Harnessing the Sun

Posted on Tuesday, August 25th, 2020

Image showing field with large solar panels during sunset.
The solar energy hitting the Earth in one hour could satisfy human energy needs for a year. We need a way to capture that energy.

Chemistry researchers uncover novel technique to better understand how to harness solar energy.

The global population is growing, and with it, the amount of energy that we consume. It is estimated that humans use over one million terajoules of energy every day. For perspective, a Boeing 747 airplane can cross the Atlantic Ocean using just one terajoule. These immense energy demands are driving rising greenhouse gases in the Earth’s atmosphere. We need a more sustainable way to produce and store energy.

Chemistry professor Aicheng Chen and his research team at the University of Guelph are exploring a promising method to harness energy from the sun called photoelectrochemical water splitting. This method involves a chemical reaction in which sunlight breaks down water into oxygen and hydrogen. During this process, the solar energy is converted into chemical energy, which is then stored through chemical bonds with hydrogen molecules. Ultimately, the hydrogen can be used for fuel. However, before scientists can implement water splitting for large-scale energy production and storage, they need to understand the chemical process better. Chen and his team have demonstrated a novel technique that will help—scanning photoelectrochemical microscopy. This technique analyzes the small-scale behaviours of an electrode, the conductor that carries current, by scanning its surface using a focused beam of photons under an applied electrode potential.

The U of G researchers experimented with this technique by scanning a nanostructured bismuth vanadate surface, which is a semiconductor with a strong response to visible light. The generated high-resolution, three-dimensional images provide insight into how the water oxidation reaction occurs—information that will help researchers design systems that can produce and store hydrogen as an alternative energy source.

“We have developed an advanced tool that scientists can use to better understand the processes occurring during the water splitting reaction,” explains Chen. “The more we understand the process, the closer we come to being able to implement it to capture and store solar energy. With the ability to harness the sun’s power, we would have clean, renewable solar energy.”

This work was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada (NSERC).

A. Chen holds a Tier 1 Canada Research Chair in Electrochemistry and Nanoscience.

Chen S, Prins S, Chen A. Patterning of BiVO4 Surfaces and Monitoring of Localized Catalytic Activity Using Scanning Photoelectrochemical Microscopy. ACS Appl. Mater. Interfaces. 2020 Mar 20. doi: 10.1021/acsami.9b22605

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