Photoredox-promoted co-production of dihydroisoquinoline and H 2 O 2 over defective Zn 3 In 2 S 6 .

One of the most sustainable and promising approaches for hydrogen peroxide (H 2 O 2 ) production in a low-cost and environment friendly way is photosynthesis, which, however, suffers from poor carrier utilization and low H 2 O 2 productivity. The addition of proton donors such as isopropanol or ethanol can increase H 2 O 2 production, which, unfortunately, will inevitably elevates the entire cost while wastes the oxidizing power of holes (h + ). Herein, the tetrahydroisoquinolines (THIQs) is employed as a distinctive proton donor for the thermodynamically feasible and selective semi-dehydrogenation reaction to highly valuable dihydroisoquinolines (DHIQs), and meanwhile, to couple with and promote H 2 O 2 generation in one photoredox reaction under the photocatalysis by dual-functional Zn 3 In 2 S 6 photocatalyst. To our surprise, the suitably defective Zn 3 In 2 S 6 offers an excellent and near-stoichiometric co-production performance of H 2 O 2 and DHIQs at unprecedentedly high rates of 66.4 and 62.1 mmol h -1 g -1 under visible light (λ ≥ 400 nm), respectively, which outperforms all the previous reports as far as we can find even though sacrificial agents were employed in those reports. Additionally, photocatalytic redox reaction mechanism demonstrate that H 2 O 2 can be generated through multiple pathways, highlighting the synergistic effect among ROS (·O 2 - and 1 O 2 ), h + and proton donor, which has been ignored in previous studies. This article is protected by copyright. All rights reserved.