Paired solar driven bias-free nitrobenzene and benzylalcohol photoelectrolysis with condensation cascade for imine synthesis Afreen Hooriya Naceruddin, Motiar Rahaman*, Domenico Gioffre, Chen Han, Erwin Reisner* Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom *Corresponding authors:reisner@ch.cam.ac.uk mr820@cam.ac.uk The solar-driven photoelectrochemical reduction of prevalent noxious substances like nitroarenes offers a promising and sustainable approach for synthesizing fine and bulk chemicals with high commercial value. However, achieving selective control of the reduction pathway remains a significant challenge, often resulting in low-value products. In this work, we report a bias-free photoelectrochemical system with an inexpensive Cu x Sn y ‘dark’ cathode for the highly selective reduction of nitroarenes coupled to a BiVO 4 |Pd photoanode for the oxidation of benzylalcohol. By tuning the composition of the Cu x Sn y catalyst, the cathodic reaction pathway can be selectively directed toward the formation of aniline, dimeric products (azoxybenzene, azobenzene), or a controlled mixture of both. Importantly, a phase-switchable reduction strategy enables the direct generation of either liquid-phase aniline or solid-phase azoxybenzene directly on the electrode surface with high conversion efficiency (>70% across 35 examples) and excellent product selectivity, eliminating the need for downstream separation or purification. This system further integrates a condensation cascade between the cathodic reduction product (aniline) and the anodic oxidation product (benzaldehyde) yielding imines, valuable intermediates in pharmaceutical synthesis, with higher economic value than the starting materials. This bias-free stand-alone photoelectrochemical cascade system was then tested outdoors under natural sunlight for 3 days and produced 59.1 mmol aldehyde cm –2 , 17.7 mmol aniline cm -2 and 16.1 mmol imine cm –2 , exhibiting sustained catalytic activity and effectively achieving solar-powered chemical synthesis from low-cost abundant feedstocks.
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