Agenda

Abstract:
Solar energy can be converted to chemical energy stored in hydrogen
through water splitting using a photoelectrochemical device. However,
decades of research have failed to identify one semiconducting
electrode material that can perform the water splitting reaction with
adequate efficiency, stability and material cost. Here I present a
system that overcomes the limitations of conventional materials to
afford direct solar hydrogen production by taking inspiration from
natural photosynthesis and using two photosystems in tandem. In
addition, to reach the terawatt energy scale needed to have a global
impact, I describe the use of abundant and inexpensive semiconducting
materials. Specifically, progress developing hematite (Fe2O3)
photoanodes and cuprous oxide (Cu2O) photocathodes using a two part
strategy of independently controlling the electrode morphology and
surface chemistry will be presented.  I will show that our water
splitting tandem cell, using these materials and inexpensive
processing techniques, is capable of solar-to-hydrogen conversion
efficiencies of over 5 % at standard conditions.