Low Temperature Preparation and Optical Hydrogen Response of Pd/Titania Composite Film

2011 ◽  
Vol 485 ◽  
pp. 275-278 ◽  
Author(s):  
Junichi Hamagami ◽  
Ryo Araki ◽  
Shohei Onimaru ◽  
Hiroyuki Oda ◽  
G. Kawamura ◽  
...  

Photocatalytic titania coatings loaded with palladium catalyst were prepared onto soda-lime glass substrates by using a low temperature synthesis for application of optical hydrogen gas sensor. Titania coatings were formed on the glass substrate by a sol-gel spin-coating process followed by a hot water treatment at 55°C. Metallic palladium nanoparticles were deposited onto the titania coatings, which obtained with addition of poly(ethylene glycol) (PEG) and without PEG after the hot water treatment, by means of a photodeposition technique at room temperature using UV-light irradiation. The whole fabrication process was carried out under atmospheric pressure. The Pd-photodeposited titania coating obtained with addition of PEG after hot water treatment showed higher hydrogen sensing properties than that obtained without PEG.

2013 ◽  
Vol 566 ◽  
pp. 249-252 ◽  
Author(s):  
Junichi Hamagami ◽  
Shohei Onimaru ◽  
Ryo Araki ◽  
G. Kawamura ◽  
Atsunori Matsuda

Transparent titania coating was formed onto a flexible polycarbonate plastic substrate by low-temperature fabrication process below 100 °C consisting of a sol-gel technique and a hot water treatment method. The titania coating with high transparency showed a good photocatalytic activity under ultraviolet (UV) light irradiation. Palladium metal acts as a catalyst for dissociative adsorption of hydrogen gas at room temperature under an atmospheric pressure. The palladium catalyst was deposited on the photocatalytic titania coating by a photodeposition process at room temperature under UV-light irradiation. The flexible polycarbonate plastic sheet with semitransparent palladium-deposited titania coating works as an optically readable hydrogen gas sensor which can operate at room temperature.


MRS Advances ◽  
2020 ◽  
pp. 1-9
Author(s):  
Ranjitha Kumarapuram Hariharalakshmanan ◽  
Nawzat S. Saadi ◽  
Busra Ergul-Yilmaz ◽  
Khalidah H. Al – Mayalee ◽  
Tansel Karabacak

Abstract The use of zinc oxide (ZnO) nanostructures as a photocatalyst for the degradation of organic pollutants in water has received significant attention over the recent years. However, synthesis methods for producing ZnO nanostructures are generally costly, complicated, and hazardous to the environment. In this work, we demonstrate the synthesis of ZnO nanostructures by a simple hot water treatment (HWT) method and the photocatalytic activity of the hence produced nanostructures. HWT is a one-step, low-cost, eco-friendly, and scalable nanostructure growth method. By HWT, various metal-oxide nanostructures can be produced simply by the interaction of metals with hot water without the need for any chemical additives in the solution. Growth of metal-oxide nanostructures by HWT involves the formation of metal-oxides and their release from the surface of the metal into water, the migration of the metal-oxides in water, and their re-deposition at a different part of the metallic surface, which initiates the growth of nanostructures. In this study, we used zinc powder and plates for producing the ZnO nanostructures by HWT in DI water at 75°C. Scanning electron microscopy and X-ray diffraction were utilized to verify the formation of ZnO nanostructures. Zinc plates produced a suspension of ZnO nanostructures in water, while on the other hand, zinc powder resulted in ZnO nanostructures grown on the powder surface as well as standalone ZnO nanostructures also mixed in water. We used these nanostructures + water suspensions for our photocatalytic degradation studies. Methylene blue (MB) was used as a model organic pollutant. We mixed the ZnO nanostructure suspension with MB and exposed it to UV light. The degradation of MB was observed by measuring its absorbance values using a UV-Visible spectrophotometer over a period of 4 hours. We observed a 20% decrease in the concentration of MB in 4 hours when nanostructured Zn/ZnO powder suspension was used, and a 30% decrease was achieved when ZnO nanostructure-only suspension produced from zinc plates was used. MB alone was also exposed to UV light for the same period as a control experiment, and we did not observe any significant decrease in its concentration. These results indicate that the hot water treatment method presents a very simple, cost-effective, scalable, and eco–friendly alternative for the synthesis of ZnO nanostructures for photocatalytic water treatment applications.


2008 ◽  
Vol 516 (14) ◽  
pp. 4526-4529 ◽  
Author(s):  
Kiyoharu Tadanaga ◽  
Naoko Yamaguchi ◽  
Yusuke Uraoka ◽  
Atsunori Matsuda ◽  
Tsutomu Minami ◽  
...  

2006 ◽  
Vol 41 (24) ◽  
pp. 8101-8108 ◽  
Author(s):  
Atsunori Matsuda ◽  
Yugo Higashi ◽  
Kiyoharu Tadanaga ◽  
Masahiro Tatsumisago

2005 ◽  
Vol 88 (6) ◽  
pp. 1421-1426 ◽  
Author(s):  
Atsunori Matsuda ◽  
Tatsuo Matoda ◽  
Kiyoharu Tadanaga ◽  
Tsutomu Minami ◽  
Masahiro Tatsumisago ◽  
...  

2010 ◽  
Vol 445 ◽  
pp. 100-104 ◽  
Author(s):  
Junichi Hamagami ◽  
Ryo Araki ◽  
Hiroyuki Oda ◽  
Mototsugu Sakai ◽  
Atsunori Matsuda

Palladium (Pd) nanoparticles were prepared on photocatalytic TiO2-coated glass substrate by a photodeposition process and the optical hydrogen sensing properties were examined at room temperature. The TiO2 coatings were prepared on a non-alkaline glass substrate by a sol-gel process and hot water treatment. Pd nanoparticles were deposited on the TiO2 film by photodeposition using UV light. The obtained Pd/TiO2 thin film showed remarkable optical transmittance response to hydrogen gas at room temperature. The normalized transmittance of the Pd/TiO2 thin film at a wavelength of 640 nm decreased to 0.9 on exposing the film to hydrogen gas for only 5 s. This transmittance decrease is considered to be due to a gaschromic effect of the TiO2 photocatalytic coating.


2015 ◽  
Vol 1125 ◽  
pp. 106-110 ◽  
Author(s):  
Ili Liyana Khairunnisa Kamardin ◽  
Ainun Rahmahwati Ainuddin

Zinc Oxide (ZnO) known as wide band gap semiconductor with large excitation energy 60 meV, noncentral symmetry, piezoelectric and biocompatible for biomedical application are the unique characteristic that attract many researcher’s attention on ZnO nanostructure synthesis and physical properties. ZnO thin films were deposited on Si Glass substrate by a sol-gel process. The starting solution were prepare by dissolved zinc acetate dehydrate (ZnAc) and diethanolamine (DEA) in water (H2O) and 2-propanol (2-PrOH). 0 to 60 drops of NaOH were dropped into 100 ml sol-gel solution to study effect of sol-gel modification. ZnO thin films were obtained after preheating the spin coated thin films at 100 °C for 10 minutes after each coating. The coated substrates were undergone for Hot Water Treatment (HWT) process at 90 °C for 6 hours to grow ZnO nanostructures. The effects of sol-gel modification by drop of NaOH into the solution were studied. ZnO nanorods and nanoflakes were obtained after hot water treated at 90 °C for 6 hours with different amount of NaOH dropped directly in the sol-gel solution. On the basis of the changes in morphology and microstructure induced by hot water treatment, it is concluded that the amount of NaOH dropped into sol-gel effected morphology of ZnO growth.


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