Reversing the negative results of combustion – by converting the products of combustion to ethanol – is a long-held dream that is now a step closer to reality.
Government scientists at Oak Ridge National Laboratories in the United States reported reversing the process of burning ethanol to create carbon dioxide in September, 2016.
The researcher’s invention involves passing an electric current through graphene. The reaction ensues in the presence of crystalline copper, water, nitrogen gas and carbon dioxide. This process takes place at room temperature and normal atmospheric pressure–while utilizing Nanotechnology.
Nanotechnology & Chemistry Research
Nanotechnology pushes research towards quicker and more efficient reaction schemes. Scientists realize that molecules can be manipulated more like macroscopic objects while utilizing their quantum mechanical descriptions.
In his groundbreaking lecture (conceptualizing the discipline of Nanotechnology) in 1959, There is Plenty of Room at the Bottom, Dr. Richard Feynman states:
…But I am not afraid to consider the final question as to whether, ultimately – in the great future – we can arrange the atoms the way we want; the very atoms, all the way down! What would happen if we could arrange the atoms one by one the way we want them (within reason, of course; you can’t put them so that they are chemically unstable, for example)… … principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big. …
Instead of using abstract theories of bonds as electrons in molecules shuffling about, we can now conceptualize chemical reactions as physical objects moving about.
Much of present nanotechnology centers around carbon and optimizing quantum mechanical equivalents of known reactions, such as how copper catalyzes ethanol formation from carbon dioxide.
Adding copper or other metals enables researchers to produce ethanol from carbon dioxide in much the same way that researchers utilize inorganic species as catalysts in chemical synthesis (employing inorganic molecules and atoms changes chemical reactivity).
A Short Definition of Combustion
Carbon Dioxide results from the process of combustion. Combustion is explained simply as the burning of a substance such as ethanol (drinking alcohol) or gasoline.
A precise definition comes from The American Heritage Dictionary 5th ed.
A chemical change, especially through the rapid combination of a substance with oxygen, producing heat and, usually, light.
Expressing combustion of ethanol in a chemical equation gives:
Ethanol from Carbon Dioxide?
While combustion breaks chemical bonds, releases energy and produces numerous product molecules, reversing the process is not impossible. Problems surrounding the reversal of combustion come about from the enormous amount of energy that would be required. The brute force required to put carbon dioxide and water back to their original forms (ethanol and oxygen) is seemingly infinite. Imagine trying to take a burning ember and confining the smoke and returning the smoke back into its original form without the fire. ‘Reversing combustion’ is not quite as easy as it seems.
A difficult prospect such as this means we must think outside of the box. The workers at Oak Ridge National Laboratories discovered the process through a serendipitous stroke of lab work. Lead investigator, Dr. Adam Rondinone, told Decoded Science:
We were testing a new nanostructured electrocatalyst for possible methane or methanol production, which is the expected product based on the current understanding of these reactions. We instead detected large amounts of ethanol. The initial discovery was about 2 years ago. We spent the next year replicating the reaction many times under different conditions to better understand the mechanism and optimum conditions.
How to Synthesize Ethanol from Carbon Dioxide
Researchers at Oak Ridge National Laboratories utilized graphene — a form of carbon visually resembling chicken wire. The researchers manipulate the graphene by passing an electric current through it within a nitrogen gas atmosphere.
By making an electrode from graphene — passing an electric current through the material, they change graphene from a planar substance (chicken wire) to one that is puckered and resembles a crumbled sheet of paper. The copper particles sit in a nest-like manner within the ‘crumbled carbon sheet.’
Adding carbon dioxide gas to the reaction vessel allows the process to proceed to product. According to Dr. Rondinone:
The role of the copper is to present an initial adsorption site for the CO2 molecule and to provide a site for dimerization” . “Without the copper, controlled dimerization does not occur (although minor polymerization does occur).
Optimized Carbon-Copper Yields Mostly Ethanol?
Computational simulations performed at the Oak Ridge National Labs discovered that optimized copper could perform the needed conversion. While the conversion to ethanol, without modifications to copper or graphene, yielded many products–the optimized carbon/copper surface yielded mostly ethanol.
Copper is a superior conductor of electricity, and in the conventional reaction, it catalyzes the reaction to the desired product. Catalysts push reactions that would not normally go to completion–normally reactions that do not complete do so because of insurmountable energy barriers. Catalysts open doors to pathways that are efficient and use less energy to produce the end results.
The Arrow of Time and Re-engineering Greenhouse Gases?
Possessing the ability to change carbon dioxide to its original form may provide a major step to removing greenhouse gases from the atmosphere. The researchers at ORNL estimate that the eventual scale-up of the reaction could remove massive quantities of carbon dioxide from the atmosphere.
Visualize utilizing the scheme outlined as a veritable mimic to photosynthesis–producing a hydrocarbon from carbon dioxide… This may just give us a fighting chance in the battle against man-made climate change.