Photocatalytic activity of fluorine doped SrTiO3 under the irradiation of UV/solar light: Extended visible light absorption by the bulk lattice F− ions and suppression of photogenerated charge carrier recombination by the surface F− ions

2020 ◽  
Vol 742 ◽  
pp. 137138 ◽  
Author(s):  
B.G. Anitha ◽  
L. Gomathi Devi
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Visible Light ◽  
Light Absorption ◽  
Solar Light ◽  
Photogenerated Charge Carrier ◽  
Visible Light Absorption ◽  
Carrier Recombination ◽  
Charge Carrier Recombination

Few-Layered MoS2 Nanoparticles Loaded TiO2 Nanosheets with Exposed {001} Facets for Enhanced Photocatalytic Activity

NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850129 ◽  
Author(s):  
Chujun Chen ◽  
Xia Xin ◽  
Jinniu Zhang ◽  
Gang Li ◽  
Yafeng Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Visible Light ◽  
Recombination Rate ◽  
Active Species ◽  
Molar Ratio ◽  
Carrier Recombination ◽  
Tio2 Nanosheets ◽  
Photocatalytic Activities ◽  
Charge Carrier Recombination

To improve the high charge carrier recombination rate and low visible light absorption of {001} facets exposed TiO2 [TiO2(001)] nanosheets, few-layered MoS2 nanoparticles were loaded on the surfaces of TiO2(001) nanosheets by a simple photodeposition method. The photocatalytic activities towards Rhodamine B (RhB) were investigated. The results showed that the MoS2–TiO2(001) nanocomposites exhibited much enhanced photocatalytic activities compared with the pure TiO2(001) nanosheets. At an optimal Mo/Ti molar ratio of 25%, the MoS2–TiO2(001) nanocomposites displayed the highest photocatalytic activity, which took only 30[Formula: see text]min to degrade 50[Formula: see text]mL of RhB (50[Formula: see text]mg/L). The active species in the degradation reaction were determined to be h[Formula: see text] and [Formula: see text]OH according to the free radical trapping experiments. The reduced charge carrier recombination rate, enhanced visible light utilization and increased surface areas contributed to the enhanced photocatalytic performances of the 25% MoS2–TiO2(001) nanocomposites.

Impact of Loading of RuO2 Co-Catalyst on Photocatalytic Activity of PbTiO3 Nanorods for Hydrogen Production Under Visible Light

2019 ◽  
Vol 11 (11) ◽  
pp. 1540-1546
Author(s):  
Maha Alhaddad ◽  
Reda M. Mohamed
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Visible Light ◽  
High Surface ◽  
Weight Percent ◽  
Light Illumination ◽  
Hydrothermal Route ◽  
Carrier Recombination ◽  
Production Of Hydrogen ◽  
Charge Carrier Recombination

The split of charge carriers is an essential point that raises the rate of hydrogen evolution in the reaction of water splitting. The avoidance of charge carrier recombination can be attained by deposition of co-catalysts onto the surface of semiconductor materials. In this work, PbTiO3 nanorods were prepared using hydrothermal route in the presence of polyvinylpyrrolidone as a surfactant. Finally, PbTiO3 nanorods were decorated by RuO2 nanoparticles and the weight percent of RuO2 changed from 0.5 to 2.0 wt%. PbTiO3 nanorods and RuO2–PbTiO3 nanocomposites were investigated for their production of hydrogen under visible light illumination in the presence of glycerol as a scavenger. The outcomes recorded that the photocatalytic activity of PbTiO3 nanorods was improved by RuO2 nanoparticles decoration. The content of RuO2 nanoparticles had an important effect on the photocatalytic activity of PbTiO3 nanorods. The best weight percent of decorated RuO2 was 1.5 wt%, which improved photocatalytic activity of PbTiO3 nanorods by about 6 times. Moreover, the photocatalytic activity of 1.5 wt% RuO2–PbTiO3 nanocomposites was almost stable for five times. The enlargement of photocatalytic activity of PbTiO3 nanorods by RuO2 decoration was due to high surface area, small bandgap and avoidance of charge carrier recombination.

Controllable synthesis of a 3D ZnS@MoO3 heterojunction via a hydrothermal method towards efficient NO purification under visible light

CrystEngComm ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Ziyang Guo ◽  
Wangchen Huo ◽  
Tong Cao ◽  
Fangzheng Fan ◽  
Guangxu Ge ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Light Absorption ◽  
Interface Reaction ◽  
Photocatalytic Efficiency ◽  
Controllable Synthesis ◽  
Carrier Recombination ◽  
Charge Carrier Recombination

Heterojunctions can deliver superior photocatalytic efficiency via modulating the surface-interface reaction, enhancing light absorption and hindering charge carrier recombination.

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

scholarly journals Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

2021 ◽  
Author(s):  
Mehala Kunnamareddy ◽  
Ranjith Rajendran ◽  
Megala Sivagnanam ◽  
Ramesh Rajendran ◽  
Barathi Diravidamani
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Fourier Transforms ◽  
Phase Particle ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Visible Light Absorption

AbstractIn this work, Nickel (Ni) and sulfur (S) codoped TiO2 nanoparticles were prepared by a sol-gel technique. The as-prepared catalyst was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), FT-Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS) for investigating crystal structure, crystal phase, particle size and bandgap energy of these samples. The photocatalytic performances of all the prepared catalysts have been investigated for the degradation of methylene blue (MB) under visible light irradiation. It was noticed that Ni-S codoped TiO2(Ni-S/TiO2) nanoparticles exhibited much higher photocatalytic activity compared with pure, Ni and S doped TiO2 due to higher visible light absorption and probable decrease in the recombination of photo-generated charges. It was decided that the great visible light absorption was created for codoped TiO2 by the formation of impurity energy states near both the edges of the collection, which works as trapping sites for both the photogenerated charges to decrease the recombination process.

Visible Light Absorption Characteristics of M-Nitrogen (M= Mn, Fe, Co, Ni, Cu) Co-Doped Monodisperse TiO2 Microparticles

2015 ◽  
Vol 1806 ◽  
pp. 19-24 ◽  
Author(s):  
John E. Mathis
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metals ◽  
Visible Light ◽  
Light Absorption ◽  
Sol Gel ◽  
Percent Level ◽  
Wide Distribution ◽  
Electromagnetic Spectrum ◽  
Visible Light Absorption ◽  
Co Doping

ABSTRACTThere is great interest in improving TiO2’s photocatalytic activity in the visible portion of electromagnetic spectrum. Recent work has shown that co-doping mesoporous TiO2 microparticles with a transition metal and nitrogen, hereby designated as (M,N) TiO2, significantly increases its visible light absorption. However, the hydrothermal method used to produce the microparticles creates a wide distribution in the size of the microparticles, which could affect the absorption properties. Recently, it has become possible to produce monodisperse, mesoporous TiO2 microparticles with engineered sizes using a hybrid sol-gel/hydrothermal technique. Further, it has also been shown that the size of monodisperse TiO2 microparticles affects the the photocatalytic activity.This study investigated whether using mondodisperse (M,N) TiO2 microparticles would further increase visible-light absorption for (M,N)TiO2. The first-row transition metals chosen for this study - Mn, Fe, Co, Ni, and Cu – have been characterized in the earlier (M,N) TiO2 UV-vis study, which was used as a baseline. The doping levels of the transition metals samples were set at the 2.5 percent level previously shown to be optimum for photocatalytic activity.

scholarly journals Improving the photocatalytic activity of nitrogen-doped surface defect TiO2-x nanobelts for degradation of organic pollutants

2020 ◽  
pp. 174751982093867
Author(s):  
Zhen Zhang ◽  
Shao-dong Qin ◽  
Jing-yun Chen ◽  
Jing Li ◽  
Ai-hua Xing
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Organic Pollutants ◽  
Rhodamine B ◽  
Light Absorption ◽  
Surface Defect ◽  
Separation Efficiency ◽  
Visible Light Absorption ◽  
Nitrogen Doped ◽  
N Doping

The synthesis of surface defect TiO2-x nanobelts with excellent visible light absorption is important to reduce costs, increase stability, and improve photocatalytic activity. In this work, we report that nitrogen-doped surface defect TiO2-x nanobelts are synthesized by annealing pristine TiO2 nanobelts in Ar/H2 (95%/5%) atmosphere followed by subsequent heat treatment in NH3 at various temperatures. The aim is to study the effect of the extent of the N-doping amount in the lattice of TiO2-x nanobelts on light absorption and photocatalytic activity. Considering the increase in organic pollutants in wastewater, the photocatalytic activity is measured by degrading rhodamine B (RhB) dye in water. The results demonstrate that the calcination temperature affects the doping level of N, and the b-TiO2-N550 sample exhibits higher photocatalytic performance than that of other samples under visible-light irradiation for the degradation of rhodamine B, which is up to 96.11%. The enhancement is ascribed to the synergistic effect of N-doping and self-doping oxygen vacancy (which extend the visible light absorption) and the separation efficiency of photogenerated carriers, which improves the photocatalytic activity.

scholarly journals Visible-light photocatalysis on C-doped ZnO derived from polymer-assisted pyrolysis

RSC Advances ◽  
2015 ◽  
Vol 5 (35) ◽  
pp. 27690-27698 ◽  
Author(s):  
Ahmad S. Alshammari ◽  
Lina Chi ◽  
Xiaoping Chen ◽  
Abdulaziz Bagabas ◽  
Denis Kramer ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Oxygen Vacancies ◽  
Charge Carriers ◽  
Visible Light Photocatalysis ◽  
Visible Light Absorption ◽  
C Doping ◽  
Doped Zno

Heavy C-doping can effectively enhance visible-light absorption yet exhibited lower visible-light-responsive photocatalytic activity due to significant recombination of photogenerated charge carriers caused by C-dopant and oxygen vacancies.

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