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.

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 Photocatalytic activity of CaTaO2N nanocrystals obtained from a hydrothermally synthesized oxide precursor

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Morphological Properties ◽  
Soft Chemistry ◽  
Co Catalyst ◽  
Surface Areas ◽  
Oxide Precursor ◽  
Photocatalytic Activities ◽  
Specific Surface Areas

Highly crystalline CaTaO2N nanoparticles possessing large specific surface areas were investigated as photocatalysts for the decomposition of methyl orange. Two different Ca2Ta2O7 precursors were synthesized by classical solid state synthesis and a hydrothermal soft-chemistry approach, respectively. In both cases, nitridation was carried out by thermal ammonolysis. The obtained CaTaO2N samples were compared with respect to their optical, thermal and morphological properties as well as their photocatalytic activities. In particular, the influence of ammonolysis temperature on the photocatalytic properties was studied. Using hydrothermally synthesized Ca2Ta2O7, phase pure CaTaO2N was obtained already at a relatively low ammonolysis temperature of 860 °C. Morphological investigations show that the CaTaO2N samples from the hydrothermally synthesized precursor consist of single-crystalline particles of 45 to 70 nm diameter with high specific surface areas between 12 and 19 m2 g-1, depending on ammonolysis temperature. A considerable photocatalytic activity for methyl orange degredation was found for the nanoscaled CaTaO2N particles prepared at lower ammonolysis temperatures. Using CoOx as co-catalyst, a further strong enhancement of the methyl orange decomposition by a factor 5-10 was achieved.

Non-Noble Metallic Cu with Three Different Roles in Cu doped ZnO/Cu/g-C3N4 Heterostructure for Enhanced Z-Scheme Photocatalytic Activity

2021 ◽  
Author(s):  
Mohammed Abdullah Bajiri ◽  
Abdo Hezam ◽  
Namratha Keerthiraj ◽  
Basheer M. Al-Maswari ◽  
Halehatty S. Bhojya Naik ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Metal Oxides ◽  
Hydrothermal Method ◽  
Co Catalyst ◽  
Doped Zno

Doping, co-catalyst, and Z-scheme configuration are three potential approaches to enhance the photocatalytic activity of metal oxides. Cu doped ZnO/Cu/g-C3N4 heterostructure is prepared using the calcination-hydrothermal method. The successful fabrication...

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.

Effect of Ag Co-catalyst on TiO2–Cu2O nanocomposites structure and apparent visible photocatalytic activity

2020 ◽  
Vol 260 ◽  
pp. 110175 ◽  
Author(s):  
Dávidné Nagy ◽  
Cong Chao ◽  
Bartosz Marzec ◽  
Fabio Nudelman ◽  
Maria-Chiara Ferrari ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Co Catalyst ◽  
Visible Photocatalytic Activity

Comparison of Adsorption Capability and Photocatalytic Activity for Methylene Blue Decomposition of LiInO2 with NaInO2

2006 ◽  
Vol 317-318 ◽  
pp. 819-822
Author(s):  
Jun Hu Wang ◽  
Toru Nonami
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Fine Particles ◽  
Composite Particles ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Co Catalyst ◽  
Photocatalytic Activities ◽  
Adsorption Capability

In the present study, Pt, NiO, and RuO2 fine particles as co-catalyst were loaded on the LiInO2 surface by different methods for enhancing its adsorption capability and photocatalytic activity for methylene blue dye (MB) decomposition. Clear adsorption capability and marked photocatalytic activity for MB decomposition were confirmed on the co-catalyst loaded LiInO2 composite particles. Comparing with that of LiINO2, the previously reported NaInO2 photocatalyst had stronger adsorption capability and higher photocatalytic activity. However, the adsorption capabilities and the photocatalytic activities were separately in the same order of RuO2/AInO2 > Pt/AInO2 > AInO2 > NiO/AInO2 and Pt/LiInO2 > RuO2/LiInO2 > NiO/LiInO2 > LiInO2 for the two promising AInO2 (A = Li+ or Na+) photocatalyst.

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