Engineering news
Researchers at MIT have developed a catalyst material that converts carbon dioxide (CO2), to carbon monoxide (CO), as a way to produce liquid fuels from greenhouse gases.
The team developed a tunable catalyst in the form of a highly porous silver electrode material. MIT said that by tuning the dimensions of the material’s pores they could get the system to produce a selective, specific conversion pathway that gives the desired proportion of CO in the end-product “without modifying the surface active site chemistry”.
The porous material, called silver inverse opal, can be made by depositing tiny polystyrene beads on a conductive electrode substrate, then electrodepositing silver on the surface and dissolving away the beads, leaving pores whose size is determined by that of the original beads. Because of the way spheres naturally organise themselves when packed together, this method produces a honeycomb-like structure of hexagonal cells.
Varying the thickness of the porous catalyst produces a double effect. As the porous inverse opal get thicker, the catalyst promotes the production of CO from CO2 by up to three times, while also suppressing an alternative reaction, the production of hydrogen gas, by as much as tenfold. Using this combined effect, production of CO can be easily varied to make up anywhere from 5-85% of the reaction’s output.
Much work still remains for this to become a practical approach to manufacturing transportation fuels, according to MIT. However, the study provides insight into how to engineer carbon-neutral technologies for replacing existing fossil-fuel systems while still being able to use all of the existing infrastructure of gas stations, delivery vehicles, and storage tanks without adding net greenhouse emissions to the atmosphere.
The research is part of the MIT Energy Initiative’s Low-Carbon Energy Centres, established as part of the institute’s plan for action on climate change.
The study appears in the journal Angewandte Chemie.