scholarly journals N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1657 ◽  
Author(s):  
Hao Peng ◽  
Daixin Liu ◽  
Xiaogang Zheng ◽  
Xiaojin Fu

In this work, N-doped carbon-coated ZnS with a sulfur-vacancy defect (ZnS@N-C) was performed for the visible-light-driven photodegradation of tetracycline hydrochloride (TCH). The obtained ZnS@N-C exhibited enhanced photocatalytic activity compared with ZnS for TCH removal. Among these ZnS@N-C composites, ZnS@N-C-3 with N-doped content of 3.01% (100 nm) presented the best visible-light photocatalytic activity and superior long-term photocatalytic stability after five cycle times for TCH removal in the visible light region. This may be ascribed to the interface between the N-doped carbon shell and ZnS with a sulfur-vacancy defect for efficient charge transfer and the restrained recombination of charge carriers. Electron spin resonance (ESR) results indicate that the ·O2‒ radical plays a crucial role in the enhanced photocatalytic activity of ZnS@N-C-3.

2010 ◽  
Vol 62 (9) ◽  
pp. 2128-2133 ◽  
Author(s):  
T. Putta ◽  
M. C. Lu ◽  
J. Anotai

This research aimed to expand the activity of TiO2 down to the visible light region by modifying the sol-gel conditions and doping with tungsten. The optimum conditions for calcination temperature, acid type, and heating rate were 200°C, HNO3, and 1°C/min, respectively. The undoped TiO2 synthesized under these conditions could significantly absorb the visible light whereas the commercial Degussa P-25 could not. The absorptivity decreased sequentially as the wavelength increased from 400 to 700 nm. Within 6 h of 2-W blue-light illumination, 23% of 0.1 mM 2-chlorophenol was removed. The XRD result showed that the crystalline was anatase phase. The visible-light absorption property of the TiO2 became even better when doped with tungsten. At the optimum W to TiO2 ratio of 0.5%, the degradation of 0.1 mM 2-chlorophenol increased to 53% indicating a higher photocatalytic activity. Both crystalline and amorphous TiO2 could exhibit the photocatalytic activity under the visible light region.


2018 ◽  
Vol 25 (Supp01) ◽  
pp. 1840002 ◽  
Author(s):  
NIDCHAMON JUMRUS ◽  
ARISARA PANTHAWAN ◽  
TEWASIN KUMPIKA ◽  
WATTIKON SROILA ◽  
EKKAPONG KANTARAK ◽  
...  

In this work, calcium (Ca)-modified titanium dioxide (TiO2) nanoparticulate (NP) films were successfully prepared using sparking off Ca-electroplated Ti tips. Aqueous solution of calcium carbonate (CaCO3) was used as electrolyte in the electroplating process. The experiment was carried out using electric current of 0.02[Formula: see text]mA applied to titanium electrodes for 10[Formula: see text]min. The NP films with small and uniform size were deposited on quartz substrate using the sparking process with a high DC voltage of 4[Formula: see text]kV in ambient air. The as-deposited NP films were then annealed at 800∘C, 900∘C and 1000∘C for 3[Formula: see text]h under atmospheric pressure to improve their crystallinity. Morphology, structural and optical properties of the NP films were characterized by SEM, XRD, Raman, XPS and UV-Vis spectroscopy. The effects of annealing temperature on the properties of the as-deposited and annealed NP films were reported. Furthermore, photocatalytic activity against 10 [Formula: see text]M of methylene blue (MB) under visible light region will be discussed.


Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1567 ◽  
Author(s):  
Xiaogang Zheng ◽  
Yiting Mao ◽  
Jing Wen ◽  
Xiaojin Fu ◽  
Xinhui Liu

CuInS2/Mg(OH)2 (CIS/Mg(OH)2) nanosheets have been prepared for the visible light activated photodegradation of tetracycline hydrochloride (TCH). The introduction of CuInS2 has proven to enhance the photocatalytic activity of Mg(OH)2 nanosheets. It’s ascribed to the enhanced transfer and separation of charge carriers at the junction interface between CuInS2 and Mg(OH)2. The photocatalytic activity of obtained CIS/Mg(OH)2 is greatly affected by CuInS2 content, pH value, and inorganic ions. Among these samples, 2-CIS/Mg(OH)2 exhibits the excellent photocatalytic activity and durability for the visible light driven removal of TCH after five cycle times. Atomic force microscope (AFM) images indicate that the surface roughness of 2-CIS/Mg(OH)2 is intensively influenced in adsorption-photocatalysis process. The •O2− and •OH radicals are vital for the visible light driven photocatalytic activity of 2-CIS/Mg(OH)2 for TCH removal.


2006 ◽  
Vol 78 (12) ◽  
pp. 2267-2276 ◽  
Author(s):  
Kazuhiko Maeda ◽  
Kentaro Teramura ◽  
Nobuo Saito ◽  
Yasunobu Inoue ◽  
Hisayoshi Kobayashi ◽  
...  

Oxynitride photocatalysts with d10 electronic configuration are presented as effective non-oxide catalysts for overall water splitting. Germanium nitride (β-Ge3N4) having a band gap of 3.8-3.9 eV modified with RuO2 nanoparticles as a cocatalyst is shown to achieve stoichiometric decomposition of H2O into H2 and O2 under UV irradiation (λ > 200 nm). A novel solid solution of GaN and ZnO, (Ga1-xZnx)(N1-xOx), with a band gap of 2.4-2.8 eV (depending on composition) achieves overall water splitting under visible light (λ > 400 nm) when loaded with an appropriate cocatalyst. The narrower band gap of the solid solution is attributed to the bonding between Zn and N atoms at the top of the valence band. The photocatalytic activity of (Ga1-xZnx)(N1-xOx) for overall water splitting is strongly dependent on both the cocatalyst and the crystallinity and composition of the material. The quantum efficiency of (Ga1-xZnx)(N1-xOx) with Rh and Cr mixed-oxide nanoparticles is 2-3 % at 420-440 nm, which is the highest reported efficiency for overall water splitting in the visible-light region.


2012 ◽  
Vol 548 ◽  
pp. 105-109
Author(s):  
Nguyen Minh Thuy ◽  
Duong Quoc Van ◽  
Le Thi Hong Hai ◽  
Nguyen Manh Nghia ◽  
Nguyen Hong Quan

TiO2and Vanadium doped TiO2nanoparticles were synthesized by hydrothermal method. The solvents are water, oleic acid, or oxalic acid, which have affected the forms and sizes of the grains in the samples. The solvent can make the spherical nanograins, or the stick form grains, what influences the photo activity of the materials. The Vanadium doped TiO2nanoparticles had identical anatase phase with average crystal size of 8-20nm. The absorption spectra of doped samples exhibited the long tailed absorption in the visible light region above 380nm. The photocatalytic activity under the irradiation of visible light was evaluated by the degradation of phenol aqueous solutions, which is one of the products from photocatalytic oxidations of benzene. The samples TiO2:0.5%V4+have visible light photocatalystic activity; after 360min under the visible irradiation the normalized concentration of phenol decreased to 9%.


RSC Advances ◽  
2019 ◽  
Vol 9 (24) ◽  
pp. 13787-13796 ◽  
Author(s):  
Jinyang Zhang ◽  
Fuyan Kang ◽  
Hao Peng ◽  
Jing Wen ◽  
Xiaogang Zheng

Ag-loaded Cu0.25Zn0.75S (Ag/Cu0.25Zn0.75S) photocatalysts were synthesized for the photodegradation of organic pollutants such as rhodamine B (RhB), methyl violet (MV) and ciprofloxacin hydrochloride (CIP) under visible-light irradiation.


2020 ◽  
Vol 12 (3) ◽  
pp. 449-453 ◽  
Author(s):  
Bo Wang ◽  
Ruiling Zhang ◽  
Jin Xu ◽  
Songyan Qin ◽  
Jiajun Zheng ◽  
...  

N doped TiO2 nano-crystalline was prepared through hydrolysis-precipitation process in the presence of ammonia water. The resulting materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). It was found that N was incorporated into the lattice of TiO2 through substituting lattice oxygen atoms and coexisted in the forms of substitutional N (O–Ti–N) and interstitial N (Ti–O–N). Further, doping with N could greatly improve the phase transformation of TiO2 from rutile to anatase and light absorption in visible light region. The high visible light photocatalytic activity for the degradation of RhB of N doped TiO2 was mainly attributed to the small crystallite size, mixed phase composition, intense light absorption in visible light region, narrow band gap energy and surface hydroxyl groups.


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