One step closer to sustainable hydrogen production

They work in a field called photocatalysis, which, at its most basic, uses light to speed up chemical reactions. They’ve come a step closer to such a feat by tailoring the structure of a material called titania, one of the best-known photocatalysts, to hasten hydrogen production from biomass-derived compounds.

Through a five-year collaboration with Drexel University, the University of Trieste in Italy, the University of Cadiz in Spain and the Leibniz Institute for Catalysis in Germany, the researchers determined that lengthening nanorods to 50 nanometers, a size 1,000 times smaller than the diameter of a hair, increased the hydrogen production rate of a rare form of titania called brookite, only accessible at the nanoscale.

Using this unique crystal structure and controlling the nanorod dimensions offer new avenues for engineering the material’s activity, and, because the process is theoretically simple to replicate, even at a large scale, it could have real implications for the future of clean energy and sustainable hydrogen production.

The researchers published their results in the journal Proceedings of the National Academy of Sciences.

“These insights are one more piece in an important puzzle as we work to harness the phenomena exhibited by Earth’s materials,” said Murray, a Penn Integrates Knowledge Professor and the Richard Perry University Professor of Chemistry and Materials Science and Engineering.

One such material comes from the sun. “One idea behind photocatalysis is, what if we could make hydrogen using sunlight from abundant compounds? We wouldn’t have to produce it from fossil fuels, which has global warming effects,” said Cargnello, a former Penn postdoc who is now a Stanford assistant professor of chemical engineering.

“If we could get that hydrogen from a renewable source, then the entire process would be totally sustainable” said Paolo Fornasiero, a University of Trieste professor of chemical and pharmaceutical sciences who collaborated with the Murray team on hydrogen measurements.

On its face, the process sounds straightforward: Titania absorbs sunlight, which initiates a chemical reaction that generates hydrogen. But the vehicles responsible for this response, called electrons and holes, tend to jump the gun, reacting with each other almost immediately due to their opposite charges.

Read More: https://www.sciencedaily.com/releases/2016/03/160330184410.htm