Effective light scattering and charge separation in nanodiamond@g-C3N4 for enhanced visible-light hydrogen evolution

Abstract

Development of heterostructured photocatalysts that promotes charge separation of semiconductor materials is crucial towards efficient photocatalytic hydrogen evolution. Here nanodiamond (ND)@graphitic carbon nitride (g-C3N4) nanosheet heterostructures were synthesized via a facile one-step pyrolysis approach. The ND@g-C3N4 heterostructures exhibit enhanced photocatalytic activity for hydrogen evolution from water splitting as compared with pristine g-C3N4. The optimal heterostructures with 10 wt% ND loading content show the best performance in photocatalytic H2 evolution under visible light irradiation, which is more than 5.6 times higher than that of the pristine g-C3N4. The increased light-trapping induced by the scattering of the NDs promotes more localized charge carriers generation, which is clarified by the combined experimental results and finite difference time domain simulations. Meanwhile, the effective charge separation at the ND@g-C3N4 interface due to the energy level matching can synergistically induce the enhanced photocatalytic activity of g-C3N4.