Solar photoelectrocatalytic

Benniston AC, Haniman A (2008) Artificial photosynthesis. Materials Today 11 26-34 Inoue T, Fujishima A, Konishi S, Honda K (1979) Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders. Nature 277 637-638 Halmann M (1978) Photoelectrochemical reduction of aqueous carbon dioxide on p-type gallium phosphide in liquid junction solar cells. Nature 275 115-116 Heminger JC, Carr R, Somorjai GA (1987) The photoassisted reaction of gaseous water and carbon dioxide adsorbed on the SrH03 (111) crystal face to form methane. Chem Phys Lett 57 100-104... 

The large-scale spread of DAFCs is closely related to the development of efficient anodic and cathodic materials, characterized by very fast electrochemical kinetics, stability at the high current densities in alkaline environments and modest cost. This objective requires cathodes without noble metals and anodes with very low amounts of noble metals. In order to improve the cheapness and sustainability of the processes described above, the most accepted opinion is the possibility of using solar light by means of the introduction of Ti02, pure or doped, into the electrode material formulation. Figure 4.15 shows a typical laboratory-scale photoelectrocatalytic reactor. 

Ampelli C., Centi, G., Passalacqua, R., and Perathoner, S. (2010) Synthesis of solar fuels by a novel photoelectrocatalytic approach. Energy t. Environmental Science, 3 (3), 292-301. 

Photoelectrochemical Decomposition of HaS. The photo-electrochemical decomposition ofHjS on CdSe with solar light alone has an efficiency of only 1.8% (Kainthla, 1987). However, photoelectrocatalytic processes and the use of two-electrode photocells would be expected to greatly increase the efficiency of conversion.29... 

As interfacial properties control charge transfer, surface recombination, and stabihty, their optimization is a key to effldent and stable operation in solar energy-converting structures and devices. The examples considered here are related to the development of either photovoltaic or photoelectrocatalytic efficient systems that wiU be described in Sections 2.5 and 2.6. The case studies begin with the more detailed continuation of the above described formation of nanotopographies on Si... 

The in situ interface conditioning of p-lnP by photoelectrochemical processes, described in Section 2.4.2, is a key procedure for the preparation of efficient and stable photovoltaic and photoelectrocatalytic solar cells and surface analyses wiU be presented that describe the induced chemical and electronic changes. The ternary chalcopyrites CulnSe2 and CulnS2 have meanwhile been developed for use in commercially available solid-state solar cells. For the sulfide-based cell, the use of a toxic KCN etch step of Cu-rich CulnS2 to remove Cu-S surface phases is considered as deleterious for wide-scale application and an electrochemical method will be presented in Section 2.4.3 that replaces the chemical etching procedure. 

Indium phosphide has been a successful material in the preparation of solid-state, photovoltaic, and photoelectrocatalytic electrochemical solar cells [237-240]. Photovoltaic soUd-state solar cells reach single-junction efHciencies above 24% [237]. When used as a photocathode in photoelectrochemical solar energy conversion, the material has shown excellent stability [239], related to the unique surface chemistry of the polar InP(lll) A-face that exposes In atoms only [240]. The photoelectrochemical conditioning of single-crystalline p-type InP with the aim of preparing efficient and stable photoelectrochemical solar cells for photovoltaic and photoelectrocatalytic operation is described in the following and the induced surface transformations are analyzed employing a variety of surface-sensitive methods. 

Finally, photoelectrocatalytic (PEC) technologies based on the use of a photoactive anode illuminated with UVA or solar light have also been recently developed for the destmction of pollutants [1], In classical Ti02 photocatalysis, which has been the most explored variant, these energy sources promote one electron from the valence to the conduction band (e cs) producing a hole (h ) by reaction (14). The adsorbed organic matter can then be directly oxidized under the action of h", by reaction (15), or OH produced by reaction (16) ... 

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