Effects of the silver nanodots on the photocatalytic activity of mixed‐phase TiO 2

2021 ◽  
Author(s):  
Nikola Tasić ◽  
Jovana Ćirković ◽  
Vesna Ribić ◽  
Milan Žunić ◽  
Aleksandra Dapčević ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Mixed Phase ◽  
Silver Nanodots

Cuprous Oxide Films Deposition by Mid-Frequency Magnetron Sputtering and Their Photocatalytic Activity under Visible Light

NANO ◽  
2021 ◽  
Author(s):  
Z. X. Mu ◽  
H. Li ◽  
X. N. Deng
Keyword(s):  
Photocatalytic Activity ◽  
Magnetron Sputtering ◽  
Visible Light ◽  
Cuprous Oxide ◽  
Deposition Time ◽  
Visible Region ◽  
Mixed Phase ◽  
Photocatalytic Properties ◽  
Oxygen Flow ◽  
Photocatalytic Films

Cuprous oxide (Cu2O) has attracted much attention as a photocatalytic material. In this paper, the mid-frequency reactive magnetron sputtering method was used to prepare Cu2O films on glass slides, and the effects of oxygen flow and deposition time on the structures, morphologies and photocatalytic properties of the films were studied. The results show that the films prepared by this method have smooth surfaces and good absorptivity in the visible region. As the oxygen flow increases, the films transit from the mixed-phase of Cu and Cu2O to the single-phase of Cu2O. When the oxygen flow continues to increase, the films change to a mixed-phase of Cu4O3 and Cu2O. The photocatalytic decolorization of methyl orange under visible light irradiation conditions was used to assess the photocatalytic properties of the prepared films. When the oxygen flow is 6[Formula: see text]sccm and the deposition time is 15[Formula: see text]min, the film exhibits the best photocatalytic activity. Finally, the Mulliken electronegativity theory was used to explain the photocatalytic mechanism of Cu2O. This study confirmed the feasibility of preparing Cu2O photocatalytic films by magnetron sputtering, and provided the experimental basis for the subsequent study of Cu2O photocatalytic films.

Preparation and Photocatalytic Activity of Mixed Phase Anatase/rutile TiO2 Nanoparticles for Phenol Degradation

2014 ◽  
Vol 70 (2) ◽  
Author(s):  
Mohamad Azuwa Mohamed ◽  
Wan Norharyati Wan Salleh ◽  
Juhana Jaafar ◽  
Norhaniza Yusof
Keyword(s):  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
High Performance ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Chemical Properties ◽  
Mixed Phase ◽  
Rutile Tio2 ◽  
Physico Chemical ◽  
Degussa P25

The evolution of desirable physico-chemical properties in high performance photocatalyst materials involves steps that must be carefully designed, controlled, and optimized. This study investigated the role of key parameter in the preparation and photocatalytic activity analysis of the mixed phase of anatase/rutile TiO2 nanoparticles, prepared via sol-gel method containing titanium-n-butoxide Ti(OBu)4 as a precursor material, nitric acid as catalyst, and isopropanol as solvent. The prepared TiO2 nanoparticles were characterized by means of XRD, SEM, and BET analyses, and UV-Vis-NIR spectroscopy. The results indicated that the calcination temperature play an important role in the physico-chemical properties and photocatalytic activity of the resulting TiO2 nanoparticles. Different calcination temperatures would result in different composition of anatase and rutile. The photocatalytic activity of the prepared mixed phase of anatase/rutile TiO2 nanoparticles was measured by photodegradation of 50 ppm phenol in an aqueous solution. The commercial anatase from Sigma-Aldrich and Degussa P25 were used for comparison purpose. The mixed phase of anatase/rutile TiO2 nanoparticles (consists of 38.3% anatase and 61.7% rutile) that was prepared at 400°C exhibited the highest photocatalytic activity of 84.88% degradation of phenol. The result was comparable with photocatalytic activity demonstrated by Degussa P25 by 1.54% difference in phenol degradation. The results also suggested that the mixed phase of anatase/rutile TiO2 nanoparticles is a promising candidate for the phenol degradation process. The high performance of photocatalyst materials may be obtained by adopting a judicious combination of anatase/rutile and optimized calcination conditions.

scholarly journals Black and white anatase, rutile and mixed forms: band-edges and photocatalytic activity

2019 ◽  
Vol 55 (4) ◽  
pp. 533-536 ◽  
Author(s):  
Xuemei Zhou ◽  
Ewa Wierzbicka ◽  
Ning Liu ◽  
Patrik Schmuki
Keyword(s):  
Photocatalytic Activity ◽  
Mixed Phase ◽  
Co Catalyst ◽  
Black And White

Polymorphs of “black” TiO2 in their mixed phase forms provide efficient junctions for photocatalytic H2 generation in absence of any external co-catalyst.

Photocatalytic activity and antibacterial efficacy of UVA-treated titanium oxides

2020 ◽  
Vol 35 (4-5) ◽  
pp. 500-514
Author(s):  
Haden Andrew Johnson ◽  
Randall Scott Williamson ◽  
Mary Marquart ◽  
Joel David Bumgardner ◽  
Amol V Janorkar ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Pure Titanium ◽  
Antimicrobial Properties ◽  
Bacterial Attachment ◽  
Mixed Phase ◽  
Titanium Oxides ◽  
Commercially Pure Titanium ◽  
Mixed Acid ◽  
Uva Irradiation ◽  
Titanium Grade

Studies have shown ultraviolet-A (UVA) irradiation of crystalline titanium oxides leads to the production of reactive oxygen species (ROS) via a photocatalytic process. The ROS exhibit antimicrobial properties that may be of benefit in preventing bacterial attachment to implant devices. Recent studies have suggested a potential benefit of mixed anatase and rutile oxides and dopants on the photocatalytic properties of titanium oxides. The goal of this work was to compare the photocatalytic activity of different anodized commercially pure titanium grade 4 (CPTi4) surfaces. CPTi4 specimens were anodized in three mixed-acid electrolytes to create crystalline oxide surfaces that were either primarily anatase, primarily rutile, or a combination of anatase and rutile. Additionally, the primarily anatase and combination oxides incorporated some phosphorous from the phosphoric acid component in the electrolyte. The photocatalytic activity of the anodized specimens was measured using both methylene blue (MB) degradation assay and comparing the attachment of S. aureus under irradiation with UVA light of differing intensities (1 mW/cm2, 8 mW/cm2, and 23 mW/cm2). Primarily rutile oxides exhibited significantly higher levels of MB degradation after exposure to 1 mW/cm2 UVA lights. Primarily rutile specimens also had the largest reduction in bacterial attachment followed by the mixed phase specimens and the primarily anatase specimens at 1 mW/cm2 UVA lights. Phosphorous-doped, mixed phase oxides exhibited an accelerated MB degradation response during exposure to 8 mW/cm2 and 23 mW/cm2 UVA lights. All anodized and unanodized CPTi4 groups revealed similar S. aureus attachment at the two higher UVA intensities. Although MB degradation assay and the bacteria attachment assay both confirmed photocatalytic activity of the oxides formed in this study, the results of the MB degradation assay did not accurately predict the oxides performance against S. aureus.

scholarly journals Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1054 ◽  
Author(s):  
Kunlei Wang ◽  
Marcin Janczarek ◽  
Zhishun Wei ◽  
Tharishinny Raja-Mogan ◽  
Maya Endo-Kimura ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Three Dimensional ◽  
Active Phase ◽  
Magnetic Core ◽  
High Photocatalytic Activity ◽  
Mixed Phase ◽  
Mechanism Study ◽  
3D Network ◽  
Commercial Applications ◽  
Continuous Use

Titania photocatalysts have been intensively examined for both mechanism study and possible commercial applications for more than 30 years. Although various reports have already been published on titania, including comprehensive review papers, the morphology-governed activity, especially for novel nanostructures, has not been reviewed recently. Therefore, this paper presents novel, attractive, and prospective titania photocatalysts, including zero-, one-, two-, and three-dimensional titania structures. The 1D, 2D, and 3D titania structures have been mainly designed for possible applications, e.g., (i) continuous use without the necessity of particulate titania separation, (ii) efficient light harvesting (e.g., inverse opals), (iii) enhanced activity (fast charge carriers’ separation, e.g., 1D nanoplates and 2D nanotubes). It should be pointed out that these structures might be also useful for mechanism investigation, e.g., (i) 3D titania aerogels with gold either incorporated inside the 3D network or supported in the porosity, and (ii) titania mesocrystals with gold deposited either on basal or lateral surfaces, for the clarification of plasmonic photocatalysis. Moreover, 0D nanostructures of special composition and morphology, e.g., magnetic(core)–titania(shell), mixed-phase titania (anatase/rutile/brookite), and faceted titania NPs have been presented, due to their exceptional properties, including easy separation in the magnetic field, high activity, and mechanism clarification, respectively. Although anatase has been usually thought as the most active phase of titania, the co-existence of other crystalline phases accelerates the photocatalytic activity significantly, and thus mixed-phase titania (e.g., famous P25) exhibits high photocatalytic activity for both oxidation and reduction reactions. It is believed that this review might be useful for the architecture design of novel nanomaterials for broad and diverse applications, including environmental purification, energy conversion, synthesis and preparation of “intelligent” surfaces with self-cleaning, antifogging, and antiseptic properties.

Explaining the Enhanced Photocatalytic Activity of Degussa P25 Mixed-Phase TiO2Using EPR

2003 ◽  
Vol 107 (19) ◽  
pp. 4545-4549 ◽  
Author(s):  
Deanna C. Hurum ◽  
Alexander G. Agrios ◽  
Kimberly A. Gray ◽  
Tijana Rajh ◽  
Marion C. Thurnauer
Keyword(s):  
Photocatalytic Activity ◽  
Mixed Phase ◽  
Degussa P25

Cetyltrimethylammonium Bromide-Assisted Hydrothermal Synthesis of Mixed-Phase TiO2 Nanorod and its Photocatalytic Activity

2014 ◽  
Vol 918 ◽  
pp. 12-16 ◽  
Author(s):  
Bin Sun ◽  
Xiu Ling Xu ◽  
Guo Wei Zhou
Keyword(s):  
Photocatalytic Activity ◽  
Cetyltrimethylammonium Bromide ◽  
Removal Rate ◽  
Weight Fraction ◽  
Mixed Phase ◽  
Molar Ratio ◽  
Structure Directing Agent ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation ◽  
Degussa P25

TiO2nanorods were successfully fabricated via hydrothermal method using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent. The synthesized samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscope (FESEM). The study showed that as-prepared samples were the mixed crystalline phase of rutile and brookite. The weight fraction of rutile and brookite in the mixed-phase were accurately tuned by changing the concentration of CTAB. The morphology of prepared samples was TiO2nanorods with the diameter of 2530 nm and the length of 80150 nm. The samples for degradation of papermaking wastewater under ultraviolet light irradiation showed better photocatalytic activity than the commercial Degussa P25. HRT-3 prepared from CTAB: TBT molar ratio of 0.48 exhibited the highest photocatalytic activity, achieving 47.2% CODcrremoval rate and 89.5% chroma removal rate under irradiation 12 h.

Unraveling the Photocatalytic Activity of Multiwalled Hydrogen Trititanate and Mixed-Phase Anatase/Trititanate Nanotubes: A Combined Catalytic and EPR Study

2011 ◽  
Vol 115 (5) ◽  
pp. 2302-2313 ◽  
Author(s):  
Stefan Ribbens ◽  
Ignacio Caretti ◽  
Evi Beyers ◽  
Sepideh Zamani ◽  
Evi Vinck ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Mixed Phase
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