TiN Bridged All‐Solid Z‐Scheme CNNS/TiN/TiO2−x Heterojunction by a Facile In Situ Reduction Strategy for Enhanced Photocatalytic Hydrogen Evolution

Abstract

AbstractProper interfacial electron mediators greatly influence the charge transfer efficiency of Z‐scheme photocatalytic system. TiN bridged all‐solid Z‐scheme CNNS/TiN/TiO2−x heterojunction composites are prepared by a facile in situ reduction strategy for highly promoted photocatalytic hydrogen evolution driven by visible light. The reduction process not only creates oxygen vacancies in TiO2 but also reduces partial TiO2 to TiN. Oxygen defected TiO2−x permits TiO2 visible light absorption capacity. Fermi level equilibrium forms internal electric fields at the interfaces to drive the charge transfer. Meanwhile, TiN electrons mediator connects the conduction band of TiO2−x and the valance band of CNNS, which is advantageous for the transfer of photoelectrons from the conduction band of TiO2−x to the valance band of CNNS. Compared with pure carbon nitride (CN), TiO2, and even composites CN/TiO2 without TiN, CNNS/TiN/TiO2−x shows a remarkably enhanced visible light catalytic hydrogen evolution performance of 1230 μmol g−1 h−1, about 95 times than that of pure CN. The dramatically boosted photocatalytic activity is attributed to the extra visible light absorption capacity of TiO2−x and convenient electron transfer between CNNS and TiO2−x through TiN electrons mediator.