Chemoenzymatic Photoreforming: A Sustainable Approach for Solar-fuel Generation from Plastic Feedstocks

Plastic upcycling through catalytic transformations is an attractive concept to valorise waste. However, the clean and energy-efficient production of high-value products from plastics remains challenging. We introduce chemoenzymatic photoreforming, a new process coupling enzymatic pre-treatment and solar-driven reforming of polyester plastics under mild temperature and pH to produce clean H2 and value-added chemicals. Chemoenzymatic photoreforming demonstrates versatility in upcycling polyester films and nanoplastics to produce H2 at high yields reaching ~103‒104 µmol gsub–1 and activities at >500 µmol gcat–1 h–1. Enzyme-treated plastics were also used for the first time for photocatalytic CO2-to-syngas conversion with a phosphonated cobalt bis(terpyridine) catalyst immobilised on TiO2 nanoparticles (TiO2|CotpyP). Finally, techno-economic analyses reveal that the chemoenzymatic photoreforming approach has the potential to drastically reduce green H2 production costs to levels comparable to market prices of H2 produced from fossil fuels while maintaining low CO2-equivalent emissions.