scholarly journals Photoresponse of Visible Light Active CM-n-TiO2, HM-n-TiO2, CM-n-Fe2O3, and CM-p-WO3towards Water Splitting Reaction

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Yasser A. Shaban ◽  
Shahed U. M. Khan

Photoresponses of visible light active carbon modified titanium oxide (CM-n-TiO2), hydrogen modified titanium oxide (HM-n-TiO2), carbon modified iron oxide (CM-n-Fe2O3), carbon modified tungsten oxide (CM-p-WO3) towards water splitting reaction are reported in this article. Carbon and hydrogen in titanium oxide were found to be responsible for red shift from UV region to visible region which in turn enhanced the photoconversion efficiency by an order of magnitude for water splitting reaction. Photocurrent densities and photoconversion efficiencies of regular n-TiO2and CM-n-TiO2towards water splitting reaction under monochromatic light illumination from a xenon lamp and sunlight were compared and found in reasonable agreement. These oxides were characterized by photocurrent measurements,UV-Visspectra, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD) studies and these results are also reported in this article.

2012 ◽  
Vol 11 (05) ◽  
pp. 1250030 ◽  
Author(s):  
TESHOME ABDO SEGNE ◽  
SIVA RAO TIRUKKOVALLURI ◽  
SUBRAHMANYAM CHALLAPALLI

The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol–gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+ . The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption–desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.


2013 ◽  
Vol 448-453 ◽  
pp. 2946-2949
Author(s):  
Bo Yang ◽  
Min Di Bai

Photocatalytic hydrogen production from water splitting with semiconductor materials has received intense attention due to its potential to address important energy and environmental problems. In this work, we reported the facile preparation of NaInS2 photocatalyst with hierarchical nanostructure using solvothermal method. The as-prepared NaInS2 photocatalyst was extensively characterized with X-ray powder diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. It was found that the as-prepared NaInS2 was composed of numerous interconnected nanoplates with thickness of around 100 nm. Reaction parameters such as the synthesis temperature and duration were found to be crucial for the formation of crystalline NaInS2. Moreover, ethylene glycol played an important role in tuning NaInS2 with hierarchical nanostructure. The as-prepared hierarchical NaInS2 photocatalyst demonstrated strong absorption in the visible region and appreciable activity for the photocatalytic H2 production from water splitting under visible light irradiation (λ > 420 nm).


Author(s):  
Jacob Schneidewind ◽  
Miguel A. Argüello Cordero ◽  
Henrik Junge ◽  
Stefan Lochbrunner ◽  
Matthias Beller

A new mechanism for light-driven water splitting is described, which decreases the reaction's complexity and offers a new way to extend the range of usable wavelengths far into the visible region.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-guo Huang ◽  
Xue-ting Guo ◽  
Bo Wang ◽  
Lin-yang Li ◽  
Mei-xia Zhao ◽  
...  

The undoped and Mo-doped TiO2nanoparticles were synthesized by sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance UV-visible absorption spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue under irradiation of a 500 W xenon lamp and natural solar light outdoor. Effects of calcination temperatures and Mo doping amounts on crystal phase, crystallite size, lattice distortion, and optical properties were investigated. The results showed that most of Mo6+took the place of Ti4+in the crystal lattice of TiO2, which inhibited the growth of crystallite size, suppressed the transformation from anatase to rutile, and led to lattice distortion of TiO2. Mo doping narrowed the band gap (from 3.05 eV of TiO2to 2.73 eV of TiMo0.02O) and efficiently increased the optical absorption in visible region. Mo doping was shown to be an efficient method for degradation of methylene blue under visible light, especially under solar light. When the calcination temperature was 550°C and the Mo doping amount was 2.0%, the Mo-doped TiO2sample exhibited the highest photocatalytic activity.


2018 ◽  
Vol 281 ◽  
pp. 878-884
Author(s):  
Zhi Wei Zhou ◽  
Ling Fang Qiu ◽  
Xiao Bin Qiu ◽  
Shu Wang Duo

In order to enhance hole/electron separation and charge transfer in photocatalysts, the heterostructured g-C3N4/CoAPO-5 hybrids materials were synthesized via a simple grinding method and were investigated using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The optical properties of g-C3N4/CoAPO-5 hybrids materials were measured by ultraviolet-visible diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra and ultraviolet-visible absorption (UV-Vis) spectra. Under visible-light illumination, this work shows the heterogeneous g-C3N4/CoAPO-5 hybrids present a superior photocatalytic activity.


Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2261 ◽  
Author(s):  
Abdul Wafi ◽  
Erzsébet Szabó-Bárdos ◽  
Ottó Horváth ◽  
Mihály Pósfai ◽  
Éva Makó ◽  
...  

Catalysts for visible-light-driven oxidative cleaning processes and antibacterial applications (also in the dark) were developed. In order to extend the photoactivity of titanium dioxide into the visible region, nitrogen-doped TiO2 catalysts with hollow and non-hollow structures were synthesized by co-precipitation (NT-A) and sol–gel (NT-U) methods, respectively. To increase their photocatalytic and antibacterial efficiencies, various amounts of silver were successfully loaded on the surfaces of these catalysts by using a facile photo-deposition technique. Their physical and chemical properties were evaluated by using scanning electron microscopy (SEM), transmission electron microscopy–energy dispersive X-ray spectroscopy (TEM–EDS), Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), and diffuse reflectance spectra (DRS). The photocatalytic performances of the synthesized catalysts were examined in coumarin and 1,4-hydroquinone solutions. The results showed that the hollow structure of NT-A played an important role in obtaining high specific surface area and appreciable photoactivity. In addition, Ag-loading on the surface of non-hollow structured NT-U could double the photocatalytic performance with an optimum Ag concentration of 10−6 mol g−1, while a slight but monotonous decrease was caused in this respect for the hollow surface of NTA upon increasing Ag concentration. Comparing the catalysts with different structures regarding the photocatalytic performance, silverized non-hollow NT-U proved competitive with the hollow NT-A catalyst without Ag-loading for efficient visible-light-driven photocatalytic oxidative degradations. The former one, due to the silver nanoparticles on the catalyst surface, displayed an appreciable antibacterial activity, which was comparable to that of a reference material practically applied for disinfection in polymer coatings.


2020 ◽  
Vol 402 ◽  
pp. 126226 ◽  
Author(s):  
Yanchen Ji ◽  
Ruiqi Yang ◽  
Longwei Wang ◽  
Guoxin Song ◽  
Aizhu Wang ◽  
...  

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 261 ◽  
Author(s):  
Van Nghia Nguyen ◽  
Minh Vuong Nguyen ◽  
Thi Hong Trang Nguyen ◽  
Minh Thuy Doan ◽  
Loan Le Thi Ngoc ◽  
...  

High-stability, high-efficiency, and low-cost solar photoelectrochemical (PEC) water splitting has great potential for hydrogen-energy applications. Here, we report on gold/titanium dioxide (Au/TiO2) nanofiber structures grown directly on a conductive indium tin oxide substrate, and used as photoelectrodes in PEC cells for hydrogen generation. The titanium dioxide nanofibers (TiO2 NFs) are synthesized using electrospinning, and are surface-modified by the deposition of gold nanoparticles (Au NPs) using a simple photoreduction method. The structure and morphology of the materials were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) of the Au NPs was investigated by ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. The PEC properties of the as-prepared photoelectrodes were measured. The obtained photoconversion efficiency of 0.52% under simulated-sunlight illumination by a 150 W xenon lamp of the Au/TiO2 NFs structure with 15 min UV irradiation for Au NP deposition was the highest value from comparable structures. Working photoelectrode stability was tested, and the mechanism of the enhanced PEC performance is discussed.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.


2015 ◽  
Vol 1101 ◽  
pp. 299-302 ◽  
Author(s):  
Hanggara Sudrajat ◽  
Sandhya Babel

A visible light active nitrogen-doped ZnO (N-ZnO) was synthesized using a solvent-free mechanochemical method and applied to degrade methylene blue (MB) dye in aqueous suspension. Results showed that nitrogen doping improved the photocatalytic activity of pristine ZnO by extending its spectral response to visible region. Using 2 g/L of N-ZnO, 98% MB with the initial concentration of 10 mg/L could be degraded within 2 h at pH 7 under 11.3 klux of visible light irradiation. After 6th run, it still exhibited appreciable photocatalytic activity with 94% MB degradation, indicating its high reusability though a simple pretreatment was performed.


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