Water splitting efficiency

Previous principal solar water splitting models predict similar dual band gap photoelectrolysis efficiencies of only 16%, and 10-18%, respectively [27, 28]. Each are lower than our observed water splitting efficiency discussed below. The physics of these models were superb, but their analysis was influenced by dated technology and underestimated the experimental ((photo attained by contemporary devices or underestimated the high experimental values of (dectrolysis> which Can be attained. For example, Boltonand coworkers, estimates low values of ((photo (less than 20% conversion) due to assumed cumulative relative... 

Multistep Thermochemical Water Splitting. Multistep thermochemical hydrogen production methods are designed to avoid the problems of one-step water spHtting, ie, the high temperatures needed to achieve appreciable AG reduction, and the low efficiencies of water electrolysis. Although water electrolysis itself is quite efficient, the production of electricity is inefficient (30—40%). This results in an overall efficiency of 24—35% for water electrolysis. 

A detailed discussion of thermochemical water splitting is available (155,165—167). Whereas many problems remain to be solved before commercia1i2ation is considered, this method has the potential of beiag a more efficient, and hence more cost-effective way to produce hydrogen than is water electrolysis. 

In any case, no electrode material or approach fulfills the requirements for a successful photoelectrochemical process in all respects, i.e., for routine practical use hence novel materials and approaches are constantly pursued. Note that beside the robust performance needed, the most important figure of merit for a semiconductor photoelectrode used for water splitting is the photoconversion efficiency, which is... 

Murphy AB, Barnes PRF, Randeniya LK, Plumb 1C, Grey IE, Home MD, Glasscock JA (2006) Efficiency of solar water splitting using semiconductor electrodes. Int J Hydrogen Energy 31 1999-2017... 

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... 

The extension of this approach to artificial leaves based on titanates, niobates, tantalates, metal nitrides and phosphides, metal sulfides, and other transition metal oxides appears possible and useful in order to enhance the photocatalytic efficiency. In addition, the construction of multicomponent systems such as Ti02-CdS or MoS2-CdSe for overall water splitting could also lead to further improvements. This... 

Efficiency of Hydrogen and Oxygen Generation by Water Splitting.244... 

For the operating voltage at the optimum power point Vp and the Faradaic current for water splitting of /p, the overall solar to hydrogen generation PV electrolysis efficiency is given by... 

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