scholarly journals Photocatalytic Decolorization of Methyl Red on Nanoporous Anodic ZrO2 of Different Crystal Structures

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Ewa Wierzbicka ◽  
Karolina Syrek ◽  
Klaudia Mączka ◽  
Grzegorz D. Sulka
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Elevated Temperatures ◽  
Aqueous Electrolyte ◽  
High Surface ◽  
High Surface Area ◽  
Methyl Red ◽  
Self Organized ◽  
Photocatalytic Decolorization ◽  
Perfect Adhesion

High surface area, self-organized nanoporous ZrO2 arrays with perfect adhesion to the Zr substrate were synthesized by anodization in an aqueous electrolyte containing (NH4)2SO4 and NH4F. The obtained semiconductor materials were tested as photocatalysts for decolorization of the methyl red (MR) as a model azo dye pollutant. It was demonstrated that as-synthesized anodic ZrO2 anodic layers are already crystalline and, therefore, do not require further thermal treatment to provide a high photocatalytic performance. However, photocatalytic efficiency could be improved by annealing at a relatively low-temperature of 350 °C. Higher annealing temperatures caused a gradual drop of photocatalytic activity. The photocatalytic behavior was correlated with the crystal phase transformation in anodic ZrO2. It was found that higher photocatalytic activity was observed for the tetragonal phase over the monoclinic phase (predominant at elevated temperatures). It results from the optimal and complex electronic structure of annealed ZrO2 with three different energy states having absorption edges at 2.0, 4.01 and 5.28 eV.

scholarly journals Construction of SnS2–SnO2 heterojunctions decorated on graphene nanosheets with enhanced visible-light photocatalytic performance

2019 ◽  
Vol 75 (6) ◽  
pp. 812-821 ◽  
Author(s):  
Ruting Huang ◽  
Chenghao Wu ◽  
Shoushuang Huang ◽  
Dayong Chen ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Graphene Nanosheets ◽  
High Surface ◽  
High Surface Area ◽  
Microstructural Characteristics ◽  
Facile Hydrothermal Method ◽  
Potential Applications ◽  
Visible Light Photocatalytic

Heterostructures formed by the growth of one kind of nanomaterial in/on another have attracted increasing attention due to their microstructural characteristics and potential applications. In this work, SnS2–SnO2 heterostructures were successfully prepared by a facile hydrothermal method. Due to the enhanced visible-light absorption and efficient separation of photo-generated holes and electrons, the SnS2–SnO2 heterostructures display excellent photocatalytic performance for the degradation of rhodamine (RhB) under visible-light irradiation. Additionally, it is found that the introduction of graphene into the heterostructures further improved photocatalytic activity and stability. In particular, the optimized SnS2–SnO2/graphene photocatalyst can degrade 97.1% of RhB within 60 min, which is about 1.38 times greater than that of SnS2–SnO2 heterostructures. This enhanced photocatalytic activity could be attributed to the high surface area and the excellent electron accepting and transporting properties of graphene, which served as an acceptor of the generated electrons to suppress charge recombination. These results provide a new insight for the design and development of hybrid photocatalysts.

Cr Doped TiO2 Supported on TUD-1 Photocatalyst for Dye Photodegradation

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Ooi Yee Khai ◽  
Leny Yuliati ◽  
Siew Ling Lee
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Xrd Analysis ◽  
Bandgap Energy ◽  
Doped Tio2 ◽  
Visible Light Driven ◽  
Synthesized Materials

New visible light driven photocatalysts of 1 mol% Cr doped TiO2 supported on TUD-1 have been successfully synthesized. The Cr-TiO2/xTUD-1 (x = 10, 20, 30, 40 and 50) photocatalysts were prepared via surfactant-free sol-gel method followed by wet impregnation procedures. XRD analysis revealed that both TiO2 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis showed the existence of Si-O-Ti in all the materials. As observed, tetrahedral-coordinated Ti species were dominant in Cr-TiO2/10TUD-1, Cr-TiO2/20TUD-1 and Cr-TiO2/30TUD-1. Meanwhile, octahedral- coordinated Ti species were the dominant species in Cr-TiO2/40TUD-1 and Cr-TiO2/50TUD-1. It has been demonstrated that the amount of TUD-1 as photocatalyst support affected the wavelength response and the bandgap energy of the resulting materials. All the materials have bandgap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was tested out in dye photodegradation under visible light irradiation at 298 K for 5 hours. Results showed that all Cr-TiO2/TUD-1 materials had higher photocatalytic activity than that of Cr-TiO2. This could be explained by the high surface area and porosity provided by TUD-1 in enhancing the adsorption and diffusivities of the dye molecules, hence leading to the promising photocatalytic activity. Among the materials prepared, Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradation.

High surface area TiO2 nanoparticles: impact of carboxylporphyrin sensitizers in the photocatalytic activity

2020 ◽  
Vol 21 ◽  
pp. 100774
Author(s):  
Caique Prado Machado de Oliveira ◽  
Ana Luísa Almeida Lage ◽  
Dayse Carvalho da Silva Martins ◽  
Nelcy Della Santina Mohallem ◽  
Marcelo Machado Viana
Keyword(s):  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area

scholarly journals High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis

2016 ◽  
Vol 7 ◽  
pp. 1338-1349 ◽  
Author(s):  
Bilel Chouchene ◽  
Tahar Ben Chaabane ◽  
Lavinia Balan ◽  
Emilien Girot ◽  
Kevin Mozet ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Average Length ◽  
High Surface ◽  
Zno Nanorods ◽  
High Surface Area ◽  
Visible Region ◽  
Solar Light ◽  
Effective Electron ◽  
Doped Zno ◽  
Zno Rods

Ce-doped ZnO (ZnO:Ce) nanorods have been prepared through a solvothermal method and the effects of Ce-doping on the structural, optical and electronic properties of ZnO rods were studied. ZnO:Ce rods were characterized by XRD, SEM, TEM, XPS, BET, DRS and Raman spectroscopy. 5% Ce-doped ZnO rods with an average length of 130 nm and a diameter of 23 nm exhibit the highest photocatalytic activity for the degradation of the Orange II dye under solar light irradiation. The high photocatalytic activity is ascribed to the substantially enhanced light absorption in the visible region, to the high surface area of ZnO:Ce rods and to the effective electron–hole pair separation originating from Ce doping. The influence of various experimental parameters like the pH, the presence of salts and of organic compounds was investigated and no marked detrimental effect on the photocatalytic activity was observed. Finally, recyclability experiments demonstrate that ZnO:Ce rods are a stable solar-light photocatalyst.

Preparation of Mesoporous TiO2 Microspheres by Ultrasonic-Hydrothermal Process and its Photocatalysis

2012 ◽  
Vol 578 ◽  
pp. 99-104
Author(s):  
Yang Lin Liu ◽  
Xue Chen Duan ◽  
Shu Yun Liu ◽  
Yan Yan Liu
Keyword(s):  
Photocatalytic Activity ◽  
Crystal Size ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Heat Treating ◽  
Mesoporous Tio2 ◽  
Average Crystal Size ◽  
Tio2 Microspheres ◽  
Effects Of Temperature

Mesoporous TiO2 microspheres were prepared by Ultrasonic-Hydrothermal Process with tetrabutyltitanate as titanium resource and octadecylamine as template. The effects of temperature and time of hytrothermol process, and calcination temperature on the structure had been investigated via XRD,SEM,TEM.The results indicated it will be better hythrothermol treating 20h at 120°Cand then heat-treating 4h at 400°C. A high surface area of 261.7 m2/g and pore volume of 0.28cm3/g was obtained in the corresponding sample with quite narrow distribution,and centering at 4.3nm in diameter.TiO2 frame was highly crystallized, showed the characteristic of pure anataste, with average crystal size of 10.0nm. The as-prepared sample possess a morphology of microspheres with diameter about 100-300nm.The photocatalytic activity was valuated by photodegradation of methly orange. The resultes indicated 99.79% of methly orange in the solution was removed after 30min photocatalytic treatment.

scholarly journals Anodization growth of self-organized ZrO2 nanotubes on zircaloy-4. Evaluation of the photocatalytic activity

2015 ◽  
Vol 20 (3) ◽  
pp. 627-635
Author(s):  
Patricia María Perillo ◽  
Daniel Fabián Rodríguez
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Ammonium Fluoride ◽  
Ion Concentration ◽  
Light Illumination ◽  
Self Organized ◽  
Halogen Light ◽  
Zro2 Nanotubes ◽  
Crystal Type ◽  
Main Factor

ABSTRACTZrO2nanotube arrays were prepared through anodic oxidation in glycerol organic electrolyte containing ammonium fluoride. The morphology of these nanotube arrays can be controlled by changing the preparation parameters such as applied voltage, fluoride ion concentration and time of anodization. While the oxidation voltage is the main factor that controls the diameter of nanotubes, the length of nanotubes is mainly depending on the oxidation time, and the crystal type is closely related to the annealing temperature. We also studied their photocatalytic performance. The photocatalytic activity of samples was calculated by the degradation of a model dye, under halogen light illumination.

scholarly journals In-Situ Synthesis of Nb2O5/g-C3N4 Heterostructures as Highly Efficient Photocatalysts for Molecular H2 Evolution under Solar Illumination

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 169 ◽  
Author(s):  
Faryal Idrees ◽  
Ralf Dillert ◽  
Detlef Bahnemann ◽  
Faheem Butt ◽  
Muhammad Tahir
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Photogenerated Electron ◽  
Band Alignment ◽  
Solar Irradiation ◽  
Electron Hole ◽  
The Impact

This work focuses on the synthesis of heterostructures with compatible band positions and a favourable surface area for the efficient photocatalytic production of molecular hydrogen (H2). In particular, 3-dimensional Nb2O5/g-C3N4 heterostructures with suitable band positions and high surface area have been synthesized employing a hydrothermal method. The combination of a Nb2O5 with a low charge carrier recombination rate and a g-C3N4 exhibiting high visible light absorption resulted in remarkable photocatalytic activity under simulated solar irradiation in the presence of various hole scavengers (triethanolamine (TEOA) and methanol). The following aspects of the novel material have been studied systematically: the influence of different molar ratios of Nb2O5 to g-C3N4 on the heterostructure properties, the role of the employed hole scavengers, and the impact of the co-catalyst and the charge carrier densities affecting the band alignment. The separation/transfer efficiency of the photogenerated electron-hole pairs is found to increase significantly as compared to that of pure Nb2O5 and g-C3N4, respectively, with the highest molecular H2 production of 110 mmol/g·h being obtained for 10 wt % of g-C3N4 over Nb2O5 as compared with that of g-C3N4 (33.46 mmol/g·h) and Nb2O5 (41.20 mmol/g·h). This enhanced photocatalytic activity is attributed to a sufficient interfacial interaction thus favouring the fast photogeneration of electron-hole pairs at the Nb2O5/g-C3N4 interface through a direct Z-scheme.

Photocatalytic activity of Perovskites for degradation of dyes

2021 ◽  
Vol 25 (9) ◽  
pp. 146-150
Author(s):  
A.B. Bhavyasree ◽  
K.P. Latha ◽  
H.S. Jayanna
Keyword(s):  
Thermal Stability ◽  
Photocatalytic Activity ◽  
Magnetic Property ◽  
Metal Oxides ◽  
High Surface ◽  
High Surface Area ◽  
Research Field ◽  
Mixed Metal Oxides ◽  
Degradation Of Dyes ◽  
Broad Overview

Perovskites are mixed metal-oxides which have received much attention and more applicative interests in the research field as well as in industry due to their unique properties like high surface area, small size, excellent magnetic property, thermal stability and low price. Perovskites are effectively used as semiconductors, adsorbents, catalyst, Superconductors etc. The present study outlined the broad overview of the Perovskite as photocatalyst.

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