Carbon Nanofibers Offer Cheap Way to Convert CO2 To Fuel
File this one under “I” for It takes a thief to catch a thief. A research team at the University of Illinois at Chicago is on track to developing a low-cost method for reducing carbon dioxide to carbon monoxide, which puts it one step away from creating synfuels including synthetic gasoline. The secret sauce is the use of carbon nanofibers in combination with another catalyst.
If the new UIC carbon reduction system bears out on a commercial scale, it would provide a direct financial incentive for carbon emitters to capture and reclaim carbon dioxide as a valuable byproduct, rather than enabling it to enter the atmosphere as a greenhouse gas.
Using Carbon Nanotubes To Convert Carbon Dioxide
Reducing CO2 to CO is far from a new thing, but until now the process has been typically carried out using a single, expensive catalyst.
The UIC team started with the idea that since CO2 reduction is a two-step reaction, it might be more efficient and less costly to develop different catalysts for each step.
They got the efficiency part right on an early try using an ionic liquid as a catalyst for the first step (ionic liquid refers to a salt in a liquid state) and silver for the second step, but that still left cost as an obstacle.
The next challenge was to find a cheap substitute for the silver catalyst, which the team achieved by doping carbon nanofibers with nitrogen.
That wasn’t exactly a stab in the the dark, since according to UIC writer Jeanne Galatzer-Levy the use of nitrogen-doped carbon nanofibers is fairly common.
With nitrogen-doped carbon fibers as a co-catalyst for the ionic liquid, the overall reaction exceeded expectations, achieving an efficiency greater than silver.
As for the reason behind the stellar performance, that turned out to be a bit of a surprise. When the reaction was analyzed, the UIC team discovered that the nitrogen dopant was not the critical factor, it was the carbon atom.
Wait For It…Graphene!
That discovery could turn out to be the eureka moment for the UIC team as described by UIC’s Bijandra Kumar, who co-first-authored the research paper (just published online in Nature Communications and slated for the print edition, too):
…one can imagine that using atomically-thin, two-dimensional graphene nano-sheets, which have extremely high surface area and can easily be designed with dopant atoms like nitrogen, we can develop even far more efficient catalyst systems.
Did he just say graphene? Yes, he did. Graphene, an atom-thin sheet of carbon with unique and powerful characteristics, has been popping up all over the clean tech field, including photovoltaic cells, so it wouldn’t be much of a stretch to put it to work in carbon dioxide reduction.
When Life Hands You Carbon Dioxide, Make Lemonade
The whole point of this is to get a cheap source for syngas as a precursor to creating fuels, with the co-aim of managing carbon emissions.
That’s just one strategy for reclaiming and re-using carbon dioxide. For a different angle, take a look at the sustainable winery at UC-Davis, which includes a system for converting CO2 to calcium carbonate, aka chalk.
As for carbon monoxide, one approach is illustrated by the New Zealand company LanzaTech, which has developed a microbe-based carbon conversion system that can yield fuels and plastics. The company recently won a $4 million U.S. Department of Energy grant to bump up development of the system into mainstream use.
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