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.

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.

Photocatalytic Properties of α-Bi2O3 Nanoneedle Array Synthesized by Hydrothermal Method

2011 ◽  
Vol 181-182 ◽  
pp. 332-335 ◽  
Author(s):  
H.Y. Wang ◽  
Y.C. Yang ◽  
L. Le ◽  
Y. Liu ◽  
J.H. Wei ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Hydrothermal Method ◽  
Visible Light Irradiation ◽  
Narrow Band ◽  
Light Irradiation ◽  
Nanoneedle Array ◽  
Special Morphology ◽  
Array Structures

Pureα-Bi2O3with nanoneedle array structure was synthesized directly by hydrothermal method. The optic absorption of theα-Bi2O3paricles was cut off at ~483 nm and the band gap of theα-Bi2O3was estimated to be 2.57 eV. The photocatalytic activity of theα-Bi2O3samples was higher than TiO2under a visible light irradiation. As a conclusion, relative narrow band gap ofα-Bi2O3nanoneedle array compared to anatase and the special morphology of nanoneedle array structures may improve the photocatalytic activity in visible light irradiation.

scholarly journals Enhanced Photocatalytic Degradation of Phenol Using Urchin-Like ZnO Microrod-Reduced Graphene Oxide Composite under Visible-Light Irradiation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Phenol Degradation ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Light Illumination ◽  
Order Kinetic ◽  
Phenol Solution ◽  
Vis Spectroscopy

In this study, visible-light-driven ZnO microrod-rGO heterojunction composites were successfully synthesized via a facile and scalable hydrothermal process. The prepared photocatalyst heterojunction was examined using different techniques including XRD, SEM, FTIR, UV-Vis spectroscopy, and TGA to reveal their crystal phase, morphology, and other optical properties. The photocatalytic performance of the obtained ZnO-rGO composites was measured by the photodegradation of phenol under visible light illumination. The addition of graphene over the catalyst exhibited an enhanced photocatalytic activity for phenol degradation due to its high surface area and decreasing rate of electron-hole separation. Kinetic studies proved that the degradation of phenol process happened by following the pseudo-first-order kinetic model. The effective conditions for degradation of phenol using ZnO-rGO composite were 0.2 g L-1catalyst dose, pH -4, and initial concentration 20 ppm of phenol solution. Comparing with ZnO microrods, the heterojunction composite degraded the organic pollutants of phenol solution up to 84.2% of efficiency displaying the highest photocatalytic activity, whereas urchin-like ZnO catalyst exhibited much less photocatalytic activity for phenol degradation under visible light irradiation. This result envisages immense properties, showing a great potential industrial application for the removal of phenolic wastewater.

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

Preparation and characterization of SiO2/BiOX (X = Cl, Br, I) films with high visible-light activity

RSC Advances ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 4918-4925 ◽  
Author(s):  
Fan Shen ◽  
Li Zhou ◽  
Jiajia Shi ◽  
Mingyang Xing ◽  
Jinlong Zhang
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Sol Gel ◽  
Layered Structures ◽  
Light Irradiation ◽  
Gel Method ◽  
Light Activity

SiO2/BiOX (X = Cl, Br, I) thin films with layered structures were prepared using a convenient sol–gel method. The films show a high and stable photocatalytic activity under visible-light irradiation.

Co2+ and Ho3+ doped CuS nanocrystals with improved photocatalytic activity under visible light irradiation

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42581-42588 ◽  
Author(s):  
Zahra Hosseinpour ◽  
Sara Hosseinpour ◽  
Malik Maaza ◽  
Alice Scarpellini
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Hydrothermal Method ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Light Irradiation ◽  
Gap Values

Co2+ and Ho3+ doped CuS nanostructures have been synthesized by a hydrothermal method. The nature of dopants influence the morphology, photocatalytic performance and the band gap values.

scholarly journals Photocatalytic Hydrogen Production from Water on Ga, Sn-Doped ZnS under Visible Light Irradiation

2014 ◽  
Vol 925 ◽  
pp. 200-204
Author(s):  
Leny Yuliati ◽  
Melody Kimi ◽  
Mustaffa Shamsuddin
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Absorption Edge ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Production ◽  
Gap Energy

Zinc sulfide (ZnS) has been reported to act as a photocatalyts to reduce water to hydrogen. However, ZnS could not work under visible light irradiation due to its large band gap energy. In order to improve the performance of ZnS, Ga and Sn were doped to ZnS. The series of Ga (0.1),Sn (x)-ZnS with various amounts of Sn (x) was prepared by hydrothermal method. XRD patterns suggested that the addition of Ga might reduce the crystallinity of ZnS, suggesting that Ga might inhibit the crystal growth or agglomeration of ZnS. On the other hand addition of Sn did not much affect the structure of the Ga (0.1)-ZnS. The DR UU-visible spectra confirmed the red shift of the absorption edge with the addition of Ga due to the reduced band gap energy, while the addition of Sn did not much shift the absorption edge of the Ga (0.1)-ZnS to longer wavelength. FESEM images showed that all the prepared samples have sphere-shaped particles and no remarkable change was observed with the addition of Ga or Sn. The photocatalytic hydrogen production from water was carried out at room temperature in the presence of sacrificial agent under visible light irradiation. While ZnS did not show activity under visible light, all the prepared Ga (0.1)-ZnS and Ga (0.1),Sn (x)-ZnS samples exhibited photocatalytic activity for hydrogen production. The highest hydrogen production was achieved on Ga (0.1),Sn (0.01)-ZnS, which activity was ca. three times higher than that of the single doped Ga (0.1)-ZnS. This study clearly showed that Sn acted as a good co-dopant to increase the photocatalytic activity of Ga (0.1)-ZnS for hydrogen production from water under visible light irradiation.

scholarly journals Titania photocatalysis through two-photon band-gap excitation with built-in rhodium redox mediator

2015 ◽  
Vol 51 (2) ◽  
pp. 298-301 ◽  
Author(s):  
Joanna Kuncewicz ◽  
Bunsho Ohtani
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Redox Mediator ◽  
Redox Couple ◽  
Light Irradiation ◽  
Excitation Mechanism ◽  
Oxidative Decomposition ◽  
Two Photon

Titania particles modified with an extremely small amount (<0.01 mol%) of a rhodium species exhibited photocatalytic activity for the oxidative decomposition of acetaldehyde in air under visible-light irradiation. The reaction proceeded via a two-photon band-gap excitation mechanism with a built-in Rh(III)–Rh(IV) redox couple.

Sign in / Sign up

Export Citation Format

Share Document