Generating Hydrogen from Sunlight and Water using Photovoltaic Tandem Cell

Abstract:

<p>Realising a sustainable hydrogen economy requires a breakthrough in the production of hydrogen. Photoelectrochemical conversion of solar energy to energy in hydrogen at viable efficiency isa long term goal needed to usher in the Hydrogen economy worldwide. The twin cell technology based Tandem Cell^TM tackles a number of challenges faced by single photoelectrochemical cell based water splitting and offers a novel way of utilising complimentary parts of the solar spectrum in two cells. The overall process results in a complete system driven by solar energy that splits water into hydrogen and oxygen.</p> <p> This program included 12 technical tasks: <ol> <li>Studies on spray nozzle parameters</li> <li>Studies on spray solution parameters</li> <li>Investigation of the mechanised doctor blading technique</li> <li>Investigation of spray pyrolysis techniques</li> <li>Performance of scale-0up electrodes in Tandem Cell^TM</li> <li>Alternative photocatalytic materials</li> <li>Alternative electrolytes</li> <li>A desk study on substrate materials</li> <li>A lab study on substrate materials</li> <li>Alternative design configuration</li> <li>Quality control procedures</li> <li>Fabrication of Tandem Cells</li> </ol></p> <p>The main conclusions resulting from this DTI-assisted project were: <bl> <li>Semiconductor metal oxide spray deposition parameters such as nozzle height and liquid flow rate were optimised in order to improve the photocurrent performance.</li> <li>A number of dopants that improve the performance of photocurrent density over 50% over undoped samples were discovered by a systematic study.</li> <li>A semi-automated method was developed for the production of metal oxide coated electrodes that is suitable for producing larger scale plates, up to 25 x 25 cm². The method would be suitable for further scaling to produce 5m² Tandem Cells/day.</li> <li>A new annealing regime capable of producing crack-free larger scale semiconductor electrodes was introduced.</li> <li>Some new photocatalytic semiconductor materials were highlighted with good potential.</li> <li>An extensive study on alternative electrolytes was conducted and some new electrolyte systems were discovered.</li> <li>A desk and lab study on alternative substrates was conducted.</li> <li>Alternative Tandem Cell design configurations were studied.</li> <li>Quality control procedures were developed for each step of the Tandem Cell production process.</li> <li>An array of 12 Tandem Cells was constructed. This was set up as a demonstration unit in a UK site and produced gas.</li> </bl></p> This report is divided into the following sections: <ol> <li>Introduction</li> <li>Experimental Work</li> <li>Results</li> <li>Discussion</li> <li>Conclusions</li> <li>Recommendations</li> <li>Acknowledgements</li> <li>Figures</li> <li>Appendix</li> </ol>

Author(s):

Hydrogen Solar Ltd