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Journal ArticleDOI

Heterogeneous photocatalytic production of hydrogen and methane from ethanol and water

01 Jun 1981-Chemical Physics Letters (North-Holland)-Vol. 80, Iss: 2, pp 341-344
TL;DR: The quantum yield of hydrogen production was increased greatly by supporting metals or metal complexes on the TiO2 surface, amounting to 38% for a Pt-TiO2 photocatalyst.
About: This article is published in Chemical Physics Letters.The article was published on 1981-06-01. It has received 218 citations till now. The article focuses on the topics: Hydrogen production & Hydrogen.
Citations
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Journal ArticleDOI
TL;DR: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,†
Abstract: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

1,990 citations

Journal ArticleDOI
TL;DR: In this paper, the authors measured the rate of decrease in the integrated IR absorbance associated with the C-H stretching vibrations of a thin solution-cast film of stearic acid under 365 nm or 254 nm (0.8 mW/cm2) irradiation.
Abstract: In the context of studying the feasibility of photocatalytically self-cleaning windows and windshields, clear, abrasion resistant, photocatalytic films of TiO2 were formed on soda lime glass and on fused quartz by a sol-gel process. The rate of photooxidation of contaminant deposits was estimated by measuring the rate of decrease in the integrated IR absorbance associated with the C-H stretching vibrations of a thin solution-cast film of stearic acid under 365 nm (2.4 mW/cm2) or 254 nm (0.8 mW/cm2) irradiation. Approximately 3 × 10−4 stearic acid molecules were stripped per 365 nm photon in either front- or back-illuminated soda lime glass, and 6 × 10−4 molecules when the films were coated on fused quartz. For thin TiO2 films on fused quartz, the rate of photooxidation, normalized by the number of photons absorbed per unit area, was independent of the wavelength. In contrast, for films on soda lime glass, the rate of photooxidation, when similarly normalized, was higher for the less penetrating wavelength. The reduced photoactivity on glass at the deeply penetrating wavelength (365 nm), as well as the greater photoefficiency on quartz than on glass, are attributed to diffusion of sodium oxide from the glass into the inner glass-contacting zone of the TiO2 layer.

512 citations

Book ChapterDOI
TL;DR: In this article, small particles of metals in solution often behave like electrodes although they are not connected to a battery which determines their potential, and when a chemical reaction occurs in the solution of such particles intermediate free radicals may transfer electrons to them.
Abstract: Small particles of metals in solution often behave like electrodes although they are not connected to a battery which determines their potential. However, when a chemical reaction occurs in the solution of such particles intermediate free radicals may transfer electrons to them. The particles are thus charged chemically and are able to act as a metal electrode on cathodic potential. Electron transfer reactions become possible at these micro-electrodes which cannot be brought about by the radicals in the absence of the colloidal catalyst.

453 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of Ni(OH)2 cluster loading content on the photocatalytic hydrogen production rates of the as-prepared samples in methanol aqueous solution was investigated.
Abstract: Ni(OH)2 cluster-modified TiO2 (Ni(OH)2/TiO2) nanocomposite photocatalysts were fabricated by a simple precipitation method using Degussa P25 TiO2 powder (P25) as support and Ni(NO3)2 as precursor. The effect of Ni(OH)2 cluster loading content on the photocatalytic hydrogen production rates of the as-prepared samples in methanol aqueous solution was investigated. The results showed that the photocatalytic H2-production activity of TiO2 was significantly enhanced by loading Ni(OH)2 clusters. The optimal Ni(OH)2 loading content was found to be 0.23 mol %, giving a H2-production rate of 3056 μmol h−1 g−1 with quantum efficiency (QE) of 12.4%, exceeding that on pure TiO2 by more than 223 times. This high photocatalytic H2-production activity is due to the deposition of Ni(OH)2 clusters on the surface of TiO2. The enhanced mechanism is because the potential of Ni2+/Ni (Ni2+ + 2e− = Ni, Eo = −0.23 V) is slightly lower than conduction band (CB) (−0.26 V) of anatase TiO2, meanwhile higher than the reduction potent...

389 citations

References
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Journal ArticleDOI
07 Jul 1972-Nature
TL;DR: Water photolysis is investigated by exploiting the fact that water is transparent to visible light and cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm.
Abstract: ALTHOUGH the possibility of water photolysis has been investigated by many workers, a useful method has only now been developed. Because water is transparent to visible light it cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm (ref. 1).

27,819 citations

Journal ArticleDOI
31 Jul 1980-Nature
TL;DR: In this paper, the authors showed that the irradiation of the carbohydrates, not only sugar or starch but also cellulose, in the presence of water and a RuO2/TiO 2/Pt photocatalyst powder leads to the efficient production of hydrogen gas.
Abstract: Attempts have been made to find green plants which produce low-molecular weight hydrocarbons1,2 and to find seaweeds which produce hydrogen from water utilizing solar energy3,4. These attempts are aimed at finding methods of making use of the photosynthetic process in plants for direct production. Most green plants, however, synthesize carbohydrates, such as sugar, starch and/or cellulose, from water and carbon dioxide. The C4 plants5, such as corns and sugar cane, grow rapidly, utilizing solar energy with ∼1% efficiency for the fixation of CO2. This value is 10 times larger than that of the average efficiency of photosynthesis of plants, 0.1%. However, the carbohydrates produced by these plants cannot be used directly as fuel. Here we show a new route for the conversion of carbohydrates into hydrogen (a clean fuel in the hydrogen energy system), taking advantage of the photocatalytic process. We found that the irradiation of the carbohydrates, not only sugar or starch but also cellulose, in the presence of water and a RuO2/TiO2/Pt photocatalyst powder leads to the efficient production of hydrogen gas.

552 citations

Journal ArticleDOI
TL;DR: In this article, a spin trap was used to detect free-radical intermediates formed during in situ irradiation of TiO/sub 2/ and platinized polysilicon powders in aqueous solution.
Abstract: Spin trapping and ESR detection (with the traps ..cap alpha..-phenyl N-tert-butyl nitrone and ..cap alpha..-(4-pyridyl N-oxide) N-tert-butyl nitrone) were employed to detect free-radical intermediates formed during in situ irradiation of TiO/sub 2/ and platinized TiO/sub 2/ powders in aqueous solutions. Evidence for the production of hydroxyl radical (.OH) (formed in the oxidation of water) and perhydroxyl radical (HO/sub 2/.) (probably formed in a reduction step) is presented. Other spin adducts, attributed to decomposition reactions of the spin traps, were also found. The results suggest an important role for photogenerated .OH in many photocatalytic and photosynthetic processes at TiO/sub 2/ powders.

533 citations

Journal ArticleDOI
TL;DR: Xe-Lamp irradiation of TiO2 powders mixed with a Pt, Pd, RuO2, or rhodium complex leads to the efficient production of hydrogen from liquid methanol and water at room temperature as mentioned in this paper.
Abstract: Xe-Lamp irradiation of TiO2 powders mixed with a Pt, Pd, RuO2, or rhodium complex, leads to the efficient production of hydrogen from liquid methanol and water at room temperature.

340 citations

Journal ArticleDOI
TL;DR: In this paper, the heterogeneous photocatalytic decomposition of acetic acid on n-type TiO/sub 2/ to yield almost exclusively methane and carbon dioxide is reported.
Abstract: The heterogeneous photocatalytic decomposition of acetic acid on n-type TiO/sub 2/ to yield almost exclusively methane and carbon dioxide is reported. Probable reaction mechanisms are discussed. It is assumed that the TiO/sub 2/ powder acts in a dual function causing the photooxidation of acetate and the reduction of intermediately formed methyl radicals. This property is not found at metal electrodes under usual Kolbe conditions. (JSR)

332 citations