Toshiba's photo-electrochemical system achieves 0.48% efficiency converting CO2 into ethylene glycol

October 31, 2016, Toshiba Corporation
Toshiba's photo-electrochemical system achieves 0.48% efficiency converting CO2  into ethylene glycol
Credit: Toshiba Corporation

Toshiba has achieved an advance in photo-electrochemical processing that converts carbon dioxide directly into ethylene glycol with an efficiency of 0.48%. Ethylene glycol is a useful and versatile industrial raw material that can be used to manufacture polyester fibers, PET bottles and antifreeze formulations.

The high conversion rate is due to Toshiba's development of a silicon-based photovoltaic cell as the electricity source for a molecular catalyst to electrochemically reduce in an aqueous solution and convert it into . The technology was presented at the PRiME 2016 international conference held in Honolulu, Hawaii, on October 2-7, 2016.

Rising concentrations of carbon dioxide in the atmosphere are recognized by the International Panel on Climate Change and other expert bodies as a primary cause of climate change, and this, along with growing concerns for fossil fuels, is stimulating efforts to develop renewable and low-carbon energy sources. In parallel, efforts are also being made around the world to develop photo-electrochemical cell technology for converting CO2 into chemical energy, as a countermeasure against both climate change and fossil-fuel concerns.

Previously reported electrochemical catalyst have converted carbon dioxide into two-electron reduction products, such as carbon monoxide and formic acid, stimulating a search for catalysts that support more complex reduction reactions and produce a multi-electron reduction substances. This approach is seen in the use of a copper catalyst to trigger direct conversion into hydrocarbons. However, this approach also generates a large quantity of by-products, a problem in itself.

Toshiba's photo-electrochemical system achieves 0.48% efficiency converting CO2  into ethylene glycol
Credit: Toshiba Corporation

Toshiba's work in molecular catalysts has led to the development of a photo-electrochemical system (patent pending) that uses a silicon-based photovoltaic cell as the source of electricity for molecular catalysts to electrochemically reduce carbon dioxide into ethylene glycol. Conversion to ethylene glycol using the photo-electrochemical system produces an energy conversion of 0.48%.

The newly developed catalyst is an imidazolium salt derivative adsorbed at high density onto a metal surface. When carbon dioxide molecules interact with the derivative, a reaction not previously achieved occurs, a result attributed to the molecular catalyst promoting both a direct reaction with the carbon dioxide and serving as a reaction field for multi-electron reduction reactions.

The ethylene glycol generated by the system is a valuable and versatile industrial raw material that can be used in the manufacture of PET bottles, polyester fibers and resins. Toshiba will continue to develop the technology, targeting commercialization of a highly efficient system for producing industrial raw materials by the 2020s.

Explore further: New molecular catalyst for artificial photosynthesis converts carbon dioxide directly into ethylene glycol

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Fredrickson
not rated yet Nov 08, 2016
Technology like this needed on Mars
to build infrastructure
regolith resin bricks
sandbags & insulation

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