Researchers at the University of Cambridge have developed a sunlight-powered process that uses old car battery acid and plastic waste to produce valuable industrial chemicals used in medicines, dyes, and plastics.

The team converted plastics such as PET bottles, nylon, and polyurethane into chemical feedstocks that helped drive the production of anilines, an important class of industrial compounds. The process avoids the use of fossil fuel-derived hydrogen gas typically required in conventional manufacturing.

Instead, the researchers used sulfuric acid recovered from spent lead-acid batteries to break down discarded plastics into liquid hydrolyzates. These plastic-derived compounds then acted as a source of protons and electrons needed for the chemical reaction.

Using sunlight and a specially designed cobalt molybdenum sulfide catalyst, the team converted nitroarenes into anilines with yields reaching as high as 99 percent.

Plastic waste powers chemistry

Anilines are widely used in the production of pharmaceuticals, dyes, agrochemicals, and advanced materials. Industrial production of these compounds usually depends on hydrogen generated through steam methane reforming, a fossil fuel-intensive process that operates under high temperature and pressure.

The Cambridge team instead used a process known as photocatalytic transfer hydrogenation, or PTH, which transfers hydrogen from one material to another using light energy.

In the new system, post-consumer plastics were first boiled in sulfuric acid for six hours. This broke the solid waste into soluble monomers and alcohols that later served as hydrogen donors in the reaction.

The researchers combined these hydrolyzates with nitroarenes and a two-part catalyst system made from carbon nitride and cobalt molybdenum sulfide, or CoMoS2. Carbon nitride acted as the light absorber, while CoMoS2 drove the selective chemical conversion.

When exposed to simulated sunlight, the catalyst pulled protons and electrons from the plastic-derived molecules and transferred them directly to the nitroarenes, producing anilines without generating separate hydrogen gas.

Sunlight replaces fossil hydrogen

The system converted 24 different nitroarenes into anilines with yields ranging from 83 percent to 99 percent. The researchers said the reaction remained highly selective even in the presence of other functional groups that often interfere with industrial chemical processes.

The team also found that alcohols generated directly from plastic waste delivered yields above 80 percent. The process worked under both simulated sunlight and standard LED lighting conditions.

Beyond the chemistry itself, the researchers estimated the approach could reduce carbon emissions by 77 percent compared to conventional industrial methods.

The work also points toward a potential circular manufacturing model in which waste plastics and spent battery acid are reused to create high-value chemicals instead of becoming environmental pollutants.

Unlike many photocatalytic systems that rely on expensive precious metals, the new approach uses more abundant materials while maintaining efficiency under acidic conditions.

The study was published in Angewandte Chemie International Edition.