US Government As Represented by the Secretary of the Army

Vijay S Parameshwaran

Paul H Shen

Michael Wraback

Anand Venktesh Sampath

Disclosed is a semiconductor-liquid junction based photoelectrochemical (PEC) cell for the unassisted solar splitting of water into hydrogen and oxygen gas, the solar-driven reduction of COto higher-order hydrocarbons, and the solar-driven synthesis of NH. The disclosed system can employ a photocathode based upon wurtzite hexagonal semiconductors that can be tailored with proper band alignment for the redox potentials for water, COreduction, and NHproduction, and with bandgap energy for maximum solar absorption. The design maximizes the carrier collection efficiency by leveraging spontaneous and piezoelectric polarization in these materials systems to generate hot electrons within the photocathode. These electrons have sufficient excess energy, preserved at a designed energy capture region, to overcome the kinetic overpotential (surface chemistry limitation) required for the reactions to occur at a high rate.

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Greenbelt, MD, United States of America

Vijay S Parameshwaran