Solar-driven conversion of CO2 and plastics into value-added products provides a potential sustainable route towards a circular economy, but their simultaneous conversion in an integrated process is challenging. Here we introduce a versatile photoelectrochemical platform for CO2 conversion that is coupled to the reforming of plastic. The perovskite-based photocathode enables the integration of different CO2-reduction catalysts such as a molecular cobalt porphyrin, a Cu91In9 alloy and formate dehydrogenase enzyme, which produce CO, syngas and formate, respectively. The Cu27Pd73 alloy anode selectively reforms polyethylene terephthalate plastics into glycolate in alkaline solution. The overall single-light-absorber photoelectrochemical system operates with the help of an internal chemical bias and under zero applied voltage. The system performs similarly to bias-free, dual-light absorber tandems and shows about 10‒100-fold higher production rates than those of photocatalytic suspension processes. This finding demonstrates efficient photoelectrochemical CO2-to-fuel production coupled to plastic-to-chemical conversion as a promising and sustainable technology powered by sunlight.
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This work was supported by the Cambridge Trust (HRH The Prince of Wales Commonwealth Scholarship to S.B.), the European Commission for Horizon 2020 Marie Skłodowska-Curie Individual European Fellowships (GAN 839763 to M.R. and GAN 891338 to S.R.-J.), the Cambridge Trusts (Vice-Chancellor’s Award to V.A. and Cambridge Thai Foundation Award to C.P.), the Winton Programme for the Physics of Sustainability and St John’s College (Title A Research Fellowship to V.A.), a European Research Council (ERC) Consolidator Grant “MatEnSAP” (682833, to M.M. and E.R.), an EPSRC Impact Acceleration Account Award (to E.L. and E.R.), the UKRI Cambridge Circular Plastics Centre (CirPlas, EP/S025308/1 to E.R.), the Hermann and Marianne Straniak Stiftung (to E.R.) and the Swiss National Science Foundation (Early Postdoc Fellowship P2EZP2_191791 to E.L.). We also acknowledge use of the Cambridge XPS system, part of the Sir Henry Royce Institute (EPSRC grant EP/P024947/1). We are thankful to H. Greer (University of Cambridge) for assistance with the electron microscopy, C. M. Fernández-Posada (University of Cambridge) for assistance with the XPS, A. R. Oliveira and I. A. C. Pereira (ITQB, Universidade Nova de Lisboa) for a sample of FDH as well as S. Linley and S. Kar (University of Cambridge) for useful feedback on the manuscript.
The authors declare no competing interests.
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Bhattacharjee, S., Rahaman, M., Andrei, V. et al. Photoelectrochemical CO2-to-fuel conversion with simultaneous plastic reforming. Nat. Synth (2023). https://doi.org/10.1038/s44160-022-00196-0