scholarly journals Regulating Electron-Hole Separation to Promote the Photocatalytic Property of BiOBr<sub>1&#8722x</sub>I<sub>x</sub>/BiOBr Local Distorted Hierarchical Microspheres

2021 ◽  
Vol 10 (02) ◽  
pp. 36-55
Author(s):  
Rui Cheng ◽  
Yan Zhang ◽  
Yanhua Peng ◽  
Xiaolong Yang ◽  
Jianqiang Yu ◽  
...  
Keyword(s):  
Photocatalytic Property ◽  
Electron Hole ◽  
Hierarchical Microspheres

Preparation and Photocatalytic Property of WO3-TiO2 /Ti Ceramic Film via Anodic Oxidation Treatment

2008 ◽  
Vol 368-372 ◽  
pp. 1500-1502 ◽  
Author(s):  
Yan Li Jiang ◽  
Hui Ling Liu ◽  
Zhao Hua Jiang ◽  
Zhong Ping Yao
Keyword(s):  
Visible Light ◽  
Anodic Oxidation ◽  
Rhodamine B ◽  
Recombination Rate ◽  
Visible Region ◽  
Photocatalytic Property ◽  
Electron Hole ◽  
Ceramic Film ◽  
High Efficient ◽  
Anodic Oxidation Treatment

The high efficient WO3-TiO2/Ti ceramic film was prepared on the surface of titanium by the approach of anodic oxidation in order to make the absorbable spectrum of catalyst spread to the visible region and restrain the high recombination rate of electron-hole pairs during photoreaction. The surface morphology and the distribution of elements were studied with scanning electron microscopy and energy dispersive spectroscopy. The phase composition of the films was investigated with XRD. The results showed that the main components in the coating were WO3, rutile TiO2 and anatase TiO2. The compound WO3-TiO2/Ti ceramic film enlarged the range of the reacting visible light and increased the absorbing intensity. The rhodamine B was successfully photodegraded under visible light irradiation by WO3-TiO2/Ti catalyst films. It was found that the highest degradation rate of rhodamine B was achieved through an optimal W dosage of 4.2 %(wt %) in WO3-TiO2/Ti ceramic film. It was also confirmed that the recombination rate of electron-hole pairs in WO3-TiO2/Ti ceramic film declined due to the existence of WO3 in TiO2/Ti ceramic film.

Synthesis of g-C3N4/CuS Heterojunction with Enhanced Photocatalytic Activity Under Visible-Light

2020 ◽  
Vol 20 (9) ◽  
pp. 5896-5905
Author(s):  
Fan Wang ◽  
Qingru Zeng ◽  
Jinping Tang ◽  
Liang Peng ◽  
Jihai Shao ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Separation Efficiency ◽  
Photocatalytic Property ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Electron Hole ◽  
Photocatalytic System ◽  
Composite Photocatalysts ◽  
The Stability

Novel g-C3N4/CuS hybrid photocatalysts were synthesized successfully via a facile hydrothermal method. Characterization results of the photocatalysts showed that especial heterostructure had formed between g-C3N4 and CuS, and possess suitable matched band potential. The composite photocatalysts displayed strong UV-visible light absorption ability in the range from 200 to 800 nm. Photocatalytic performance of the photocatalysts were evaluated via photooxidation of methyl orange (MO) under visible-light irradiation. Hybrid photocatalysts showed better photocatalytic properties than that of pure g-C3N4 or CuS. The 60% g-C3N4/CuS sample proved the supreme photocatalytic property. The integrated g-C3N4 and CuS heterojunction elevated the separation efficiency of photogenerated electron–hole pairs, and increased the photo-decoloration efficiency of MO under visible-light irradiation. A four-cycle repeatability experiment was carried out to investigate the stability of hybrid photocatalysts in the photocatalyst reaction. Radical capture experiments proved that photogenerated e−, h+ and .OH were responsible for MO photo-decoloration. In addition, the potential mechanism of the photocatalytic system g-C3N4/CuS+H2O2+vis are presented.

scholarly journals Insight into the Contributions of Surface Oxygen Vacancies on the Promoted Photocatalytic Property of Nanoceria

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1168
Author(s):  
Yuanpei Lan ◽  
Xuewen Xia ◽  
Junqi Li ◽  
Xisong Mao ◽  
Chaoyi Chen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Oxygen Vacancies ◽  
Separation Efficiency ◽  
Photocatalytic Property ◽  
Pure Hydrogen ◽  
Photogenerated Carrier ◽  
Surface Oxygen ◽  
Photoluminescence Spectra ◽  
Electron Hole ◽  
Insight Into

Oxygen vacancies (OVs) have critical effects on the photoelectric characterizations and photocatalytic activity of nanoceria, but the contributions of surface OVs on the promoted photocatalytic properties are not clear yet. In this work, we synthesized ceria nanopolyhedron (P-CeO2), ceria nanocube (C-CeO2) and ceria nanorod (R-CeO2), respectively, and annealed them at 600 °C in air, 30%, 60% or pure H2. After annealing, the surface OVs concentration of ceria elevates with the rising of H2 concentration. Photocatalytic activity of annealed ceria is promoted with the increasing of surface OVs, the methylene blue photodegradation ratio with pure hydrogen annealed of P-CeO2, C-CeO2 or R-CeO2 is 93.82%, 85.15% and 90.09%, respectively. Band gap of annealed ceria expands first and then tends to narrow slightly with the rising of surface OVs, while the valence band (VB) and conductive band (CB) of annealed ceria changed slightly. Both of photoluminescence spectra and photocurrent results indicate that the separation efficiency of photoinduced electron-hole pairs is significantly enhanced with the increasing of the surface OVs concentration. The notable weakened recombination of photogenerated carrier is suggested to attribute a momentous contribution on the enhanced photocatalytic activity of ceria which contains surface OVs.

Hydrothermal Synthesis and Photocatalytic Property of CdLa2S4 Hierarchical Microspheres

2014 ◽  
Vol 556-562 ◽  
pp. 362-365 ◽  
Author(s):  
Guang Jian Xing ◽  
Hong Li Guo ◽  
Peng Li ◽  
Guang Ming Wu
Keyword(s):  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Photocatalytic Property ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Hierarchical Microspheres ◽  
Structure Morphology ◽  
Scanning Electron

In this study, CdLa2S4hierarchical microspheres have been successfully synthesized through a hydrothermal method without any surfactants or templates. The crystal structure, morphology, and optical properties of the products were characterized by X-ray diffraction, scanning electron microscopy, and UV-vis diffuse reflectance spectroscopy. The results showed that the reaction time affects the structure and morphology of the CdLa2S4products. Finally, the CdLa2S4microspheres showed perfect photocatalytic properties for the degradation of the methyl orange solutions.

scholarly journals PHOTOCATALYTIC EFFICIENCY OF TiO2 IN BIOTEMPLATES FORM IN THE DECOLORATION OF ORGANIC DYE AND INHIBITION OF E. COLI GROWTH

2016 ◽  
Vol 12 (3) ◽  
pp. 4247-4255 ◽  
Author(s):  
Siara Silvestri
Keyword(s):  
Phase Transition ◽  
Atmospheric Oxygen ◽  
Photocatalytic Property ◽  
Titanium Isopropoxide ◽  
Area Measurement ◽  
Electron Hole ◽  
E Coli ◽  
Inhibition Of Growth ◽  
Bet Method ◽  
Electron Hole Pair

Anatase TiO2 is widely used for pollutant degradation due to its photocatalytic property. Exposure of the surface to UV radiation (sunlight or artificial) generates an electron-hole pair that is responsible for the formation of free radicals such as O2•−in the presence of atmospheric oxygen and HO• in the presence of water. Biomorphic TiO2 plates were produced by infiltration of paper with titanium isopropoxide (TTiP) solution followed by hydrolysis in NH4OH and calcination at temperatures up to 600-1000 ºC, as a new way of fixing TiO2 with the aim of delaying the phase transition from anatase (photoactive) to rutile (inactive). In order to study the effect of addition of zirconia as a dopant on the microstructure and the phase transition from anatase to rutile, the same procedure was used, but with the addition of 5% (m/m) of ZrO(NO3)2 to TTiP. The biomorphic materials were characterized by XRD, specific surface area measurement (using the BET method), EPR, and SEM. Their photocatalytic efficiencies were evaluated in the decoloration of Orange II dye and the inhibition of growth of E. coli bioluminescent bacteria. Using 5% Zr-doped TTiP, with calcination at 800 ºC, bacterial growth was reduced by 23% after 180 minutes, and 70% dye decoloration was achieved in30 hours.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

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.

On-line image readout in CTEM

1994 ◽  
Vol 52 ◽  
pp. 400-401
Author(s):  
K.-H. Herrmann ◽  
W. D. Rau ◽  
R. Sikeler
Keyword(s):  
Primary Electron ◽  
Digital Information ◽  
Electron Hole ◽  
Detection Technology ◽  
Long Time ◽  
On Line ◽  
Electron Image ◽  
Optical Transfer ◽  
Detection Quantum Efficiency ◽  
Technical Solutions

Quantitative recording of electron patterns and their rapid conversion into digital information is an outstanding goal which the photoplate fails to solve satisfactorily. For a long time, LLL-TV cameras have been used for EM adjustment but due to their inferior pixel number they were never a real alternative to the photoplate. This situation has changed with the availability of scientific grade slow-scan charged coupled devices (CCD) with pixel numbers exceeding 106, photometric accuracy and, by Peltier cooling, both excellent storage and noise figures previously inaccessible in image detection technology. Again the electron image is converted into a photon image fed to the CCD by some light optical transfer link. Subsequently, some technical solutions are discussed using the detection quantum efficiency (DQE), resolution, pixel number and exposure range as figures of merit.A key quantity is the number of electron-hole pairs released in the CCD sensor by a single primary electron (PE) which can be estimated from the energy deposit ΔE in the scintillator,

Nanostructure of semiconductor quantum dots in a borosilicate glass matrix by complementary use of HREM and AEM

1990 ◽  
Vol 48 (4) ◽  
pp. 728-729
Author(s):  
M.J. Kim ◽  
L.C. Liu ◽  
S.H. Risbud ◽  
R.W. Carpenter
Keyword(s):  
Quantum Dots ◽  
Borosilicate Glass ◽  
Glass Matrix ◽  
Optical Switching ◽  
Response Times ◽  
Fast Response ◽  
Processing Technique ◽  
Internal Stresses ◽  
Electron Hole ◽  
Spatial Dimensions

When the size of a semiconductor is reduced by an appropriate materials processing technique to a dimension less than about twice the radius of an exciton in the bulk crystal, the band like structure of the semiconductor gives way to discrete molecular orbital electronic states. Clusters of semiconductors in a size regime lower than 2R {where R is the exciton Bohr radius; e.g. 3 nm for CdS and 7.3 nm for CdTe) are called Quantum Dots (QD) because they confine optically excited electron- hole pairs (excitons) in all three spatial dimensions. Structures based on QD are of great interest because of fast response times and non-linearity in optical switching applications.In this paper we report the first HREM analysis of the size and structure of CdTe and CdS QD formed by precipitation from a modified borosilicate glass matrix. The glass melts were quenched by pouring on brass plates, and then annealed to relieve internal stresses. QD precipitate particles were formed during subsequent "striking" heat treatments above the glass crystallization temperature, which was determined by differential thermal analysis.

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

Sign in / Sign up

Export Citation Format

Share Document