Efficient hydrogen evolution and aromatic bromination over Pt/ FAPbBr 3 photocatalytic system

Abstract Photocatalytic hydrogen production from hydrogen bromide (HBr) typically relies on sacrificial hole scavengers such as hypophosphorous acid (H 3 PO 2 ), wasting oxidative potential and suffering from sluggish kinetics. Meanwhile, conventional aromatic bromination utilizes hazardous reagents with low atom economy. Here, we report a synergistic photocatalytic system coupling HBr splitting with aromatic ether bromination over a Pt/formamidinium lead bromide (Pt/FAPbBr 3 ) composite catalyst. Using m‐dimethoxybenzene as a model substrate, the system achieves a hydrogen evolution rate of 398 μmol h −1 (per 200 mg catalyst)—four times higher than the conventional H 3 PO 2 ‐based system. Simultaneously, the brominated product is obtained with >99% selectivity and 98% conversion. Under visible light excitation, Pt/FAPbBr 3 generates charge carriers to drive concurrent H 2 evolution and in situ Br 2 formation; the acid polarizes Br 2 , enabling selective bromination of electron‐rich aromatics. This integrated strategy maximizes solar energy utilization and establishes a new paradigm for coupled solar‐to‐hydrogen conversion and green chemical synthesis.