Datensatz

Zusammenfassung

Heptazine-based carbon nitrides are a class of transition metal free semiconductors, which are extensively studied in various photocatalytic processes. The localized nature of the excitons, incomplete exciton conversion into the charge-separated state and the recombination of the charge carriers are the factors that limit performance of the pristine heptazine-based carbon nitrides. Herein, we design heterojunctions composed of poly(triazine imide) intercalated by LiCl and poly(heptazine imide) phases. The donor-acceptor character of the heterojunctions improves the charge separation yield. The heterojunction with the optimal composition of the phases shows an apparent quantum yield of H₂O₂ formation of 14% at 365 nm and 7% at 465 nm, while the H₂O₂ production rate reaches 7.8mol L⁻¹ gphotocatalyst^-1h^-1 (39 mmol L^-1h^-1 produced by 5 mg of photocatalyst) in batch and 15.9 mol kg_{photocatalyst}^-1h^-1 in flow using a packed-bed photoreactor. The heterojunction undergoes photocharging under anaerobic conditions. The charges stored in the material after irradiation enable O₂ reduction to H₂O₂ in the dark with the rate 367 µmol g_{photocatalyst}^-1h^-1 (1.8 µmol h⁻¹ stored in 5 mg of photocatalyst).