Under the direction of University Professor Geoffrey Ozin of the Department of Chemistry in the University of Toronto’s Faculty of Arts & Science, a group of advanced materials chemistry researchers has made a major advancement in the use of light to convert carbon and carbon dioxide (CO2) into carbon monoxide (CO).
University Professor Geoffrey Ozin said the research aims to decarbonize the generation of industrial chemicals. Image Credit: University of Toronto
Ozin and colleagues present the process, which offers an alternative to carbon-intensive methods of manufacturing industrial carbon monoxide, in a report published in Energy and Environmental Science.
Both carbon monoxide and carbon dioxide pose risks to human health, and elevated carbon dioxide levels in the atmosphere contribute to climate change through global warming. Despite this, both gases play crucial roles in the large-scale manufacturing of essential commodity chemicals and fuels.
For instance, in the chemical industry, carbon monoxide is used as a feedstock for the production of polymers, medicines, methanol, and acetic acid. It is used in the food industry to acidify carbonated drinks and package fresh meat items. Its applications are numerous and include everything from metal refining and rust removal to acting as a vital part of infrared lasers.
For these kinds of uses, carbon monoxide is usually produced by thermally driven processes like partial oxidation of natural gas and gasification of coal. These processes have a substantial carbon footprint and produce a lot of hazardous byproducts.
The environmentally friendly method being developed by Ozin’s team uses light for the production process instead of burning fossil fuels to produce carbon monoxide. This is combined with the newly popular method of employing carbon dioxide as a chemical feedstock.
The study demonstrates that a natural carbon source may be used to facilitate this conversion process. In addition to the air, it may originate from fossil fuel emissions, biochar produced by slowly burning agricultural biomass, or specialized technology for air capture, storage, and release.
Using this captured carbon dioxide, the U of T team uses a light-powered process that converts it to carbon monoxide in a less energy- and chemical-intensive manner than the identical reaction driven by heat.
The CO generated photochemically by this means can justifiably be called green.
Geoffrey A. Ozin, Professor, Department of Chemistry, University of Toronto
At the helm of U of T's interdisciplinary Solar Fuels Cluster, Ozin, the Principal Investigator, envisions steering the research group toward transitioning chemical and petrochemical industries from traditional fossil fuel dependence. Their goal is to facilitate a shift towards eco-friendly methods, utilizing waste carbon dioxide and carbon, powered by solar-driven processes in refineries.
By this means, it should prove feasible to decarbonize the generation of commodity chemicals and fuels, motivated by the desire to ameliorate greenhouse gas-induced climate change and global warming.
Geoffrey A. Ozin, Professor, Department of Chemistry, University of Toronto
Earlier attempts to create carbon monoxide in an environmentally benign manner used thermal steam-gasification of waste materials, biomass, or fossil fuels. This process involved superheating the required feedstock with steam in order to make carbon monoxide.
But this has a big carbon footprint and can be hindered by things like tar pollution and melting ash. Dioxins and furans, two pollutants linked to combustion, are produced throughout the process, which calls for clean oxygen infusions.
Instead, Ozin’s group is leading the way in photochemistry techniques that produce fewer pollutants while operating at ambient temperature.
Improvements in photoreactor efficiency, battery performance, solar concentration optics, and light-emitting diodes are expected to make green carbon monoxide generation more economically feasible. These technological advances are essential to making green carbon monoxide generation competitive with the current thermochemical and electrochemical production methods.
There is a chance to lessen the environmental impact of producing this hazardous but necessary industrial chemical by switching from processes that burn fossil fuels to those that use renewable energy, unwanted atmospheric carbon monoxide, and waste forms of carbon. This shift will also help to create jobs in the green sector.
Journal Reference:
Viasus Pérez, J, C., et al. (2023). Carbon photochemistry: towards a solar reverse boudouard refinery. Energy & Environmental Science. doi/2023/ee/d2ee03353d/unauth#fn2