Water Soluble Constituents Responsible for the Browning of Green Tea Infusion

Tanaka, Shizuo

doi:10.5979/cha.1982.80

Cited by 2 publications

(2 citation statements)

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“…The experimental conditions are listed in Table I. The equipment used consisted of a gaseous HCHO generating system, a reactor for HCHO decomposition, and associated instruments to measure the rate of decrease in HCHO concentration [21,22]. The relative humidity of the airflow was adjusted by controlling the flow rates of dry air and humid air.…”

Section: Methodsmentioning

confidence: 99%

Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Nakano

Kogoshi

Katayama

2015

e-J. Surf. Sci. Nanotech.

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TiO2 photocatalysts can remove harmful substances such as volatile organic compounds (VOCs) under light irradiation. However, they are only activated by ultraviolet light at wavelengths shorter than about 380 nm, so they cannot be used under visible light irradiation. Thus, visible-light-responsive photocatalysts have been studied extensively to enable their indoor use. TiO2 powder supported with Cu(II) ions (Cu(II)/TiO2) has recently been reported to possess visible-light photocatalytic activity. In the present study, we used cupric acetate as a Cu(II) source. We prepared various Cu(II)/TiO2 photocatalysts by changing the amount of cupric acetate and assessed their photocatalytic performance. The performance of Cu(II)/TiO2 photocatalysts was estimated from the rate of decrease in the formaldehyde (HCHO) concentration in the flowing stimulant air under irradiation by a fluorescent lamp or a white LED. The surface properties of Cu(II)/TiO2 photocatalysts were analyzed by X-ray photoelectron spectroscopy (XPS) measurements. The optical reflectance of Cu(II)/TiO2 photocatalysts was measured by using a UV-Vis spectrophotometer. The maximum visible-light photocatalytic activity was observed at a Cu/TiO2 weight ratio of 5.69 [wt%]. The maximum rate of decrease in the HCHO concentration of the Cu(II)/TiO2 photocatalyst was higher than twice that of a typical commercial TiO2-based visible-light-responsive photocatalyst (IshiharaSangyo MPT-623) under the same test conditions.

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Section: Methodsmentioning

confidence: 99%

Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Nakano

Kogoshi

Katayama

2015

e-J. Surf. Sci. Nanotech.

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“…The device consisted of a gaseous HCHO generating system, a reactor for HCHO decomposition, and associated instruments to measure the rate of decrease in HCHO concentration. 16,17) The relative humidity of the air stream was adjusted by controlling the flow rates of dry air and wet air and the HCHO concentration in the air flow was adjusted by varying the amount of dry air passing through a vessel containing HCHO solution consisting of paraformaldehyde without methanol. The major oxidative and reductive processes involved in the photodegradation of HCHO are represented by reactions (1) to (4), given below, in which reactions (2) and (3) represent the oxidation and reaction (4) represents the reduction.…”

Section: Methodsmentioning

confidence: 99%

Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO₂prepared with Ar/H₂plasma surface treatment

Nakano¹,

Yazawa²,

Araki³

et al. 2014

Jpn. J. Appl. Phys.

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Oxygen-deficient TiO 2 (TiO 2%x ) has been proposed as a visible-light-responsive photocatalyst. TiO 2%x thin films were prepared by Ar/H 2 plasma surface treatment, applying varying levels of microwave input power and processing times. The highest visible light photocatalytic activity was observed when using an input power of 200 W, a plasma processing time of 10 min, and a 1 : 1 Ar : H 2 ratio, conditions that generate an electron temperature of 5.7(+1.0) eV and an electron density of 8.5 ' 10 10 cm %3 . The maximum formaldehyde (HCHO) removal rate of the TiO 2%x film was 2.6 times higher than that obtained from a TiO 2%x N x film under the same test conditions.

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Water Soluble Constituents Responsible for the Browning of Green Tea Infusion

Cited by 2 publications

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Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO₂prepared with Ar/H₂plasma surface treatment

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Water Soluble Constituents Responsible for the Browning of Green Tea Infusion

Cited by 2 publications

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Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Cu-Supported TiO<sub>2 </sub>with High Visible-Light Photocatalytic Activity Prepared Using Cupric Acetate

Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO2prepared with Ar/H2plasma surface treatment

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Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO₂prepared with Ar/H₂plasma surface treatment