High-Performance Nitrate Photoreduction to Ammonia on Organic Photovoltaic Heterojunction Nanoparticles.

Photocatalytic nitrate reduction to ammonia (NO3RR) could alleviate the energy/environmental burdens associated with Haber-Bosch process, however, still suffers from insufficient visible-light utilization and low ammonia production rate. Herein, we present the first case of photocatalytic NO3RR using a platinum-loaded organic photovoltaic heterojunction nanoparticle (OPV-NP) as photocatalysts. The donor/acceptor interpenetrating network inner OPV-NPs overcomes the limitation of intrinsically short exciton diffusion length of organic photosensitizers. By delicately tuning the chemical/topological structure of near-infrared acceptors, the intermolecular packing strength and crystalline ordering are improved greatly, thus driving the more efficient generation/transport of charge carriers and ammonia production. As a result, the optimized OPV-NPs achieves a first-class photocatalytic ammonia production rate of 6.79 mmol g-1 h-1 and excellent operational stability during 40 h continuous photocatalysis under AM 1.5G simulated sunlight. This work not only highlights the considerable potential of OPV-NPs in photocatalytic NO3RR but also provides valuable insights for rational material design in such a promising photocatalytic system.