Creating triazine units to bridge carbon nitride with titania for enhanced hydrogen evolution performance.

Abstract In this work, a wealth of triazine units was created in carbon nitride through a facile molten salt method to bridge titania and carbon nitride for accelerating charge transportation and enhancing hydrogen production performance. The doping of triazine ring into C3N4 framework results in more exposure of −C=N− and −C≡N bond and forms a homojunction (MCN), which favors photocatalysis by acting as photoresponse and active centers, respectively. Moreover, the triazine units can bridge the hybridized C3N4 and TiO2, forming a stable MCN/TiO2 homo-heterojunction. Attributed to the matched band energy structure of MCN and TiO2 and the structural characteristics of triazine/heptazine heterocyclic, the light response, charge separation and transfer as well as the lifetime of carriers on MCN/TiO2 hybrid are improved significantly. As a result, the MCN/TiO2 homo-heterojunction exhibits excellent activity and stability for photocatalytic hydrogen production performance, up to 2594 μmol∙g-1∙h-1 under simulated solar irradiation, which is 5.5 times higher than that of the bare g-C3N4.