• The Marie Skłodowska-Curie Actions (MSCA)-funded E-PLUS project will develop advanced catalysts to make plastic upcycling more economically attractive while lowering the energy cost required for hydrogen production.

For most of us, recycling plastic has become second nature. We separate bottles, food containers and packaging, believing they will be transformed into new products.

Yet despite decades of recycling initiatives, only around 9% of the roughly 380 million tons of plastic waste produced globally each year is recycled. The vast majority is incinerated, releasing large amounts of carbon dioxide and toxic by-products, threatening ecosystems and human health while wasting valuable resources, sent to landfill, or ends up polluting the environment in other ways.

Researchers are therefore beginning to ask a different question. Rather than simply recycling plastic, can we transform it into something even more valuable?

This is precisely the challenge being addressed by the new E-PLUS project at IMDEA Materials Institute led by MSCA postdoctoral fellow, Dr. Xinzhang Lin and supervised by Prof. Harun Tüysüz.

E-PLUS aims to develop a new electrochemical process to convert polyethylene terephthalate (PET), the world’s most widely used polyester plastic, into glycolic acid, a valuable chemical used in cosmetics, pharmaceuticals and biodegradable materials.

“Existing recycling technologies play an essential role in plastic-waste management, but each route has specific limitations,” explains Dr. Lin. “Mechanical recycling is relatively simple and energy-efficient, but it generally requires clean and well-sorted feedstocks, and repeated processing can gradually reduce material quality.”

“Chemical recycling, meanwhile, can require demanding reaction conditions, extensive purification, or high capital and energy inputs, which can limit its economic competitiveness.”

Rather than simply recovering PET, E-PLUS seeks to increase its value by converting it into glycolic acid, a higher-value chemical. However, achieving high selectivity toward the high-value product glycolic acid still relies heavily on precious metal catalysts.

“Instead of viewing plastic waste as an environmental burden, we want to demonstrate that it can become a valuable feedstock for producing both high-value chemicals. Effectively, turning waste into wealth” adds Dr. Lin.

However, transforming plastic waste into a valuable chemical is only one part of the story.

Using plastic waste to facilitate green hydrogen production

Green hydrogen is widely regarded as one of the most promising clean fuels for the energy transition, but producing it remains highly energy intensive.

Conventional water electrolysis splits water into hydrogen and oxygen through two coupled half-reactions. Hydrogen, the desired product, is generated at the cathode, while the oxygen evolution reaction (OER) takes place at the anode to maintain charge balance.

However, this reaction is kinetically sluggish, accounting for a major portion of the electrical energy consumed, making it the primary bottleneck for overall efficiency.

To reduce electricity consumption, E-PLUS replaces the oxygen evolution reaction with the selective oxidation reaction of PET-derived ethylene glycol into glycolic acid.

This alternative reaction requires significantly lower electricity consumption while simultaneously producing hydrogen.

“The two benefits, therefore, arise from the same electrochemical process,” explains Dr. Lin. “PET-derived ethylene glycol is converted into valuable glycolic acid at the anode, promoting plastic waste upcycling, while green hydrogen is efficiently produced at the cathode, contributing to climate change mitigation.”

Designing catalysts at the atom scale

Achieving these ambitious goals will depend on developing a new generation of single-atom catalysts, which maximise the use of precious metals by ensuring almost every metal atom participates in the reaction.

The challenge lies in keeping these isolated metal atoms stable while carefully modulating their electronic properties so that the reaction selectively produces glycolic acid instead of less valuable by-products.

To achieve this, the project combines advanced catalyst design with theoretical modelling to identify the most effective catalyst compositions and structures before they are synthesised experimentally.

“If successful, these catalysts could combine lower noble-metal usage with high activity, high glycolic acid selectivity, making them highly promising for efficient PET upcycling,” says Dr. Lin.

Researchers aim to demonstrate the technical feasibility of the process by developing catalysts that use minimal amounts of noble metals while maintaining high activity, achieving a glycolic acid selectivity of above 98%, and operating stably for more than 1,000 hours.

“We hope that this interdisciplinary approach will provide both fundamental scientific insights and a technical foundation for future scale-up and industrial evaluation,” concluded the researcher.