scholarly journals Preparation and Characterization of Tubelike g-C3N4/Ag3PO4 Heterojunction with Enhanced Visible-Light Photocatalytic Activity

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1373
Author(s):  
Xin Yan ◽  
Yuanyuan Wang ◽  
Bingbing Kang ◽  
Zhuo Li ◽  
Yanhui Niu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Close Contact ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Dye Wastewater ◽  
Potential Threat ◽  
High Quantum Efficiency ◽  
Photocatalytic Ability

Water pollution caused by dye wastewater is a potential threat to human health. Using photocatalysis technology to deal with dye wastewater has the advantages of strong purification and no secondary pollution, so it is greatly significant to look for new visible-light photocatalysts with high photocatalytic ability for dye wastewater degradation. Semiconductor photocatalyst silver phosphate (Ag3PO4) has high quantum efficiency and photocatalytic degradation activity. However, Ag3PO4 is prone to photoelectron corrosion and becomes unstable during photocatalysis, which severely limits its application in this field. In this study, a tubelike g-C3N4/Ag3PO4 heterojunction was constructed by the chemical precipitation method. An Ag3PO4 nanoparticle was loaded onto the surface of the tubelike g-C3N4, forming close contact. The photocatalytic activity of the photocatalyst was evaluated by the degradation of RhB under visible-light irradiation. The tubelike g-C3N4/Ag3PO4-5% heterojunction exhibited optimal photocatalytic performance. In an optimal process, the degradation rate of the RhB is 90% under visible-light irradiation for 40 min. The recycling experiment showed that there was no apparent decrease in the activity of tubelike g-C3N4/Ag3PO4-5% heterojunction after five consecutive runs. A possible Z-type mechanism is proposed to explain the high activity and stability of the heterojunction.

Enhanced photocatalytic activity of a pine-branch-like ternary CuO/CuS/ZnO heterostructure under visible light irradiation

2019 ◽  
Vol 43 (28) ◽  
pp. 11342-11347 ◽  
Author(s):  
Fa Cao ◽  
Zhihu Pan ◽  
Xiaohong Ji
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Organic Dyes ◽  
Light Irradiation ◽  
Photocatalytic Ability ◽  
Visible Light Photocatalytic

A pine-branch-like ternary CuO/CuS/ZnO heterostructure exhibits enhanced visible light photocatalytic ability toward organic dyes.

scholarly journals Recent Advances in Doped Bi2O3 and its Photocatalytic Activity: A Review

2022 ◽  
Vol 9 (1) ◽  
pp. 216-230
Author(s):  
Bella Aprimanti Utami ◽  
Heri Sutanto ◽  
Eko Hidayanto
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Energy Gap ◽  
Light Irradiation ◽  
High Electron ◽  
Photocatalytic Ability ◽  
As Doping ◽  
Electron Hole Pair ◽  
Defect Recognition

Bismuth Oxide (Bi2O3) has a very promising photocatalytic ability to degrade waste pollutants under visible light irradiation because it has a small energy gap of around 2.85-2.58 eV. Although it has excellent potential as a photocatalyst, Bi2O3 has the disadvantage of a high electron-hole pair recombination rate, which will reduce its photocatalytic activity. To overcome these problems, surface modifications, defect recognition, or doping of Bi2O3 are carried out to obtain a more effective and efficient photocatalyst to degrade waste pollutants under visible light irradiation. Several studies by researchers have been described for the modification of Bi2O3 by doping. Various types of doping are given, such as doping in elements or doping in the form of compounds to form composites. Based on several studies that have been described, appropriate doping has been shown to increase the photocatalytic activity of Bi2O3. Keywords: Bi2O3, Photocatalyst, Doping

Construction of ZnxCd1−xS/CeO2 composites for enhanced photocatalytic activity and stability by chemical precipitation method

2021 ◽  
pp. 2150334
Author(s):  
Yi-Feng Chai ◽  
Zhong-Hua Zhu ◽  
Ming-Wei Liu ◽  
Jing Zeng ◽  
Gui-Fang Huang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Uv Light ◽  
Chemical Precipitation ◽  
Charge Carriers ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Uv Light Irradiation

Development photoinduced photocatalysts is a significant approach to improve photocatalytic activity and stability. Herein, we successfully prepared Zn[Formula: see text]Cd[Formula: see text]S/CeO2 composites by a facile method. It is found that the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 composites show significant enhancement in photocatalytic activity for methyl orange (MO) degradation under visible and UV light irradiation. The degradation efficiency reaches up to 3.7 times higher than that of pure CeO2 under visible light irradiation. Moreover, the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 samples have almost no loss of photocatalytic activity after five recycles, indicating good photocatalytic stability of the samples. The attractive photocatalytic activity of the Zn[Formula: see text]Cd[Formula: see text]S/CeO2 samples could be attributed to the robust charge carriers transfer and separation.

Enhanced Photocatalytic Activity by Silver-Modified Bismuth Vanadate

2017 ◽  
Vol 757 ◽  
pp. 88-92
Author(s):  
Cheewita Suwanchawalit ◽  
Kamonchanok Roongraung ◽  
Supat Buddee ◽  
Sumpun Wongnawa ◽  
Avinash Patil
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Visible Region ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Blue Dye ◽  
Vis Spectroscopy

Silver-modified bismuth vanadate (Ag-BiVO4) photocatalysts were easily prepared via the co-precipitation method. The effects of silver contents on the chemical properties of BiVO4 were evaluated. The prepared Ag-BiVO4 samples were characterized by several techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffused reflectance UV-Vis spectroscopy (DRS). The mixed phase of monoclinic scheetlite structure and characteristic peaks of silver particles were found. Silver contents strongly affect the morphology of the prepared Ag-BiVO4 samples. DRS spectra revealed that the synthesized Ag-BiVO4 samples exhibited strong absorption in the visible region. The absorption in the visible zone is responsible for the high photocatalytic activity of Ag-BiVO4 under visible light irradiation. The photocatalytic degradation of methylene blue under visible light irradiation was studied using the BiVO4 as photocatalysts. The photocatalytic results reveal that the prepared Ag-BiVO4 samples could degrade the methylene blue dye.

scholarly journals Thickness Dependent on Photocatalytic Activity of Hematite Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yen-Hua Chen ◽  
Kuo-Jui Tu
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Film Thickness ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Hexagonal Structure ◽  
Light Irradiation ◽  
Light Illumination ◽  
Photocatalytic Ability

Hematite (Fe2O3) thin films with different thicknesses are fabricated by the rf magnetron sputtering deposition. The effects of film thicknesses on the photocatalytic activity of hematite films have been investigated. Hematite films possess a polycrystalline hexagonal structure, and the band gap decreases with an increase of film thickness. Moreover, all hematite films exhibit good photocatalytic ability under visible-light irradiation; the photocatalytic activity of hematite films increases with the increasing film thickness. This is because the hematite film with a thicker thickness has a rougher surface, providing more reaction sites for photocatalysis. Another reason is a lower band gap of a hematite film would generate more electron-hole pairs under visible-light illumination to enhance photocatalytic efficiency. Experimental data are well fitted with Langmuir-Hinshelwood kinetic model. The photocatalytic rate constant of hematite films ranges from 0.052 to 0.068 min-1. This suggests that the hematite film is a superior photocatalyst under visible-light irradiation.

scholarly journals High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

2014 ◽  
Vol 5 ◽  
pp. 587-595 ◽  
Author(s):  
Leny Yuliati ◽  
Melody Kimi ◽  
Mustaffa Shamsuddin
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Ag Doping ◽  
Light Region ◽  
Co Precipitation

Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation. Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation. Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

Synthesis of Bi2O3/Ag3Po4 Composites and their Photocatalytic Activities under Visible Light Irradiation

2015 ◽  
Vol 1112 ◽  
pp. 163-167 ◽  
Author(s):  
Uyi Sulaeman ◽  
Estri Yunari ◽  
Ponco Iswanto ◽  
Shu Yin ◽  
Tsugio Sato
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Body Centered Cubic ◽  
Bet Specific Surface Area ◽  
Photocatalytic Activities ◽  
Co Precipitation ◽  
Rhodamin B

The Bi2O3/Ag3PO4 composites consisting of the monoclinic α-Bi2O3 and body-centered cubic Ag3PO4 were successfully synthesized by grinding Ag3PO4 and Bi2O3 mixtures in ethanol using an agate mortar, followed by calcination at 500°C for 5 hours, where the Ag3PO4 was synthesized by co-precipitation method using AgNO3 and NaH2PO4.2H2O as starting materials. The Bi2O3 content in the composite materials changed from 5 to 25 mol.%. The composites were characterized using XRD, DRS and BET specific surface area. The photocatalytic activities were evaluated using Rhodamin B degradation under visible light irradiation of blue LED (λ = 445 nm). The highest photocatalytic activities could be obtained at 5 mol.% Bi2O3 in Bi2O3/Ag3PO4 composite. The enhanced photocatalytic activity could be attributed to the effective separation of hole (h+) and electron (e-) pairs in the Bi2O3/Ag3PO4 composite.

Preparation of Ag3PO4/BiOCOOH Composite Photocatalysts with High Photocatalytic Performances Under Visible Light Irradiation

NANO ◽  
2016 ◽  
Vol 11 (09) ◽  
pp. 1650105 ◽  
Author(s):  
Xiaoting Meng ◽  
Xiaofang Cheng ◽  
Dongrong Zhuang ◽  
Shaogui Yang ◽  
Cheng Sun
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Active Role ◽  
Active Species ◽  
Light Irradiation ◽  
Free Radical Scavengers ◽  
Precipitation Method ◽  
X Ray ◽  
Composite Photocatalysts

A series of Ag3PO4/BiOCOOH composite photocatalysts have been successfully synthesized by a simple in situ ion precipitation method. The crystallinity, morphology, microstructure, composition and optical property were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectrophotometer (DRS). The as-prepared catalysts exhibited excellent photocatalytic activity for the degradation of RhB and MB under visible light irradiation, the 2:1 Ag3PO4/BiOCOOH exhibited the best photocatalytic activity. By adding different free radical scavengers, the catalytic mechanism was discussed. In the process of degradation of RhB, holes (h[Formula: see text] is the main active species, [Formula: see text]O[Formula: see text] played a certain active role, [Formula: see text]OH played a small role. In the process of degradation MB, holes (h[Formula: see text] is the main active species too, [Formula: see text]O[Formula: see text] also played a certain active role, [Formula: see text]OH almost does not work.

scholarly journals ZnO Surface Doping to Enhance the Photocatalytic Activity of Lithium Titanate/TiO2 for Methylene Blue Photodegradation under Visible Light Irradiation

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 301-318 ◽  
Author(s):  
Anwar Iqbal ◽  
N. H. Ibrahim ◽  
Nur Ruzaina Abdul Rahman ◽  
K. A. Saharudin ◽  
Farook Adam ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Surface Defects ◽  
Lithium Titanate ◽  
Significant Loss ◽  
Light Irradiation ◽  
Photocatalytic Ability ◽  
Transmission Electron

Wastewater contaminated with dyes produced by textile industries is a major problem due to inadequate treatment prior to release into the environment. In this paper, the ability of ZnO to enhance the interfacial photocatalytic activity of lithium titanate/TiO2 (LTO/TiO2) for the photodegradation of methylene blue (MB) under visible light irradiation (4.38 mW/cm2) was assessed. The ZnO-doped lithium titanate/TiO2 (ZnO/LTO/TiO2) was synthesized using a combination of hydrothermal and wetness impregnation methods. The high-resolution transmission electron microscope (HRTEM) and X-ray Diffraction (XRD) analyses indicate that the ZnO/LTO/TiO2 contain several phases (ZnO, LTO, and TiO2). The adsorption capacity of LTO/TiO2 (70%) was determined to be higher compared to its photocatalytic activity (25%), which is attributed to the strong interaction between the Li and surface oxygen atoms with the MB dye molecules. The introduction of ZnO improved the photocatalytic ability of LTO/TiO2 by 45% and extended the life span of ZnO/LTO/TiO2. The ZnO/LTO/TiO2 can be reused without a significant loss up to four cycles, whereas LTO/TiO2 had reduced adsorption after the second cycle by 30%. The ZnO increased the surface defects and restrained the photo-induced electrons (e−) from recombining with the photo-induced holes (h+). Scavenging tests indicated that the hydroxyl radicals played a major role in the photodegradation of MB, which is followed by electrons and holes.

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