nanotubes ◽  
Photogenerated Electron ◽  
Drying Process ◽  
Electron Hole ◽  
Activity Performance ◽  
Photocatalytic Applications ◽  
Multiwall Carbon

The multiwall carbon nanotubes (MWCNTs)/titanium dioxide (P25) composite in different ratios was prepared using simple evaporation and drying process. The composite was characterized by Raman spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of this composite was investigated using degradation of the Bismarck brown R dye (BBR). An optimal MWCNTs/TiO2ratio of 0.5% (w/w) was found to achieve the maximum rate of BBR degradation. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO2. The enhancement in photocatalytic activity performance of the MWCNTs/P25 composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNTs act as a dispersing support to control the morphology of TiO2particles in the MWCNTs/TiO2composite.

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 Advanced Photocatalytic Materials

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 821 ◽  
Author(s):  
Vlassis Likodimos
Keyword(s):  
Rational Design ◽  
Photogenerated Electron ◽  
Photoelectrochemical Cells ◽  
Original Research ◽  
Fuel Production ◽  
Electron Hole ◽  
Volatile Organic ◽  
Photocatalytic Applications ◽  
Hole Recombination ◽  
Photocatalytic Materials

Semiconductor photocatalysts have attracted a great amount of multidiscipline research due to their distinctive potential for solar-to-chemical-energy conversion applications, ranging from water and air purification to hydrogen and chemical fuel production. This unique diversity of photoinduced applications has spurred major research efforts on the rational design and development of photocatalytic materials with tailored structural, morphological, and optoelectronic properties in order to promote solar light harvesting and alleviate photogenerated electron-hole recombination and the concomitant low quantum efficiency. This book presents a collection of original research articles on advanced photocatalytic materials synthesized by novel fabrication approaches and/or appropriate modifications that improve their performance for target photocatalytic applications such as water (cyanobacterial toxins, antibiotics, phenols, and dyes) and air (NOx and volatile organic compounds) pollutant degradation, hydrogen evolution, and hydrogen peroxide production by photoelectrochemical cells.

Cooperation effect of heterojunction and co-catalyst in BiVO4/Bi2S3/NiOOH photoanode for improving photoelectrochemical performances

2018 ◽  
Vol 42 (24) ◽  
pp. 19415-19422 ◽  
Author(s):  
Jindong Wei ◽  
Cailou Zhou ◽  
Ying Xin ◽  
Xifei Li ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Water Splitting ◽  
Light Absorption ◽  
Surface Reaction ◽  
Photogenerated Electron ◽  
Photoelectrochemical Water Splitting ◽  
Electron Hole ◽  
Co Catalyst ◽  
Surface Reaction Kinetics

The separation and transport of photogenerated electron–hole pairs as well as wider light absorption and surface reaction kinetics are the main limitations in photoelectrochemical water splitting.

Metal Tungstate Based Nanocomposites for Environmental Applications: Photocatalysis Mini-Review

2020 ◽  
Vol 18 (12) ◽  
pp. 853-860
Author(s):  
Mohamed Jaffer Sadiq Mohamed
Keyword(s):  
Photogenerated Electron ◽  
Surface Region ◽  
Electron Hole ◽  
Light Reaction ◽  
Natural Toxins ◽  
Metal Tungstate ◽  
Treatment Measures ◽  
Reaction Capacity ◽  
Photocatalytic Applications ◽  
Hole Recombination

Photocatalysis is viewed as perhaps the best-progressed treatment measures in eliminating numerous dangerous natural toxins from wastewater. It enjoys numerous benefits, however some downsides are: (i) Fast photogenerated electron–hole recombination productivity, (ii) they restricted noticeable light reaction capacity, (iii) low specific surface region, and (iv) the expense of reagents utilization. To improve the economy of the process, it is likewise needed to expand the catalyst’s effectiveness. Consequently, there is an extraordinary requirement for the improvement of elite catalysts. This mini-review survey addresses the basics and uses of photocatalytic materials on metal tungstate-based nanocomposites. The mini-review shows how metal tungstate-based nanocom-posites can help take care of ecological issues. This mini-review also expected survey gives outlines, synthesis, characterizations, and exploration discoveries in the field of metal tungstate-based nanocomposites for photocatalytic applications in the future examination.

A correlation of CL emissions from Penrith sandstone with elemental distributions obtained by simultaneous SEM-CL and EDS analysis

1995 ◽  
Vol 53 ◽  
pp. 392-393
Author(s):  
Paul J. Wright
Keyword(s):  
Optical Microscope ◽  
Electron Gun ◽  
High Electron ◽  
Collection System ◽  
Electron Hole ◽  
Depositional Processes ◽  
Eds Analysis ◽  
Distribution Mapping ◽  
Backscattered Electron ◽  
Electron Imaging

Most industrial and academic geologists are familiar with the beautiful red and orange cathodoluminescence colours produced by carbonate minerals in an optical microscope with a cold cathode electron gun attached. The cement stratigraphies interpreted from colour photographs have been widely used to determine the post depositional processes which have modified sedimentary rock textures.However to study quartzose materials high electron densities and kV's are necessary to stimulate sufficient emission. A scanning electron microscope with an optical collection system and monochromator provides an adequate tool and gives the advantage of providing secondary and backscattered electron imaging as well as elemental analysis and distribution mapping via standard EDS/WDS facilities.It has been known that the incorporation of many elements modify the characteristics of the CL emissions from geological materials. They do this by taking up positions between the valence and conduction band thus providing sites to assist in the recombination of electron hole pairs.

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>

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