August 30, 2016 | 1 Comment
Scientists from the University of Toronto (UT) believe they’ve found a catalytic way to convert CO2 emissions back into energy-rich fuel precursor. They have developed a process to convert these emissions in a carbon-neutral cycle that uses a very abundant natural resource: silicon. Readily available in sand, it’s the seventh most-abundant element in the universe and the second most-abundant element in the earth’s crust.
The idea of converting carbon dioxide emissions back into energy isn’t new: there’s been a global race to discover a material that can efficiently convert sunlight, carbon dioxide and water or hydrogen to fuel for decades. However, the chemical stability of carbon dioxide has made it difficult to find a practical solution.
Geoffrey Ozin, a chemistry professor in UT’s Faculty of Arts & Science, the Canada Research Chair in Materials Chemistry and lead of U of T’s Solar Fuels Research Cluster said, “A chemistry solution to climate change requires a material that is a highly active and selective catalyst to enable the conversion of carbon dioxide to fuel. It also needs to be made of elements that are low cost, non-toxic and readily available.”
The hydride-terminated silicon nanocrystals – nanostructured hydrides for short – have an average diameter of 3.5 nanometers and feature a surface area and optical absorption strength sufficient to efficiently harvest the near-infrared, visible and ultraviolet wavelengths of light from the sun together with a powerful chemical-reducing agent on the surface that efficiently and selectively converts gaseous carbon dioxide to gaseous carbon monoxide.
The potential result is a fuel precursor without harmful emissions.
Ozin said, “Making use of the reducing power of nanostructured hydrides is a conceptually distinct and commercially interesting strategy for making fuels directly from sunlight.”
The UT Solar Fuels Research Cluster is working to find ways and means to increase the activity, enhance the scale, and boost the rate of production. Their goal is a laboratory demonstration unit and, if successful, a pilot solar refinery.
While impressive, there are some big issues to work out. There is that oxygen atom product that seems to be oxidizing the catalyst. There is no method yet to drive the nanostructured hydrides production to a commercial scale volume. Those are just two matters that will be getting intense attention.
But the breakthrough value here is cost. The active agent here is silicon, an abundant and low cost material. This research crashes most all other venues to recycling CO2. This is the tech for research future until something better is discovered. That may not be needed, as this technology has just emerged with lots of room to improve.