Car battery acid can be reused to break down plastics and make hydrogen.

Researchers at the University of Cambridge report a lab method that uses spent acid from car batteries and a resilient photocatalyst to break down plastic waste into intermediates and then, under sunlight, produce hydrogen and acetic acid; the catalyst remained active for about 264 hours in tests.

Researchers at the University of Cambridge published a Joule paper describing a new lab method that uses spent acid from car batteries to help break down plastics and generate hydrogen. The team developed a photocatalyst that resists corrosive acid and paired it with a reactor under sunlight. Laboratory tests ran for about 11 days without a significant drop in catalyst performance. The authors framed the process as a way to use one waste stream to help manage another, while noting more work is needed before commercial use. What researchers reported: - The method, called solar-powered acid photoreforming, treats waste plastics with spent battery acid to break them into simpler compounds such as ethylene glycol, and then a photocatalyst exposed to sunlight converts those products into hydrogen and acetic acid. - The research team said their photocatalyst and reactor operated for about 264 hours (11 days) without a significant decline in activity during laboratory tests. - The paper notes that car batteries are roughly 20% to 40% acid by volume and that this acid is typically discarded and neutralized after lead recovery. - The report cites broader context: about 400 million tonnes of plastic are produced each year, with roughly 9% recycled and about 12% incinerated, the latter figures reported by referenced organizations. - The authors described the approach as intended to complement existing recycling methods and said further experiments are needed to check long-term durability and readiness for scaling. Summary: The reported method creates a circular use of two waste streams by using spent battery acid and sunlight to break down plastics and produce hydrogen and acetic acid. Researchers reported stable catalyst performance over multiple days in the lab but said additional testing is required, and the timing for any commercial deployment is undetermined at this time.