A study led by PhD researcher Xiao Lu at the University of Adelaide explores how solar-powered systems can transform plastic waste into hydrogen, syngas and other industrial chemicals. The findings, published in Chem Catalysis, point to a potential pathway for building a circular and sustainable economy.

With global plastic production exceeding 460 million tonnes annually — much of it ending up in landfills and oceans — researchers say the material’s high carbon and hydrogen content makes it a valuable, yet underutilised, resource.

“Plastic is often seen purely as waste, but it also holds significant potential,” Lu said, noting that efficient conversion using sunlight could simultaneously address environmental damage and energy demand.

How the process works

The technology relies on a method known as solar-driven photoreforming. It uses photocatalysts — light-sensitive materials — to break down plastics at relatively low temperatures. This process generates hydrogen, a clean fuel that produces no emissions at the point of use, along with other commercially useful chemicals.

Compared to conventional hydrogen production methods such as water splitting, plastic-based photoreforming is considered more energy-efficient because plastics are easier to oxidise, making the process more viable for scale.

Senior researcher Xiaoguang Duan said recent experiments have delivered promising outcomes, including sustained hydrogen production, formation of acetic acid and even diesel-range hydrocarbons. Some systems have operated continuously for over 100 hours, demonstrating improving stability.

Barriers to large-scale deployment

Despite encouraging progress, the study highlights several technical hurdles that must be addressed before commercial rollout.

One of the biggest challenges is the heterogeneous nature of plastic waste. Different polymers react differently during conversion, while additives such as dyes and stabilisers can disrupt chemical processes. This makes sorting and pre-treatment critical for efficiency.

Another concern lies in the durability of photocatalysts. These materials must remain stable under harsh chemical conditions, yet many current designs degrade over time, limiting long-term use.

“There remains a gap between laboratory success and real-world application,” Duan said, stressing the need for more robust catalyst systems and scalable designs.

The road ahead

Separating the end products — typically a mix of gases and liquids — also remains energy-intensive, reducing the overall sustainability advantage. To overcome this, researchers are calling for integrated solutions combining improved catalyst design, advanced reactor engineering and system optimisation.

Emerging approaches include continuous-flow reactors, hybrid systems that combine solar with thermal or electrical inputs, and smarter monitoring tools to enhance efficiency.

The research team believes that with sustained innovation, solar-powered plastic-to-fuel technologies could become a cornerstone of future low-carbon energy systems.

“This field is advancing rapidly,” Lu said. “With the right breakthroughs, it has the potential to transform waste into a valuable energy resource while reducing environmental harm.”