scholarly journals First-Principles Study of Optoelectronic Properties of the Noble Metal (Ag and Pd) Doped BiOX (X = F, Cl, Br, and I) Photocatalytic System

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 198 ◽  
Author(s):  
Shixiong Zhou ◽  
Tingting Shi ◽  
Zhihong Chen ◽  
Dmitri Kilin ◽  
Lingling Shui ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
First Principles ◽  
Density Functional ◽  
Optoelectronic Properties ◽  
Mulliken Charge ◽  
Light Spectrum ◽  
Full Spectrum ◽  
Electronegativity Difference ◽  
Type Semiconductor

To explore the photocatalytic performances and optoelectronic properties of pure and doped bismuth oxyhalides D-doped BiOX (D = Ag, Pd; X = F, Cl, Br, I) compounds, their atomic properties, electronic structures, and optical properties were systematically investigated using first-principles calculations. In previous experiments, the BiOX (X = Cl, Br) based system has been observed with enhanced visible light photocatalytic activity driven by the Ag dopant. Our calculations also show that the potential photocatalytic performance of Ag-doped BiOCl or BiOBr systems is enhanced greatly under visible light, compared with other Pd-doped BiOX (X = Cl, Br) compounds. Furthermore, it is intriguing to find that the Pd-doped BiOF compound has strong absorption over the infrared and visible light spectrum, which may offer an effective strategy for a promising full spectrum catalyst. Indicated by various Mulliken charge distributions and different impurity states in the gap when Ag or Pd was doped in the BiOX compounds, we notice that all D-doped BiOXs exhibit a p-type semiconductor, and all impurity levels originated from the D-4d state. The charge transfer, optoelectronic properties, and absorption coefficients for photocatalytic activities among D-doped BiOX photocatalysts caused by the electronegativity difference of halide elements and metal atoms will finally affect the photocatalytic activity of doped BiOX systems. Therefore, it is significant to understand the inside physical mechanism of the enhanced Ag/Pd-doped BiOX photocatalysts through density functional theory.

scholarly journals A Bi7.38Cr0.62O12+x crystal as a novel visible-light-active photocatalyst up to ∼650 nm

RSC Advances ◽  
2017 ◽  
Vol 7 (46) ◽  
pp. 28797-28801 ◽  
Author(s):  
W. X. Liao ◽  
X. L. Zhao ◽  
T. S. Wang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectric Response ◽  
Excellent Photocatalytic Activity ◽  
Visible Light Active ◽  
Type Semiconductor ◽  
New Type ◽  
P Type

A new type of Bi-based p-type semiconductor, Bi7.38Cr0.62O12+x, has a strong photoelectric response until 647.4 nm and an excellent photocatalytic activity for decomposition and O2 production.

A hybrid density functional study on the visible light photocatalytic activity of (Mo,Cr)–N codoped KNbO3

2015 ◽  
Vol 17 (43) ◽  
pp. 28743-28753 ◽  
Author(s):  
Guangzhao Wang ◽  
Hong Chen ◽  
Yang Li ◽  
Anlong Kuang ◽  
Hongkuan Yuan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Density Functional ◽  
Photocatalytic Performance ◽  
Functional Study ◽  
Redox Level ◽  
Hybrid Density Functional ◽  
Decomposition Of Water ◽  
Visible Light Photocatalytic

To improve the photocatalytic performance of KNbO3 for the decomposition of water into hydrogen and oxygen, the electronic structure of KNbO3 should be modified to have a suitable bandgap with band edge positions straddling the water redox level so as to sufficiently absorb visible light.

Enhanced visible light photocatalytic activity of anatase TiO2 through C, N, and F codoping

2014 ◽  
Vol 92 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Zongbao Li ◽  
Wang Xia ◽  
Lichao Jia
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Density Functional ◽  
Light Response ◽  
Anatase Tio2 ◽  
Functional Theory ◽  
Visible Light Response ◽  
Elemental Doping ◽  
Visible Light Photocatalytic ◽  
Good Agreement

The electronic and optical properties of pure, C-doped, (C, F)-codoped, (C, N)-codoped, and (C, N, F)-codoped anatase TiO2 are investigated by using density functional theory (DFT). The results indicate that elemental doping creates a much more efficient and stable photocatalyst than pristine, which narrows the band gap of TiO2 and realizes its visible light response activity. With the incorporation of F into (C, N)-codoped TiO2, strong visible light absorption and photocatalytic activity are further increased. It also verifies the reliability of our calculations for good agreement with the experimental results in the optical absorption of (C, N)-codoped and (C, N, F)-codoped.

scholarly journals Origin of Visible Light Photocatalytic Activity of Ag3AsO4from First-Principles Calculation

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yan Gong ◽  
Hongtao Yu ◽  
Xie Quan
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Density Functional ◽  
Photocatalytic Performance ◽  
Density Functional Method ◽  
Functional Method ◽  
First Principles Calculation ◽  
Visible Light Photocatalytic Activity ◽  
Valence Bands ◽  
Visible Light Photocatalytic

Recently a novel sliver oxide Ag3AsO4has been found to be an excellent photocatalyst with strong oxidation capability for pollutant degradation under visible light. But the origin of its high visible light photocatalytic activity was unclear which hindered further research of Ag3AsO4. For clarifying that, the electronic structure and optical properties of Ag3AsO4have been analyzed by the hybrid density functional method. The results reveal that the Ag3AsO4presents a narrow band gap with strong oxidation ability of the valence bands maximum edge and the highly delocalized charge distribution of the conduction bands minimum is beneficial for the carriers transfer to surface to participate in the photocatalytic reaction. These results provide clear explanations of the excellent visible light photocatalytic performance of the Ag3AsO4from microscopic aspect. And it is significant to design novel materials with high photocatalytic performance.

First-principles study on codoping effect to enhance photocatalytic activity of anatase TiO2

2017 ◽  
Vol 31 (06) ◽  
pp. 1750036
Author(s):  
Yujie Bai ◽  
Qinfang Zhang ◽  
Fubao Zheng ◽  
Yun Yang ◽  
Qiangqiang Meng ◽  
...  
Keyword(s):  
Visible Light ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Band Edge ◽  
Electron Hole ◽  
Functional Theory ◽  
Rich Condition

Codopant is an effective approach to modify the bandgap and band edge positions of transition metal oxide. Here, the electronic structures as well as the optical properties of pristine, mono-doped (N/P/Sb) and codoped (Sb, N/P) anatase TiO2 have been systematically investigated based on density functional theory calculations. It is found that mono-doped TiO2 exhibits either unoccupied or partially occupied intermediate state within the energy gap, which promotes the recombination of electron-hole pairs. However, the presence of (Sb, N/P) codopant not only effectively reduces the width of bandgap by introducing delocalized occupied intermediate states, but also adjusts the band edge alignment to enhance the hydrogen evolution activity of TiO2. Moreover, the optical absorption spectrum for (Sb, N/P) codoped TiO2, which is favored under oxygen-rich condition, demonstrates the improvement of its visible light absorption. These findings will promote the potential application of (Sb, N/P) codoped TiO2 photocatalysis for water splitting under visible light irradiation.

scholarly journals Visible Light Photocatalytic Properties of Modified Titanium Dioxide Nanoparticles via Aluminium Treatment

2016 ◽  
Vol 11 (1) ◽  
pp. 40 ◽  
Author(s):  
Dessy Ariyanti ◽  
Junzhe Dong ◽  
Junye Dong ◽  
Wei Gao
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Titanium Dioxide Nanoparticles ◽  
Wide Bandgap ◽  
Reaction Engineering ◽  
Photocatalytic Properties ◽  
Light Spectrum ◽  
Visible Light Range ◽  
Visible Light Photocatalytic

<p>Titanium dioxide (TiO2) has gained much attentions for the last few decades due to its remarkable performance in photocatalysis and some other related properties. However, its wide bandgap (~3.2 eV) can only absorb UV energy which is only ~5% of solar light spectrum. The objective of this research was to improve the photocatalytic activity of TiO2 by improving the optical absorption to the visible light range. Here, colored TiO2 nanoparticles range from light to dark grey were prepared via aluminium treatment at the temperatures ranging from 400 to 600 oC. The modified TiO2 is able to absorb up to 50% of visible light (400-700 nm) and shows a relatively good photocatalytic activity in organic dye (Rhodamine B) degradation under visible light irradiation compared with the commercial TiO2. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 10th November 2015; Revised: 7th January 2016; Accepted: 7th January 20 </em></p><p><strong>How to Cite</strong>: Ariyanti, D., Dong, J.Z., Dong, J.Y., Gao, W. (2016). Visible Light Photocatalytic Properties of Modified Titanium Dioxide Nanoparticles via Aluminium Treatment. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (1): 40-47. (doi:10.9767/bcrec.11.1.414.40-47)</p><p><strong>Permalink/DOI</strong>: <a href="http://dx.doi.org/10.9767/bcrec.11.1.414.40-47">http://dx.doi.org/10.9767/bcrec.11.1.414.40-47</a></p>

ELECTRONIC STRUCTURES OF S-DOPED ANATASE AND RUTILE TiO2

2007 ◽  
Vol 06 (01) ◽  
pp. 23-32 ◽  
Author(s):  
XIN-GUO MA ◽  
CHAO-QUN TANG ◽  
XIAO-HUA YANG
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Valence Band ◽  
Visible Light Irradiation ◽  
Electronic Structures ◽  
Density Functional ◽  
Visible Region ◽  
Light Irradiation ◽  
Band Shift ◽  
Deep Impurity

The electronic structures of S -doped TiO 2 have been carried out by first-principles calculations based on density functional theory with plane-wave ultrasoft pseudopotential method. Comparing anion doping with cation doping in anatase and rutile, we found different energy band structures and origins of photoactivity of S -doped TiO 2. For anion-doped TiO 2, new S –3p bands appear and which lie slightly above the top of the O –2p valence band. It plays a significant role in increasing absorbance in the visible region, resulting in improvement in photocatalytic activity under visible-light irradiation. For cation-doped TiO 2, the potential of the O –2p valence band shift much downwards, yielding the stronger oxidative power than that of undoped and S anion-doped TiO 2. Nevertheless, the deep impurity states in BG (bond gap) that originate from the S -dopant have negative effects on the recombination of the photoexcited electrons and holes. From our calculated results, we can explain their differences in photocatalytic activity under visible-light irradiation.

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