Hydrogen from photovoltaic cells

Power for industrial operations is supplied at present by electricity from coal, natural gas, and oil, working heat engines at overall efficiencies of < 35%. All can be replaced by fuel cells of various kinds operating for the next two to three decades on hydrogen from re-formed fossil fuels and as soon as possible by hydrogen from photovoltaics and the decomposition of water.20... 

Tien HT, Chen JW (1989) Hydrogen generation from artificial sea water in a semiconductor septum electrochemical photovoltaic cell. Photochem Photobiol 49 527-530... 

Tien HT, Chen JW (1990) Hydrogen production from water by semiconductor septum electrochemical photovoltaic cell using visible light. Int J Hydrogen Energy 15 563-568... 

PHOTOVOLTAIC CELLS CAN BE USED TO PRODUCE HYDROGEN FROM WATER... 

Historically, and in space, alkaline fuel cells are run on pure H2 and 02. There is as yet no massive terrestrial source of hydrogen (e.g., from photovoltaics and the... 

The brute force approach to achieve this goal is to employ a solid-state photovoltaic cell to generate electricity that is subsequently passed into a commercial-type water electrolyzer. Although efficiencies obtained are relatively high, i.e., close to 8 %, these devices are very expensive. Hence the price of hydrogen produced this way cannot compete with conventional sources. The long-term outlook is better for systems that borrow their principles from natural photosynthesis (see Section 1.4.1 above). 

Ottova et al. looked at two-compartment semiconductor-septum electrochemical photovoltaic cells with cadmium selenide and cadmium selenide telluride for water photolysis [126], They used cells consisting of two chambers separated by a CdSe or CdSe/CdTe bipolar electrode. The bipolar electrodes were prepared by painting a CdSe slurry on a metal substrate or by ultrasound-aided electrodeposition from CdSe solution in ZnCl2. The photoresponse (voltage and current output) and hydrogen yield from photo-induced electrolysis of H20 in the dark chamber of the cell were evaluated as a function of CdSe preparation method. The ultrasound-aided deposition technique gave excellent coatings of CdSe. 

This is not only due to the higher efficiency of battery powered vehicles, but also to the lower efficiency of the overall process necessaiy to assure hydrogen feeding to fuel cells, i.e., production of electricity stalling from the primary resource plus hydrogen production by electrolysis (13% from nuclear and 5% from photovoltaic, to be compared with values corresponding to electricity production... 

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