Direct water splitting

Bare CuOx-supported nanostructures showed some activity in H 2 production from methanol-water mixture under UV-visible irradiation [180]. Ni is also used as a dopant, and small amounts (1 wt.%) of this element in mesoporous titania guarantee good activity in water-methanol mixtures under UV-visible light [181]. Indium-tantalum oxide Ni-doped materials also provided photocatalysts with promising efficiencies for direct water splitting [182]. TiOz nanotubes doped with Ir and Co nanopartides were effective for visible light water splitting even in the absence of... 

Non-oxide Suspended Particle Systems and Direct Water Splitting 455... 

S 17.3 million Renewables - direct water splitting using solar energy thermal processes using biomass advanced electrolysis from wind power. 

Direct water splitting chemical cycles (Sulfur Iodine)... 

It was concluded that by combining a hematite nanorod electrode with a suitable water oxidation catalysts, for instance platinum or ruthenium dioxide, the photoelectrochemical activity for direct water splitting applications should increase by a factor of 20. 

S. Ihara, Feasibility of hydrogen production by direct water splitting at high temperature, Int. J. Hydrogen Energy, 3 287-296 (1978). 

Each step requires less energy than that needed for direct water splitting as follows ... 

Required energies and entropy changes of reaction for HHLT are shown in Table 1. In HHLT, total required electrical energy is 113.4 kJ/mol for 1 mol H2 production and it is about half of direct water splitting (204.9 kJ/mol at 500°C, [5]). 

In equation (4), n is number of electron (= 2 for 1 oxygen atom) and F is Faraday constant. Theoretical voltage of sulfLiric acid synthesis reaction (equation (1)) is 0.17V-0.29V, therefore, total theoretical voltage in EIHLT is expected to be lower than 0.5V which is about half of the theoretical voltage of direct water splitting (Eg h2o), about IV. 

As part of the search for alternatives to fossil fuel, recent studies have focused on the production of hydrogen, a clean and renewable energy carrier, by direct water splitting... 

Work on the stability and efficiency characteristics of amorphous silicon structures for direct water splitting systems clearly showed that it is feasible to utilize amorphous silicon devices in direct contact with aqueous electrolytes without additional protective coatings. 

General Motors Corporation, entitled "Renewable Energy, Hydrogen, and Direct Water-Splitting Systems", September 17, 2001. 

Chemistry Department of the Colorado School of Mines entitled "Photoelectrochemical Direct Water Splitting Systems", October 4, 2001. 

North Carolina State University entitled "Photoelectrochemical Systems for Hydrogen Production via Direct Water Splitting", October 30, 2001. 

In another approach, semiconductor materials and devices which are stable in aqueous environment are taken to apply sunlight for direct water splitting. The conversion efficiency, however, is still insignificant, since only a very small portion of the solar spectrum is used. Photolytic response, however, could be shifted into the visible region using chomophores called sensitizers [73]. Research is focusing on the development of transparent and highly active catalysts and techniques of surface modification to increase lifetime and efficiency of PEC devices. 

H.L. Wang, T. Deutsch, J.A. Turner, Direct water splitting under visible light with nanostructured hematite and WO3 photoanodes and a GaInP2 photocathode. J. Electrochem. Soc. 155, F91-F96 (2008)... 

Arakawa, H., Zou, Z., Sayama, K., Abe, R. Direct water splitting by new oxide semiconductor photocatalysts under visible light irradiation. Pure Appl. Chem. 79, 1917-1927 (2007)... 

Naito, H. and Arashi, H. (1995) Hydrogen production from direct water splitting at... 

Recently, it has also been found that carbon nanodots exhibit unique catalytic properties when coupled with carbon nitride for pure water splitting [6]. It has been found that the presence of C nanodots facilitates the formation and decomposition of H2O2 (2e process) whilst inhibiting direct water splitting (4e process), thus resulting in a magnificent QE of 16 % under 420 nm irradiation condition and 2 %... 

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