Photocatalytic Transfer Hydrogenation Using Plastic Hydrolysates as Hydrogen Donor

The synthesis of aromatic amines requires harsh conditions or the use of fossil-derived hydrogen (H₂). Here, we address this limitation by demonstrating photocatalytic transfer hydrogenation (PTH) of nitroarenes into anilines employing plastic hydrolysates as electron and proton (hydrogen) donors under ambient temperature and pressure. PTH is achieved using a cobalt-promoted molybdenum sulfide (^CoMoS₂) electrocatalyst integrated with a carbon nitride (CN_x) semiconductor photocatalyst in acidic aqueous solution. ^CoMoS₂ reduces nitroarenes to anilines at -0.7 V versus RHE with a Faradaic yield of 70% and superior activity to platinum. The ^CoMoS₂-CN_x photocatalyst produces anilines under simulated solar light (AM 1.5 G, 25°C), achieving 83%-99% yield from 24 nitroarenes using 4-methylbenzyl alcohol as a model hydrogen donor. Acid hydrolysis of condensation polymers provides a source of alcoholic monomers in aqueous solution that can be used as a sustainable hydrogen donor for PTH in >80% yield using AM 1.5G or LED (405 nm, 33 mW cm^-2) irradiation. A technoeconomic analysis (TEA) at pilot scale producing 1 t aniline day^{- 1} using polyethylene terephthalate (PET) reveals a cut in cradle-to-gate emissions by ∼77% using PTH with ^CoMoS₂-CN_x compared to conventional Pd/C hydrogenation with H₂ from steam methane reforming (SMR-H₂) and a revenue-generating levelized cost of aniline (LCOA) when co-produced with terephthalic, acetic, and formic acids.