Solar-powered hydrogen production via water splitting with simultaneous water treatment

ENVR 188

Hyunwoong Park, hpark@caltech.edu, Chad D. Vecitis, vecitis@its.caltech.edu, and Michael R. Hoffmann, mrh@caltech.edu. Environmental Science and Engineering, California Institute of Technology, W. M. Keck Laboratories 138-78, 1200 E. California Blvd., Pasadena, CA 91125
Hydrogen, as a renewable energy source, is proving to be an attractive alternative due to high cost of fossil fuel-based energy and a growing demand for environmentally clean energy sources and lower carbon footprints. We have developed a hybrid photovoltaic electrochemical device for the simultaneous treatment of aqueous chemical pollutants at metal (e.g., Nb, Bi)-doped TiO2 anodes coupled with the production of molecular hydrogen via water splitting at stainless steel cathodes. The anodic oxidation of aqueous chemical contaminants in water has a synergistic effect on hydrogen production that results in a 30 to 60% increase in H2 production efficiency. Overall energy efficiencies are comparable to those of conventional electrolysis. Conventional water and wastewater treatments are energy-intensive and energy-inefficient processes. Accordingly, this PV-hybrid system could be applied directly for water and wastewater treatment where hydrogen fuel is produced as an useful, energy-rich by-product.