New Scientist Tech - 2010 March 16
Direct Water Splitting Through Vibrating Piezoelectric Microfibers in WaterEvery drop of water is stuffed with the greenest of fuels, hydrogen, but getting it out is a challenge. A new material raises the prospect of doing so using noise pollution – from major roads, for example.
A team at the University of Wisconsin-Madison made crystals of zinc oxide that, when immersed in water, absorb vibrations and develop areas of strong negative and positive charge. These charges rip apart nearby water molecules, releasing hydrogen and oxygen gas.
- Journal of Physical Chemistry Letters (DOI: 10.1021/jz100027t) March 2, 2010
We propose a mechanism, a piezoelectrochemical effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric ZnO microfibers and BaTiO3 microdendrites. Fibers and dendrites are vibrated with ultrasonic waves leading to a strain-induced electric charge development on their surface. With sufficient electric potential, strained piezoelectric fibers (and dendrites) in water triggered the redox reaction of water to produce hydrogen and oxygen gases. ZnO fibers under ultrasonic vibrations showed a stoichiometric ratio of H2/O2 (2:1) initial gas production from pure water. This study provides a simple and cost-effective technology for direct water splitting that may generate hydrogen fuels by scavenging energy wastes such as noise or stray vibrations from the environment. This new discovery may have potential implications in solving the challenging energy and environmental issues that we are facing today and in the future.