A team of Korean scientists has developed an innovative green technology that transforms plastic waste into clean hydrogen fuel using only sunlight and water.

Researchers at the Institute for Basic Science (IBS) Center for Nanoparticle Research, led by Professor KIM Dae-Hyeong and Professor HYEON Taeghwan of Seoul National University, announced the successful development of a photocatalytic system that produces hydrogen from PET bottles. The key innovation lies in wrapping the photocatalyst in a hydrogel polymer, which helps it float on water and stay active even under harsh environmental conditions.

Hydrogen is gaining attention as a next generation clean energy source. However, the most common method for producing it—methane steam reforming—consumes large amounts of energy and releases significant greenhouse gas emissions. Photocatalytic hydrogen production, which relies on sunlight, is a cleaner alternative but faces challenges in maintaining stability under strong light and chemical stress.

To overcome these limitations, the IBS research team introduced a strategy that stabilizes the catalyst within a polymer network while placing the reaction site at the interface between air and water. This setup allows the system to avoid common problems such as catalyst loss, poor gas separation, and reverse reactions. The system breaks down plastics like PET into useful byproducts such as ethylene glycol and terephthalic acid, while releasing clean hydrogen into the air.

“The key was engineering a structure that works not only in theory but also under practical outdoor conditions,” explained Dr. LEE Wanghee, a postdoctoral researcher at MIT and co-first author of the study. “Every detail — from material design to the water-air interface — had to be optimized for real-life usability.”

The researchers demonstrated that their system remained stable for over two months, even in highly alkaline conditions. The floatable catalyst system also works in diverse real-world water environments, including seawater and tap water

In tests using a one-square-meter device placed outdoors under natural sunlight, the system successfully produced hydrogen from dissolved PET bottle waste. Additional economic and scale-up simulations showed that the technology can be expanded to 10 or even 100 square meters, offering a pathway toward cost-effective, carbon-free hydrogen production.

“This research opens a new path where plastic waste becomes a valuable energy source,” said Professor KIM Dae-Hyeong. “It’s a meaningful step that tackles both environmental pollution and clean energy demand.”

Professor HYEON Taeghwan added, “This work is a rare example of a photocatalytic system that functions reliably in the real world — not just the lab. It could become a key stepping stone toward a hydrogen-powered, carbon-neutral society.”

Figure 1. Turning Plastic Waste into Clean Hydrogen with Sunlight
This illustration shows how a newly developed floatable nanocomposite system produces hydrogen gas by using sunlight to break down everyday plastic waste. The sponge-like material floats on water and absorbs sunlight while converting discarded PET bottles and PLA cups into useful byproducts like ethylene glycol, terephthalic acid, and lactic acid. At the same time, it releases clean hydrogen gas into the air. This simple yet powerful process demonstrates a sustainable and scalable way to upcycle plastic waste into renewable energy using only natural sunlight and water.

Figure 2. Real-World Hydrogen Production from Plastic Waste Using Solar Energy
This figure shows how a one-square-meter outdoor system can turn plastic waste into hydrogen using sunlight.
(a) displays the actual setup of the steel reactor, where a sponge-like catalyst material (Pt-DSA/TiO₂ nanocomposites) floats in a plastic waste solution. Key components such as the nitrogen gas line, gear pump, and gas chromatograph used to measure hydrogen are also shown.
(b) provides a top-down schematic view of the reactor, which includes four quartz windows that let sunlight in.
(c) tracks the system’s performance over two separate days, showing a steady rise in hydrogen production (green) as sunlight intensity (orange) increases throughout the day. Even with natural temperature changes (blue), the system maintained high efficiency, proving it can reliably produce hydrogen from waste in outdoor conditions.