logo
menu

Innovations in the production of biofuels in bid to cut emissions

The rising presence of carbon dioxide in the atmosphere is not a new problem and it is widely known. Last year in 2019, a new record amount of carbon dioxide was recorded in the atmosphere at around 409 ppm, and it will be increasing every year if past trends continue. Carbon dioxide emissions have also been increasing every year with an increase of approximately 12 billion tons of emissions over the period of 1990 to 2020 [1].
The good news is that many researchers have exploited the fact that carbon dioxide is a very useful precursor in the production of more sustainable fuels, which can address not only the emissions issue but also the issue of the sustainability of fossil fuels.
This article highloghts some recent examples of innovations using catalysis or other methods to convert carbon dioxide into fuels.
There have been some cases where the conversion of carbon dioxide to fuel has been carried out using bacteria. In one example from Columbia University, a type of bacteria called N. europaea uses energy from ammonia and carbon dioxide to make liquid biofuels inside of a reverse microbial fuel cell (R-MFC).
Usually, biofuels would be made from biomass which gets its energy from converting solar energy through photosynthesis, but this method skips that energy-inefficient step.
Electricity can put ammonia back into the system when the ammonia feed first runs out, which turns this process into an efficient, fuel-making cycle.
It is reported that the liquid fuel created here can be up to 10 times more efficient than biofuels we currently have.
Another very similar process developed at Harvard University can also skip photosynthesis steps and can use bacteria in a bacterial reverse fuel cell to directly convert carbon dioxide to electrofuels.
Electrofuels include hydrocarbon and alcohol-based fuels that are made using electrical energy. In this case, the bacteria called Shewanella gets energy directly from electrical conductors that are powered by the energy absorbed through solar panels.
A key benefit to this development is that the electrofuels produced can serve the same function as most current gasoline and diesel fuels and also the electrofuel molecules do not need any further treatment when they are extracted from the bacterial culture [2].

There are also a few industrial examples of carbon dioxide-to-fuel conversion. Audi AG in Germany was constructing a plant that will convert renewable energy and carbon dioxide into synthetic methane.
This methane fuel can not only be used to power Audi vehicles in Germany, but it can also be transported across the nation’s natural gas network to power many other vehicles currently in use.
Researchers from Mitsubishi Heavy Industries in Japan have worked out a method to capture carbon dioxide from one of their coal-fired power plants and use the carbon dioxide, along with hydrogen coming from water electrolysis, to produce methanol and then convert the methanol to dimethyl ether.
Dimethyl ether is renewable and can be used as diesel fuel. ExxonMobil took a similar approach where they announced in a news statement the potential for their methanol-to-gas process. Their process can use carbon dioxide as a feedstock to make methanol, which they say that they can either refine this to a very clean fuel or they can use the methanol to make dimethyl ether [2].
Last year, researchers from Rice University in Houston designed a fuel cell that will convert carbon dioxide to clean liquid fuel solutions, which include formic acid, ethanol, and n-propanol.
To produce the formic acid, the researchers did not take the traditional path of using liquid electrolytes but instead chose to employ solid electrolytes composed mainly of inorganic compounds.
The researchers chose to use the bulky metal bismuth to make up their cathode catalyst, which is very selective towards the formic acid formation and also highly scalable. Negatively charged formate is produced as carbon dioxide passes through the cathode, then the formate is combined with protons coming from the solid electrolyte, after which formic acid is created. Electricity to power the cell is provided externally by either a photovoltaic cell, wind turbine, or some other renewable source. The researchers also found an efficient way to produce ethanol and n-propanol using a copper catalyst [3,4].

A similar approach was taken by other scientists from Argonne National Laboratory and Northern Illinois University. They designed an electrocatalyst for the conversion of carbon dioxide to ethanol that can also utilize power from a renewable source of electricity such as wind or solar power. Ethanol is widely used as a fuel source today and the researchers claim that their catalyst is highly selective and low cost. The catalyst itself is made of copper which is dispersed onto carbon powder and it gets activated by an electric field that can be provided by renewable electricity [5].
The examples provided here show a large amount of creativity used to come up with potential solutions for the issue of increasing carbon dioxide emissions. This field of research of using carbon dioxide to make things that can be very useful to us in a renewable fashion seems to be very active and does not show any signs of slowing down. The path to converting carbon dioxide to fuels is not very clear-cut and it can take many different forms, such as using bacteria in an R-MFC, collecting carbon dioxide released from coal-fired power plants, or creating catalysts that can be coupled with renewable electricity to do the job. This research provides modest yet rather meaningful steps in addressing the problem of increasing emissions in our atmosphere.




References
[1] Rebecca Lindsey. “Climate Change: Atmospheric Carbon Dioxide.” NOAA Climate.gov. August 14, 2020. https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide
[2] Ibram Ganesh. “Electrochemical conversion of carbon dioxide into renewable fuel chemicals – The role of nanomaterials and the commercialization.” Renewable and Sustainable Energy Reviews, 59, 2016, 1269–1297.
[3] Wang, H, et al. “Continuous production of pure liquid fuel solutions via electrocatalytic CO2 reduction using solid-electrolyte devices.” Nature Energy, vol. 4, September 2019, 776-785.
[4] Mike McRae. “Engineers Build a Device That Effectively Transforms CO₂ Into Liquid Fuel.” Sciencealert.com, 8 September 2019. https://www.sciencealert.com/engineers-build-a-new-kind-of-device-that-effectively-transforms-co2-into-liquid-fuel#
[5] Joseph E. Harmon. “Turning carbon dioxide into liquid fuel.” Argonne National Laboratory, 5 August 2020. https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel
This article was written by Dr. Raj Shah and Mr. Nathan Aragon








124 queries in 0.476 seconds.