Novel dual-petal nanostructured WS2@MoS2 with enhanced photocatalytic performance and a comprehensive first-principles investigation

2015 ◽  
Vol 3 (40) ◽  
pp. 20225-20235 ◽  
Author(s):  
Honglin Li ◽  
Ke Yu ◽  
Chao Li ◽  
Bangjun Guo ◽  
Xiang Lei ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Composite Structure ◽  
First Principles ◽  
Energy Band ◽  
Photocatalytic Performance ◽  
First Principles Calculation ◽  
Type Ii

A prominent enhanced photocatalytic activity of the WS2@MoS2 heterojunction was obtained. The first-principles calculation showed that a well-defined type-II staggered energy band was formed for the composite structure.

scholarly journals In Situ Construction of a MgSn(OH)6 Perovskite/SnO2 Type-II Heterojunction: A Highly Efficient Photocatalyst towards Photodegradation of Tetracycline

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 53 ◽  
Author(s):  
Yuanyuan Li ◽  
Xiaofang Tian ◽  
Yaoqiong Wang ◽  
Qimei Yang ◽  
Yue Diao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Ultraviolet Irradiation ◽  
Photocatalytic Oxidation ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Species ◽  
Growth Strategy ◽  
Type Ii ◽  
Highly Efficient

Using solar energy to remove antibiotics from aqueous environments via photocatalysis is highly desirable. In this work, a novel type-II heterojunction photocatalyst, MgSn(OH)6/SnO2, was successfully prepared via a facile one-pot in situ hydrothermal method at 220 °C for 24 h. The obtained heterojunctions were characterized via powder X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic performance was evaluated for photodegradation of tetracycline solution under ultraviolet irradiation. The initial concentration of tetracycline solution was set to be 20 mg/L. The prepared heterojunctions exhibited superior photocatalytic activity compared with the parent MgSn(OH)6 and SnO2 compounds. Among them, the obtained MgSn(OH)6/SnO2 heterojunction with MgCl2·6H2O:SnCl4·5H2O = 4:5.2 (mmol) displayed the highest photocatalytic performance and the photodegradation efficiency conversion of 91% could be reached after 60 min under ultraviolet irradiation. The prepared heterojunction maintained its performance after four successive cycles of use. Active species trapping experiments demonstrated that holes were the dominant active species. Hydroxyl radicals and superoxide ions had minor effects on the photocatalytic oxidation of tetracycline. Photoelectrochemical measurements were used to investigate the photocatalytic mechanism. The enhancement of photocatalytic activity could be assigned to the formation of a type-II junction photocatalytic system, which was beneficial for efficient transfer and separation of photogenerated electrons and holes. This research provides an in situ growth strategy for the design of highly efficient photocatalysts for environmental restoration.

Investigation of Electronic Structures of F-Doped TiO2 by First-Principles Calculation

2009 ◽  
Vol 620-622 ◽  
pp. 647-650 ◽  
Author(s):  
Ying Cui ◽  
Hao Du ◽  
Li Shi Wen
Keyword(s):  
Photocatalytic Activity ◽  
First Principles ◽  
Electronic Structures ◽  
Lower Energy ◽  
Anatase Tio2 ◽  
First Principles Calculation ◽  
Visible Light Region ◽  
Doped Tio2 ◽  
Light Region ◽  
Calculation Results

F-doped TiO2 has exhibited superior photocatalytic activity. However, its electronic structures and photocatalysis mechanism are still unclear. In the present work, the structural optimization and electronic structure of F-doped anatase TiO2 have been investigated by means of the first-principles pseudopotential total energy method. It has been demonstrated that F doping would modify the valence band at the lower energy direction in the F-doped TiO2. Calculation results confirm that doping of fluorine would not shift the absorption edge into the visible light region. Instead, we attributed its photocatalytic activity to the enhancement of the oxidative power of F-doped TiO2.

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.

scholarly journals Investigation on Structural and Electrochemical Properties of Olivine-Structured LiMn1-xFexPO4/C Cathode Materials Based on First-Principles Calculation

2021 ◽  
Author(s):  
Longjiao Chang ◽  
Xiaolong Bi ◽  
Shaohua Luo ◽  
Shiyuan Cao ◽  
Anlu Wei ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
First Principles ◽  
Energy Band ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
First Principles Calculation ◽  
Cycle Performance ◽  
Total Density ◽  
Electrochemical Tests ◽  
Experimental Findings

Abstract Currently, LiMnPO4 is a highly prevalent cathode material in lithium-ion batteries. However, its low conductivity and Li+ diffusion rate limit its practical application. To overcome these inherent defect, we have modified its properties by doping Fe at the Mn site. In the LiMn1-xFexPO4 system, the total density of states of electrons near the Fermi level and the energy band of the Fermi surface are obtained by first-principles calculation. The adjustment of the energy band width immediately influences the electronic conductivity of LiMn1-xFexPO4 system, which is positively related to the electrochemical performance. According to the results of first-principles calculation, we speculated that x=1/4 was the optimal doping concentration. Then, the LiMn1-xFexPO4/C systems were compounded by hydrothermal method to verify the first-principles’ hypothesis. The electrochemical tests show that the LiMn3/4Fe1/4PO4/C material has the best cycle performance and rate performance. At the condition of 0.05 C rate, this material possesses an initial discharge capacity of 142.5 mAh/g. with the capacity retention maintained 93.9% after 100 cycles. The theoretical calculation in consistent with the experimental findings, which accounts for the fact that the first-principles strategy is very effective in the research and development of lithium-ion batteries.

scholarly journals Construction of 2D/2D layered g-C3N4/Bi12O17Cl2 hybrid material with matched energy band structure and its improved photocatalytic performance

RSC Advances ◽  
2018 ◽  
Vol 8 (43) ◽  
pp. 24500-24508 ◽  
Author(s):  
Lei Shi ◽  
Weiwei Si ◽  
Fangxiao Wang ◽  
Wei Qi
Keyword(s):  
Photocatalytic Activity ◽  
Band Structure ◽  
Hybrid Material ◽  
Energy Band ◽  
Photocatalytic Performance ◽  
Energy Band Structure ◽  
Surface Contact

Surface-to-surface contact g-C3N4/Bi12O17Cl2 hybrid material with a matched energy band structure could efficiently transfer photoinduced charges, improving the photocatalytic activity.

Functionalization of two-dimensional 1T′-ReS2 with surface ligands for use as a photocatalyst in the hydrogen evolution reaction: a first-principles calculation study

2020 ◽  
Vol 22 (17) ◽  
pp. 9415-9423
Author(s):  
Jing Pan ◽  
Wannian Zhang ◽  
Xiaoyong Xu ◽  
Jingguo Hu
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Surface Functionalization ◽  
First Principles ◽  
First Principles Calculation ◽  
Two Dimensional ◽  
Surface Ligands

Surface functionalization with polar ligands to tune band edges of two-dimensional 1T′-ReS2 and enhance its photocatalytic activity for hydrogen production.

Characterization of Ag-TiO2 Electronic Structures and Nanotubes Based on First-Principles Calculation

2014 ◽  
Vol 609-610 ◽  
pp. 20-25
Author(s):  
Jing Ling Li ◽  
Xiao Xia Cao ◽  
Bo Wu ◽  
Hua Liang Yu ◽  
Yong Jiang Gan
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Energy Band ◽  
Electronic Structures ◽  
Density Functional ◽  
Surface Acidity ◽  
First Principles Calculation ◽  
Oh Radicals ◽  
Ambient Atmosphere ◽  
Ag Doping

In this manuscript, we report the simulation of electronic structures of TiO2 doped with Ag using first-principles calculation, based on the density functional theory (DFT) The mechanism to improve the visible-light photocatalytic activity for TiO2 doped with Ag. EF was displaced into the valence band (VB), narrowing the band gap. An independent energy band was also introduced above the VB and an energy band with the width of 0.9 eV is introduced under the conduction band (CB), also resulting in the narrowing of the band gap. New VB and CB were formed by three orbitals O-2p, Ti-3d and Ag-4d. Composite TiO2 nanotubes with Ag-doping were synthesized using the alkaline fusion and hydrothermal method under ambient atmosphere. XRD results indicated composite Ag-TiO2 nanotubes ranging from the single anatase phase to the anatase and rutile mixed phase. XPS showed an increase in the surface acidity and photo catalytic activity of TiO2 nanotubes due to the presence of OH radicals. Furthermore Ag-doping also facilitated the separation of photo-holes and photo-electrons and enhanced the optical properties.

scholarly journals First Principles Calculation for Photocatalytic Activity of GaAs Monolayer

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yilimiranmu Rouzhahong ◽  
Mariyemu Wushuer ◽  
Mamatrishat Mamat ◽  
Qing Wang ◽  
Qian Wang
Keyword(s):  
Photocatalytic Activity ◽  
First Principles ◽  
First Principles Calculation
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