scholarly journals A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1039
Author(s):  
Dafu Jiang ◽  
Tunmise Ayode Otitoju ◽  
Yuanyuan Ouyang ◽  
Noor Fazliani Shoparwe ◽  
Song Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Active Sites ◽  
Crystal Surface ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Tio2 Photocatalyst ◽  
Electron Hole ◽  
Visible Light Range ◽  
Low Toxicity ◽  
High Chemical Stability

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

scholarly journals Photocatalytic Adsorption Synergistic Degradation of Tetracycline by Z-scheme Bi2WO6/ZIF-8

2021 ◽  
Author(s):  
Xiaojun Dai ◽  
sheng feng ◽  
Wei Wu ◽  
Yun Zhou ◽  
Zhiwei Ye ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Utilization Efficiency ◽  
Electron Hole ◽  
Effects Of Ph ◽  
Growth Method ◽  
Synergistic Degradation ◽  
First Time

Abstract In this paper, in order to improved the photocatalytic activity of Bi2WO6, Bi2WO6 and ZIF-8 were successfully combined by in-situ growth method for the first time. The addition of ZIF-8 effectively inhibited the recombination of photogenerated electron hole pairs and further improved the electron utilization efficiency, and superoxide anion was introduced to greatly improve the photocatalytic activity. The performance of Bi2WO6/ZIF-8 in the photodegradation of tetracycline (TC) was studied under different conditions of proportions of ZIF-8, dosage of catalyst and concentration of TC. The results indicated that B/Z/5/1 (10mg) had the best photocatalytic activity, and 97.8% of TC (20mg/L) could be degraded in 80 minutes under UV light, the rate constant (k) for TC degradation was almost 3 times that of Bi2WO6. The effects of pH, HA and inorganic anions on the degradation of TC were studied in simulated real water. Further, B/Z/5/1 could be reutilized up to five cycles without reduction of efficiency and catalysis performance. Therefore, Bi2WO6/ZIF-8 heterojunction composite material can be utilized as an efficient photocatalyst for remediation of environmental pollution.

Photocatalytic Enhancement in Methylene Blue Degradation of TiO2 Photocatalysts via Graphene Hybridization

2012 ◽  
Vol 512-515 ◽  
pp. 1677-1681
Author(s):  
Feng Zhou ◽  
Ying Qing Fu ◽  
Xin Wan
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Uv Light ◽  
Light Irradiation ◽  
Tio2 Photocatalyst ◽  
Electron Hole ◽  
Methylene Blue Degradation ◽  
Uv Light Irradiation ◽  
High Migration ◽  
Facile Route

A facile route was demonstrated to obtain an efficient graphene-hybridized TiO2 photocatalyst. The photodegradation results of Methylene Blue over graphene hybridized with TiO2 showed that the photocatalytic activity could be significantly enhanced under UV light irradiation. The structure between TiO2 and graphene as well as its effect on the photocatalytic activity were systematically investigated. The mechanism of the enhanced photocatalytic activity is based to the high migration efficiency and the inhibition of recombination of photoinduced electron-hole pairs. The graphene hydridization is proven to be a promising approach to develop highly efficient and stable photocatalysts under UV light irradiation.

scholarly journals VISIBLE-LIGHT DEGRADATION OF INDIGO CARMINE USING A NOVEL MIXED METAL OXIDES/REDUCED GRAPHENE OXIDE HYBRID CATALYSTS

2019 ◽  
Vol 57 (5) ◽  
pp. 572
Author(s):  
Dang Nguyen Nha Khanh ◽  
Nguyen Thi Mai Tho ◽  
Nguyen Quoc Thang ◽  
Nguyen Thanh Tien ◽  
Chau Tan Phong ◽  
...  
Keyword(s):  
Visible Light ◽  
Indigo Carmine ◽  
Photogenerated Electron ◽  
Precipitation Method ◽  
Mixed Metal Oxides ◽  
Electron Hole ◽  
Hybrid Catalysts ◽  
Reduced Graphene ◽  
Visible Light Degradation ◽  
High Chemical Stability

A novel ZnBi2O4/rGO hybrid catalysts had been synthesized by a simple precipitation method. The crystallinity, structural, and morphological features were studied by XRD, FE-SEM and UV-Vis diffused reflectance  techniques. The photocatalytic activity of ZnBi2O4/rGO catalysts were evaluated by degradation of Indigo Carmine dye under visible-light irradiation. The enhancement of photocatalytic properties of ZnBi2O4/rGO attributed to the synergistic effect between ZnBi2O4 and rGO, which effectively separation of the photogenerated electron-hole pairs in ZnBi2O4. Moreover, the obtained ZnBi2O4/rGO displayed high chemical stability after four consecutive experiments under visible light.

Enhanced visible light photocatalytic activity of AgI/TiO2 composite fabricated by a grinding method

2019 ◽  
Vol 54 (3) ◽  
pp. 257-264
Author(s):  
Jin Xu ◽  
Dasheng Gao ◽  
Shuang Cui ◽  
Xiaohua Wang ◽  
Ningning Liu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Photogenerated Electron ◽  
Active Species ◽  
Electron Hole ◽  
Grinding Method ◽  
The Stability ◽  
Visible Light Photocatalytic

Abstract Through a simple grinding method, AgI/TiO2 composites were successfully synthesized. The as-prepared AgI/TiO2 composites were used as photocatalysts for Rhodamine B (RhB) degradation under visible light irradiation and exhibited excellent photocatalytic performance. In the presence of composites, almost 100% RhB was decomposed after 60 min. The photocatalytic activity of AgI/TiO2-0.5 composite was optimal, which was 9.5 times higher than that of pristine TiO2, and 15.6 times higher than that of AgI. Moreover, experimental results revealed that the improved photocatalytic activity was not only ascribed to the loading AgI but also resulted from the method that enabled the exposure of more active sites in the composites. In addition, the intimate interfacial contact obtained by this method could also promote the efficient separation of photogenerated electron-hole pairs. Moreover, the possible photocatalytic active species and the stability of the photocatalyst were investigated in detail.

scholarly journals Improving Photocatalytic Degradation Activity of Organic Pollutant by Sn4+ Doping of Anatase TiO2 Hierarchical Nanospheres with Dominant {001} Facets

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1603 ◽  
Author(s):  
Meiling Sun ◽  
Weichong Kong ◽  
Yunlong Zhao ◽  
Xiaolin Liu ◽  
Jingyue Xuan ◽  
...  
Keyword(s):  
Light Absorption ◽  
Active Sites ◽  
Organic Pollutant ◽  
Photogenerated Electron ◽  
High Energy ◽  
Charge Carriers ◽  
Photon Absorption ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
Electron Hole

Herein, high-energy {001} facets and Sn4+ doping have been demonstrated to be effective strategies to improve the surface characteristics, photon absorption, and charge transport of TiO2 hierarchical nanospheres, thereby improving their photocatalytic performance. The TiO2 hierarchical nanospheres under different reaction times were prepared by solvothermal method. The TiO2 hierarchical nanospheres (24 h) expose the largest area of {001} facets, which is conducive to increase the density of surface active sites to degrade the adsorbed methylene blue (MB), enhance light scattering ability to absorb more incident photons, and finally, improve photocatalytic activity. Furthermore, the SnxTi1−xO2 (STO) hierarchical nanospheres are fabricated by Sn4+ doping, in which the Sn4+ doping energy level and surface hydroxyl group are beneficial to broaden the light absorption range, promote the generation of charge carriers, and retard the recombination of electron–hole pairs, thereby increasing the probability of charge carriers participating in photocatalytic reactions. Compared with TiO2 hierarchical nanospheres (24 h), the STO hierarchical nanospheres with 5% nSn/nTi molar ratio exhibit a 1.84-fold improvement in photodegradation of MB arising from the enhanced light absorption ability, increased number of photogenerated electron–hole pairs, and prolonged charge carrier lifetime. In addition, the detailed mechanisms are also discussed in the present paper.

UV Light Activated Multi-Cycle Photoelectric Properties of TiO2 and CdS/TiO 2 Films in Formaldehyde

2021 ◽  
Vol 21 (11) ◽  
pp. 5642-5647
Author(s):  
Zhijun Zou ◽  
Zhongli Qu ◽  
Longtao Tang ◽  
Yang Qiu ◽  
Gaohua Liao ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Cycle Time ◽  
Screen Printing ◽  
Uv Light ◽  
Photogenerated Electron ◽  
The Other ◽  
Electron Hole ◽  
Silar Method ◽  
Cycle Number ◽  
Photoelectric Properties

In this work, UV light activated multi-cycle photoelectric properties of TiO2 and CdS/TiO2 films in formaldehyde were researched. TiO2 film was prepared by screen printing, CdS/TiO2 compounded film was synthesized by SILAR method. XRD and FE-SEM was used to characterize the TiO2 and CdS/TiO2 samples. Multi-cycle photoelectric properties of TiO2 and CdS/TiO2 with uv light on and off were evaluated by testing the photocurrent. On one hand, under the same bias voltage, CdS/TiO 2showed a higher photocurrent than that by TiO2. The reason for this result should be ascribed to the compounded structure in CdS/TiO2, with which the separation and transfer of photogenerated electron-hole pairs could be improved. On the other hand, with the testing cycle number increased, the photocurrent amplitudes of TiO2 and CdS/TiO2 increased. These results suggested that the time to reach a stable photocurrent value for TiO2 and CdS/TiO2 is much longer than one cycle time (300 S). To illustrate the increased photocurrent amplitude value cycle by cycle, the photocurrent of CdS/TiO2 to a much longer time (more than 4000 seconds) was also tested. To explain these results, corresponding possible illustrations were presented.

scholarly journals Construction of Ag3PO4/SnO2 Heterojunction on Carbon Cloth with Enhanced Visible Light Photocatalytic Degradation

2020 ◽  
Vol 10 (9) ◽  
pp. 3238
Author(s):  
Min Liu ◽  
Guangxin Wang ◽  
Panpan Xu ◽  
Yanfeng Zhu ◽  
Wuhui Li
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Carbon Cloth ◽  
Electron Hole ◽  
Step Process ◽  
Photogenerated Electrons ◽  
Rapid Transfer ◽  
Visible Light Photocatalytic

In this study, the Ag3PO4/SnO2 heterojunction on carbon cloth (Ag3PO4/SnO2/CC) was successfully fabricated via a facile two-step process. The results showed that the Ag3PO4/SnO2/CC heterojunction exhibited a remarkable photocatalytic performance for the degradation of Rhodamine B (RhB) and methylene blue (MB), under visible light irradiation. The calculated k values for the degradation of RhB and MB over Ag3PO4/SnO2/CC are 0.04716 min−1 and 0.04916 min−1, which are higher than those calculated for the reactions over Ag3PO4/SnO2, Ag3PO4/CC and SnO2/CC, respectively. The enhanced photocatalytic activity could mainly be attributed to the improved separation efficiency of photogenerated electron-hole pairs, after the formation of the Ag3PO4/SnO2/CC heterojunction. Moreover, carbon cloth with a large specific surface area and excellent conductivity was used as the substrate, which helped to increase the contact area of dye solution with photocatalysts and the rapid transfer of photogenerated electrons. Notably, when compared with the powder catalyst, the catalysts supported on carbon cloth are easier to quickly recycle from the pollutant solution, thereby reducing the probability of recontamination.

scholarly journals Preparation and Photocatalytic Performance for Degradation of Rhodamine B of AgPt/Bi4Ti3O12 Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2206
Author(s):  
Gaoqian Yuan ◽  
Gen Zhang ◽  
Kezhuo Li ◽  
Faliang Li ◽  
Yunbo Cao ◽  
...  
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Rhodamine B ◽  
Photocatalytic Performance ◽  
Bimetallic Nanoparticles ◽  
Resonance Effect ◽  
Visible Region ◽  
Photogenerated Electron ◽  
Pt Nanoparticles ◽  
Electron Hole

Loading a noble metal on Bi4Ti3O12 could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons and photoholes. In this paper, AgPt/Bi4Ti3O12 composite photocatalysts were prepared using the photoreduction method, and the effects of the type and content of noble metal on the photocatalytic performance of the catalysts were investigated. The photocatalytic degradation of rhodamine B (RhB) showed that the loading of AgPt bimetallic nanoparticles significantly improved the catalytic performance of Bi4Ti3O12. When 0.10 wt% noble metal was loaded, the degradation rate for RhB of Ag0.7Pt0.3/Bi4Ti3O12 was 0.027 min−1, which was respectively about 2, 1.7 and 3.7 times as that of Ag/Bi4Ti3O12, Pt/Bi3Ti4O12 and Bi4Ti3O12. The reasons may be attributed as follows: (i) the utilization of visible light was enhanced due to the surface plasmon resonance effect of Ag and Pt in the visible region; (ii) Ag nanoparticles mainly acted as electron acceptors to restrain the recombination of photogenerated electron-hole pairs under visible light irradiation; and (iii) Pt nanoparticles acted as electron cocatalysts to further suppress the recombination of photogenerated electron-hole pairs. The photocatalytic performance of Ag0.7Pt0.3/Bi4Ti3O12 was superior to that of Ag/Bi4Ti3O12 and Pt/Bi3Ti4O12 owing to the synergistic effect between Ag and Pt nanoparticles.

Promoted photocarriers transfer and increased active sites for optimal CO2–to–CH4 photoconversion via the modification of atomically dispersed transition metal ions in CdZnS nanocrystals

2021 ◽  
Author(s):  
Haibo Huang ◽  
Hui-Ying Zhang ◽  
Feng-Ying Cai ◽  
Y Li ◽  
Jian Lü ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Conversion Rate ◽  
Active Sites ◽  
Transition Metal Ions ◽  
Co2 Photoreduction

Atomically dispersed transition metal ions doped CdZnS nanocrystals were synthesized to delicately tune the selectivity of CO2 photoreduction towards CH4, by which the CZS–Cu2+ achieved an excellent CO2–to–CH4 conversion rate...

scholarly journals Tunable electronic and optical properties of a BAs/As heterostructure by vertical strain and external electric field

RSC Advances ◽  
2021 ◽  
Vol 11 (35) ◽  
pp. 21824-21831
Author(s):  
X. Q. Deng ◽  
R. Q. Sheng ◽  
Q. Jing
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
External Electric Field ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Electronic And Optical Properties ◽  
Vertical Strain

The CBM (VBM) of the heterostructure is mainly contributed by the BAs (arsenene), which will favor the separation of photogenerated electron–hole pairs.

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