A recent flurry of articles and studies has looked at the CO2 recycling process, describing it as a means of turning “garbage…into fuel”. Though there are many approaches mentioned or studied, it was one by from 2011 that caught the eye of Science Magazine. In one of their spotlights on CO2 recycling, they described the results that a group of “researchers led by Richard Masel, a chemist and CEO of Dioxide Materials in Boca Raton, Florida” shared. They were facing problems with the overpotential that occurs when trying to convert a CO2 molecule, since the CO2 molecule is extremely stable and breaking its bonds has historically required so much energy that recycling CO2 has been viewed as uneconomical, despite the danger CO2 greenhouse gas emissions pose. Dioxide Materials TM developed an electrochemical co-catalyst technology that uses 50% less energy to break the CO2 bonds and looking to improve ion exchange membranes to overcome the issue.and now provide cost-effective electrochemical pathways for renewable fuels and chemicals.
They looked at the use of silver with iridium oxide catalysts and a liquid elesctrolyte known as imidazolium. This resulted in an overpotential of just .17 volts but did not address the issue of corrosion or the high costs of ionic liquids. Their anion exchange membranes are the end result and they are poised to revolutionize the process, and the industry.
After all, as reported, “devices using them produced CO with an efficiency nearly double that of the next best membrane…[and] with recent upgrades, their cells can transform CO2 to CO at double the rate of other CO2-splitting electrolyzers of a comparable size, which could help them process large volumes of CO2 when scaled up… the company’s devices remain stable and undeteriorated after 6 months of continuous operation.”
What this indicates is something with commercial capability, and why their anion exchange membranes have exceeded the typical “postage stamp” dimensions and are now available in much larger sizes to enable much more substantial CO flux. They are even exploring anion exchange membranes capable of even greater capacity, such as swaths functional in a reel-to-reel process.
Even more impressive is that their systems can work without the precious or rare metals thanks to enhancements in their electrolyzer application.
Patented under the trade name Sustainion®, the imidazolium functionalized styrene polymer membranes offer superior conductivity and high current densities at low voltage. With their long lifetime and higher currents, they are highly conductive above 100 mS/cm under alkaline conditions at 60 °C, stability for thousands of hours. They offer a physical mechanical stability useful for many different applications, and currently sustain lifetimes of more than 4000 hours in CO2 electrolyzers at high current densities.
Enabling commercial recycling of CO2 outputs, reducing renewable energy curtailments, and converting “garbage” into viable gas or jet fuel feedstocks is now possible.
