Image courtesy of
Fuding Lin and Shannon Boettcher
To one day design
cells that mimic trees ability to turn sunlight and water into fuel, scientists
at the University
of Oregon devised a new technique that allows them to “see” a key interface
in the cells – the
interface between the semiconductor that absorbs sunlight and generates
electricity with
the catalyst that uses the electricity to create fuel.
(December 5, 2015) With
the help of a new method called "dual-electrode
photoelectrochemistry," University of Oregon scientists have provided new
insight into how solar water-splitting cells work. An important and overlooked
parameter, they report, is the ion-permeability of electrocatalysts used in
water-splitting devices.
Their discovery could help replace a trial-and-error
approach to paring electrocatalysts with semiconductors with an efficient
method for using sunlight to separate hydrogen and oxygen from water to
generate renewable energy, says Shannon W. Boettcher, professor of chemistry
and head of the Solar Materials and Electrochemistry Laboratory in the UO's
Materials Science Institute.
The research is described in a paper placed online Dec. 1 in
advance of regular publication in the journal Nature Materials.
Solar water-splitting cells, which mimic photosynthesis,
require at least two different types of materials: a semiconductor that absorbs
sunlight and generates excited electrons and an electrocatalyst, typically a
very thin film of a metal oxide that contains elements such as nickel, iron and
oxygen, which serves to accelerate the rate at which electrons move on and off
water molecules that are getting split into hydrogen and oxygen.