Titania-based heterogeneous photocatalysis. Materials, mechanistic issues, and implications for environmental remediation

2001 ◽  
Vol 73 (12) ◽  
pp. 1849-1860 ◽  
Author(s):  
Krishnan Rajeshwar ◽  
C. R. Chenthamarakshan ◽  
Scott Goeringer ◽  
Miljana Djukic
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Hexavalent Chromium ◽  
Environmental Remediation ◽  
Catalytic Properties ◽  
Heterogeneous Photocatalysis ◽  
The Other ◽  
Tio2 Surface ◽  
Tio2 Sample

Using hexavalent chromium [Cr(VI)] and methylene blue (MB) as model substrates, we discuss three aspects of TiO2-based heterogeneous photocatalysis. We show first that a given TiO2 sample may not be simultaneously optimal for photocatalytically driving the reduction of Cr(VI) and the oxidation of MB. We further show that a TiO2 sample that strongly adsorbs either of these substrates in the dark is not optimal as a photocatalyst. The other two aspects concern circumventing the rather poor surface catalytic properties and visible light photoresponse of TiO2, respectively. Strategies revolving around the visible light photoexcitation of the substrate itself and metal-modification of the TiO2 surface, are described as possible solutions.

scholarly journals Hydrogenated Amorphous TiO2−x and Its High Visible Light Photoactivity

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2801
Author(s):  
Guang Feng ◽  
Mengyun Hu ◽  
Shuai Yuan ◽  
Junyi Nan ◽  
Heping Zeng
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Rhodamine B ◽  
Environmental Remediation ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Ros Generation ◽  
Electronic Band ◽  
Amorphous Tio2 ◽  
Hydrogenated Amorphous

Hydrogenated crystalline TiO2 with oxygen vacancy (OV) defect has been broadly investigated in recent years. Different from crystalline TiO2, hydrogenated amorphous TiO2−x for advanced photocatalytic applications is scarcely reported. In this work, we prepared hydrogenated amorphous TiO2−x (HA-TiO2−x) using a unique liquid plasma hydrogenation strategy, and demonstrated its highly visible-light photoactivity. Density functional theory combined with comprehensive analyses was to gain fundamental understanding of the correlation among the OV concentration, electronic band structure, photon capturing, reactive oxygen species (ROS) generation, and photocatalytic activity. One important finding was that the narrower the bandgap HA-TiO2−x possessed, the higher photocatalytic efficiency it exhibited. Given the narrow bandgap and extraordinary visible-light absorption, HA-TiO2−x showed excellent visible-light photodegradation in rhodamine B (98.7%), methylene blue (99.85%), and theophylline (99.87) within two hours, as well as long-term stability. The total organic carbon (TOC) removal rates of rhodamine B, methylene blue, and theophylline were measured to 55%, 61.8%, and 50.7%, respectively, which indicated that HA-TiO2−x exhibited high wastewater purification performance. This study provided a direct and effective hydrogenation method to produce reduced amorphous TiO2−x which has great potential in practical environmental remediation.

scholarly journals PREPARATION OF TEMPO-CELLULOSE NANOFIBER/ZINC OXIDE AS ANTIMICROBIAL AND METHYLENE BLUE PHOTO-DEGRADING NANOCOMPOSITE

2021 ◽  
Vol 55 (3-4) ◽  
pp. 365-373
Author(s):  
MOHAMED EL-SAKHAWY ◽  
AHMED SALAMA ◽  
AHMED K. EL-ZIATY ◽  
HAZEM HASSAN
Keyword(s):  
Methylene Blue ◽  
Zinc Oxide ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Environmental Remediation ◽  
Organic Dyes ◽  
Cellulose Nanofibers ◽  
Light Irradiation ◽  
Order Kinetic ◽  
Catalytic Material

"Photo-catalytic degradation of organic dyes in aquatic environments under visible light irradiation affords an efficient and economic technique for environmental remediation. TEMPO-oxidized cellulose nanofibers/zinc oxide nanocomposite (TEMPO-CNF/ZnO) was prepared through oxidation of cellulose pulp, followed by zinc oxide precipitation in the presence of oxidized fibers. TEMPO-CNF/ZnO was characterized by different techniques. The degradation rate of methylene blue (MB) by TEMPO-CNF/ZnO was gradually increased with increasing pH and the degradation reached 86% within 340 minutes at pH 7. The kinetic study showed that the pseudo-first-order kinetic best fitted the photo-catalytic process. A mechanism was proposed for the degradation of MB using TEMPO-CNF/ZnO under visible light irradiation. TEMPO-CNF/ZnO showed high antibacterial activity against S. aureus and E. coli. Thus, the TEMPO-CNF/ZnO nanocomposite has been demonstrated to be an effective photo-catalytic material for degrading MB under visible light irradiation."

scholarly journals Fabrication of Rh-doped TiO2 nanofibers for Visible Light Degradation of Rhodamine B

2011 ◽  
Vol 1352 ◽  
Author(s):  
Emilly A. Obuya ◽  
William Harrigan ◽  
Tim O’Brien ◽  
Dickson Andala ◽  
Eliud Mushibe ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Environmental Remediation ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Organic Pollutant ◽  
Heterogeneous Photocatalysis ◽  
Tio2 Nanofibers ◽  
Visible Light Degradation ◽  
Surface Modified

ABSTRACTThe synthesis and application of environmentally benign, efficient and low cost heterogeneous catalysts is increasingly important for affordable and clean chemical technologies. Nanomaterials have been proposed to have new and exciting properties relative to their bulk counterparts due to the quantum level interactions that exist at nanoscale. These materials also offer enormous surface to volume ratios that would be invaluable in heterogeneous catalysis. Recent studies point at titanium dioxide nanomaterials as having strong potential to be applied in heterogeneous photocatalysis for environmental remediation and pollution control. This work reports the use of surface modified anatase TiO2 nanofibers with rhodium (Rh) nanoparticles in the photodegradation of rhodamine B (RH-B), an organic pollutant. The dimensions of TiO2 nanofibers were 150±50 nm in diameter and the size of the Rh nanoparticles was ~5 nm. The Rh-doped TiO2 catalyst exhibited an enhanced photocatalytic activity in photodegradation of rhodamine B under visible light irradiation, with 95 % degradation within 180 minutes reaction time. Undoped TiO2 did not show any notable phocatalytic activity under visible light.

scholarly journals MoS2/Cu/TiO2 nanoparticles: synthesis, characterization and effect on photocatalytic decomposition of methylene blue in water under visible light

2018 ◽  
Vol 2017 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Desireé M. de los Santos ◽  
Sara Chahid ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Teresa Aguilar ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Visible Region ◽  
Pure Tio2 ◽  
Photocatalytic Decomposition ◽  
Tio2 Sample ◽  
X Ray ◽  
Vis Spectroscopy

Abstract Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO2 was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO2 and x%MoS2/Cu/TiO2 nanoparticles were prepared, where x is the theoretical quantity of MoS2 added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO2 structure was doped with the Mo6+ and Cu2+ ions in the position of the Ti4+. The x%MoS2/Cu/TiO2 samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO2 sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS2/Cu/TiO2) there were significant increases of up to 93% in the photocatalytic activity.

Efficient Visible-Light-Driven Reduction of Hexavalent Chromium Catalyzed by Conjugated Organic Species Modified Hourglass-type Phosphomolybdate Hybrids

CrystEngComm ◽  
2022 ◽  
Author(s):  
Haoxue Bi ◽  
Xiao-Yu Yin ◽  
Xiu-Juan Zhang ◽  
Yuan-Yuan Ma ◽  
Zhangang Han
Keyword(s):  
Wastewater Treatment ◽  
Visible Light ◽  
Hexavalent Chromium ◽  
Environmental Remediation ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Organic Species ◽  
Structure Activity ◽  
Visible Light Driven ◽  
Relationship Of

The exploration of stable and efficient visible-light-driven photocatalyst for wastewater treatment has been recognized as one of the most challenging issues in environmental remediation. To reveal the structure-activity relationship of...

scholarly journals Preparation of TiO2-Fullerene Composites and Their Photocatalytic Activity under Visible Light

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ken-ichi Katsumata ◽  
Nobuhiro Matsushita ◽  
Kiyoshi Okada
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Uv Light ◽  
Solution Process ◽  
The Other ◽  
Photogenerated Electrons ◽  
Ft Ir

The development of visible light-sensitive photocatalytic materials is being investigated. In this study, the anatase and rutile-C60composites were prepared by solution process. The characterization of the samples was conducted by using XRD, UV-vis, FT-IR, Raman, and TEM. The photocatalytic activity of the samples was evaluated by the decolorization of the methylene blue. From the results of the Raman, FT-IR, and XRD, the existence of the C60was confirmed in the samples. The C60was modified on the anatase or rutile particle as a cluster. The C60didn't have the photocatalytic activity under UV and visible light. The anatase and rutile-C60composites exhibited lower photocatalytic activity than the anatase and rutile under UV light. The anatase-C60exhibited also lower activity than the anatase under visible light. On the other hand, the rutile-C60exhibited higher activity than the rutile under visible light. It is considered that the photogenerated electrons can transfer from the C60to the rutile under visible light irradiation.

scholarly journals Improved Visible-Light Photocatalytic Activity of g-C3N4/CuWO4 Nanocomposite for Degradation of Methylene Blue

Proceedings ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 43
Author(s):  
Afsaneh Rashidizadeh ◽  
Hossein Ghafuri ◽  
Zeynab Rezazadeh
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Solar Energy ◽  
Visible Light ◽  
Environmental Remediation ◽  
High Efficiency ◽  
Hydrothermal Process ◽  
Co2 Reduction ◽  
High Rate ◽  
Visible Light Driven

In recent years, heterogeneous semiconductor photocatalysts have attracted great attention in the arena of environmental remediation and solar energy conversion; because, sunlight energy is a renewable, cheap, and accessible source of energy and also converting solar energy to chemical energy can be declined the energy crisis and global warming. Development of visible light heterogeneous photocatalysts with high efficiency and chemical stability is important for catalysis researchers. Among different types of semiconductor material, polymeric graphitic carbon nitride (g-C3N4) with a medium band gap of about 2.7 eV has been widely applied in photodegradation of organic pollutants, water splitting, CO2 reduction, solar cells, energy storage, and organic synthesis. Unfortunately, due to the high rate recombination of photoinduced carriers, the photocatalytic performance of the bare g-C3N4 is still poor. Hence, many strategies including metal doping, noble metal deposition, and coupling with semiconductor composites have been employed to modify g-C3N4. Herein, we report the synthesis of g-C3N4/CuWO4 nanocomposite via a hydrothermal process. The prepared visible-light-driven nanocomposite exhibited an enhanced photocatalytic activity compared with bare g-C3N4 for the degradation of methylene blue (MB) under LED light irradiation.

Visible Light Active Ce-doped TiO2 Nanoparticles for Photocatalytic Degradation of Methylene Blue

2016 ◽  
Vol 13 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Rani P. Barkul ◽  
Farah-Naaz A. Shaikh ◽  
Sagar D. Delekar ◽  
Meghshyam K. Patil
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Doped Tio2 ◽  
Visible Light Active
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