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.

In situ Synthesis of p–n LaFeO3/ZnIn2S4 Heterojunctions for Enhanced Photocatalytic Activity

NANO ◽  
2019 ◽  
Vol 14 (08) ◽  
pp. 1950096 ◽  
Author(s):  
Wen Gao ◽  
Chengjia Zhang ◽  
Sainan Cui ◽  
Qian Liang ◽  
Song Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
In Situ Synthesis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Composition Structure

In this study, LaFeO3/ZnIn2S4 composites were synthesized via in situ synthesis. The composition, structure and optical absorption properties of LaFeO3/ZnIn2S4 were characterized by X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy, fluorescence spectroscopy (PL), Fourier Transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The photocatalytic activity of the LaFeO3/ZnIn2S4 photocatalyst was determined based on the degradation of methyl orange (MO). LaFeO3/ZnIn2S4 composites showed much better photocatalytic performance compared with pure LaFeO3 and ZnIn2S4. The enhanced photocatalytic performance was attributed to intimately contacted interfaces and charge transfer channels which can effectively transfer and separate the photogenerated charge carriers.

scholarly journals Novel Ternary Heterogeneous Reduction Graphene Oxide (RGO)/BiOCl/TiO2 Nanocomposites for Enhanced Adsorption and Visible-Light Induced Photocatalytic Activity toward Organic Contaminants

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2529 ◽  
Author(s):  
Zhanxin Jing ◽  
Xiangyi Dai ◽  
Xueying Xian ◽  
Qiongshan Zhang ◽  
Huojiao Zhong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Organic Contaminants ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Hydrothermal Process ◽  
Reaction System ◽  
Cost Effective ◽  
Active Species ◽  
X Ray

Herein, we describe a simple and cost-effective design for the fabrication of a novel ternary RGO/BiOCl/TiO2 nanocomposites through a simple hydrothermal process. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and N2 adsorption–desorption analysis. Organic contaminants—such as methylene blue (MB), methyl orange (MO), rhodamine B (RhB) and amido black-10B (AB-10B)—were employed as the target pollutants to evaluate the adsorption capacity and photocatalytic activity of RGO/BiOCl/TiO2 nanocomposites. From experimental data, it was also found that the amount of TiO2 impressed the photocatalytic performance, and the nanocomposites with 10% of TiO2 showed the best photocatalytic activity. The improved photocatalytic performance may be mainly due to the narrow band gap, and the charge separation and migration of RGO. Moreover, good recyclability was obtained from RGO/BiOCl/TiO2 nanocomposites, and scavenger tests indicated that photogenerated holes were the main active species in the reaction system. Therefore, the prepared RGO/BiOCl/TiO2 nanocomposites have broad applications foreground in pollutants purification.

Sol-Gel Synthesis of Na2Ta4O11 Nanocrystals Showing High Efficient Photocatalytic Performance

2014 ◽  
Vol 1058 ◽  
pp. 35-39 ◽  
Author(s):  
Yi Guo Su ◽  
Xu Yang ◽  
Ting Ting Wang ◽  
Bao Ling Zhu ◽  
Xiao Jing Wang
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Active Species ◽  
Gap Energy ◽  
High Efficient ◽  
Sol Gel Synthesis

Semiconductors showing high efficient photocatalytic activity have attracted great interest, because they provide a potential solution to many environmental pollution problems that humankind is currently facing. This work reports on the sol-gel synthesis of Na2Ta4O11 nanocrystals and its photocatalytic performance toward Red G. The samples were carefully characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and the Barrett–Emmett–Teller technique. By modulating the synthetic condition, the sol-gel reaction yielded pure Na2Ta4O11 nanocrystals with diameter of ~32 nm from the peak broadening of (006) plane using Scherrer formula. It is found that the as-prepared Na2Ta4O11 nanocrystals showed a band gap energy of 3.63 eV, which is much smaller than that of Na2Ta4O11 prepared by flux approach. The relative narrowed band gap energy of Na2Ta4O11 nanocrystals may predict superior photocatalytic activity. By careful photocatalytic test, it is found that Na2Ta4O11 nanocrystals showed excellent photocatalytic activity toward Red G. The photocatalytic degradation efficiency was estimated to be 94.0% within a time intervals of 40 minutes. Controlled experiment by adding active species scavengers gave evidence that the degradation of Red G is dominated by the oxidation reaction of the generated O2-∙ active species taking place on the surface of the photocatalyst.

scholarly journals Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

2019 ◽  
Vol 6 (10) ◽  
pp. 191077 ◽  
Author(s):  
Zhencui Wang ◽  
Yuechao Song ◽  
Xingfei Cai ◽  
Jun Zhang ◽  
Tianle Tang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Titanium Dioxide Nanoparticles ◽  
Earth Metal ◽  
Nitrate Hexahydrate ◽  
Doping Amount ◽  
X Ray ◽  
Low Toxicity

Further applications of photocatalysis were limited by the high recombination probability of photo-induced electron–hole pairs in traditional titanium dioxide nanoparticles (TiO 2 NPs). Herein, we modified them with rare earth metal via a facile sol–gel method, using tetrabutyl titanate as a precursor and terbium (III) nitrate hexahydrate as terbium (Tb) source. The resulting samples with different Tb doping amounts (from 0 to 2%) have been characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photo-electron spectroscopy and a scanning electron microscope. The photocatalytic performance of Tb-doped TiO 2 was evaluated by the degradation of methylene blue. The effects of Tb doping amount and initial pH value of solution were investigated in detail. The composite with Tb doping amount of 1.0 wt% showed the highest photocatalytic performance. It exhibited approximately three times enhancement in photocatalytic activity with a reaction rate constant of 0.2314 h −1 when compared with that of commercial P25 (0.0827 h −1 ). In addition, it presented low toxicity on zebrafishes with 96 h-LC 50 of 23.2 mg l −1 , and has been proved to be reusable for at least four cycles without significant loss of photocatalytic activity. A probable photocatalytic mechanism of Tb-doped TiO 2 was proposed according to the active species trapping experiments. The high photocatalytic performance, excellent reusability and low toxicity of Tb-doped TiO 2 indicated that it is a promising candidate material in the future treatment of dye wastewater.

scholarly journals Synthesis of TiO2/Pd and TiO2/PdO Hollow Spheres and Their Visible Light Photocatalytic Activity

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Jing Yan ◽  
Xiaojuan Li ◽  
Bo Jin ◽  
Min Zeng ◽  
Rufang Peng
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Hollow Spheres ◽  
Active Species ◽  
Degradation Efficiency ◽  
Diffraction Field ◽  
Transmission Electron

A series of TiO2, TiO2/Pd, and TiO2/PdO hollow sphere photocatalysts was successfully prepared via a combination of hydrothermal, sol-immobilization, and calcination methods. The structure and optical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Telleranalysis, Barrett-Joyner-Halenda measurement, and UV-Vis diffuse reflectance spectroscopy. The photocatalysis efficiencies of all samples were evaluated through the photocatalytic degradation of rhodamine B under visible light irradiation. Results indicated that TiO2/PdO demonstrated a higher photocatalytic activity (the photocatalytic degradation efficiency could reach up to 100% within 40 min) than the other samples and could maintain a stable photocatalytic degradation efficiency for at least four cycles. Finally, after using different scavengers, superoxide and hydroxyl radicals were identified as the primary active species for the effectiveness of the TiO2/PdO photocatalyst.

scholarly journals In situ structural modification of graphitic carbon nitride by alkali halides and influence on photocatalytic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (52) ◽  
pp. 32592-32600 ◽  
Author(s):  
Yan Xu ◽  
Yinyan Gong ◽  
Hui Ren ◽  
Wenbo Liu ◽  
Lengyuan Niu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Basal Plane ◽  
Carbon Nitride ◽  
Structural Modification ◽  
Photocatalytic Performance ◽  
Alkali Halides ◽  
Thermal Condensation ◽  
Carrier Transfer

Introducing alkali halides during thermal condensation of melamine disturbs periodic ordering in the basal plane, reduces the band gap, and facilitates charge carrier transfer and separation, and thus enhances the photocatalytic performance of g-C3N4.

One-step in situ synthesis of BiOCl/(BiO)2CO3 composite photocatalysts with exposed high-energy {001} facets

CrystEngComm ◽  
2018 ◽  
Vol 20 (48) ◽  
pp. 7838-7850 ◽  
Author(s):  
Yingying Chen ◽  
Yan Zhou ◽  
Qimei Dong ◽  
Hanming Ding
Keyword(s):  
Photocatalytic Activity ◽  
Synergistic Effect ◽  
Solvothermal Method ◽  
High Energy ◽  
In Situ Synthesis ◽  
Band Alignment ◽  
Type Ii ◽  
Composite Photocatalysts ◽  
One Step

BiOCl/(BiO)2CO3 composites with reactive exposed {001} facets have been synthesized by a one-step in situ solvothermal method. The synergistic effect of type-II band alignment and exposed high-energy facets enhances photocatalytic activity.

scholarly journals Enhanced Photocatalytic Activity of Electrospun β-Ga2O3 Nanofibers via In-Situ Si Doping Using Tetraethyl Orthosilicate

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1005 ◽  
Author(s):  
Tae Hee Yoo ◽  
Heejoong Ryou ◽  
In Gyu Lee ◽  
Byung Jin Cho ◽  
Wan Sik Hwang
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Oxidation Potential ◽  
Si Doping ◽  
Defect Sites ◽  
Electrospinning Method ◽  
Ultraviolet C ◽  
Si Doped ◽  
High Reduction

β-Ga2O3 has attracted considerable attention as an alternative photocatalyst to replace conventional TiO2 under ultraviolet-C irradiation due to its high reduction and oxidation potential. In this study, to enhance the photocatalytic activity of β-Ga2O3, nanofibers are formed via the electrospinning method, and Si atoms are subsequently doped. As the Si concentration in the β-Ga2O3 nanofiber increases, the optical bandgap of the β-Ga2O3 nanofibers continuously decreases from 4.5 eV (intrinsic) to 4.0 eV for the Si-doped (2.4 at. %) β-Ga2O3 nanofibers, and accordingly, the photocatalytic activity of the β-Ga2O3 nanofibers is enhanced. This higher photocatalytic performance with Si doping is attributed to the increased doping-induced carriers in the conduction band edges. This differs from the traditional mechanism in which the doping-induced defect sites in the bandgap enhance separation and inhibit the recombination of photon-generated carriers.

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