Enhanced photocatalytic hydrogen evolution from organic semiconductor heterojunction nanoparticles

Photocatalysts formed from a single organic semiconductor typically suffer from inefficient intrinsic charge generation, which leads to low photocatalytic activities. We demonstrate that incorporating a heterojunction between a donor polymer (PTB7-Th) and non-fullerene acceptor (EH-IDTBR) in organic nanoparticles (NPs) can result in hydrogen evolution photocatalysts with greatly enhanced photocatalytic activity. Control of the nanomorphology of these NPs was achieved by varying the stabilizing surfactant employed during NP fabrication, converting it from a core-shell structure to an intermixed donor/acceptor blend and increasing H₂ evolution by an order of magnitude. The resulting photocatalysts display an unprecedentedly high H₂ evolution rate of over 60,000 µmol h^-1 g^-1 under 350 to 800 nm illumination, and external quantum efficiencies over 6% in the region of maximum solar photon flux.