Sun-Powered System Turns Pollution into Fuel

By Mark Miller

New research shows that the plastics we use and the carbon dioxide (CO₂) we produce can be reborn as fuels and useful products. A ScienceDaily article reports that University of Cambridge researchers have developed a system that harnesses sunlight to simultaneously transform plastic into glycolic acid, a chemical compound used in cosmetics, and CO₂ into syngas, synthetic gas that’s a key component of liquid fuels.

Dynamic Duo

The system is a chemical reactor with two separate compartments: one for plastics and another for greenhouse gases, according to a report published in the journal Anthropocene. The compartments are separated by a membrane with an electrode on either side. A negative electrode is used for CO₂ conversions and a positive electrode for plastics. Perovskite—an alternative to silicon for absorbing sunlight to create electricity—coats the negative electrode to fuel the two-way system.

Catalytic Advantages

Catalysts are used to facilitate the reactions and the system can be adjusted to produce different products by changing catalysts. The team at Cambridge considers this adjustability an important advantage. “What’s so special about this system is the versatility and tuneability—we're making fairly simple carbon-based molecules right now, but in future, we could be able to tune the system to make far more complex products, just by changing the catalyst,” explained Subhajit Bhattacharjee, PhD, a co-first author of the research published by the Cambridge team.

Another advantage is that the system was able to produce its results at a higher rate than conventional photocatalytic conversions. “Generally, CO₂ conversion requires a lot of energy, but with our system, basically you just shine a light at it, and it starts converting harmful products into something useful and sustainable,” said Motiar Rahaman, PhD, also a co-first author.

Fueling Solar Recycling

It’s the first time these transformations have been combined into a single process using a solar-powered reactor, and it may mark a significant advancement in how pollutants can be reused.

“Developing a circular economy, where we make useful things from waste instead of throwing it into landfill, is vital if we’re going to meaningfully address the climate crisis and protect the natural world,” said Professor Erwin Reisner, PhD, senior author of the research.

The Cambridge team is planning to produce more complex molecules as they further develop the reactor, and they say similar techniques could be used to create entire solar-powered recycling plants.

“With our system, basically you just shine a light at it, and it starts converting harmful products into something usefulandsustainable.”