Cooperative effects of surface plasmon resonance and type-II band alignment to significantly boost photoelectrochemical H2 generation of TiO2/CdS/TiN nanorod array photoanode

Abstract

Here, we demonstrate for the first time a novel ternary TiO2/CdS/TiN nanorod array (NRA) photoanode for high-efficiency photoelectrochemical H2 generation under bias-free simulated sunlight illumination. The ternary photoanode was constructed through modifying TiO2 nanorod arrays with two-dimensional (2D) CdS nanosheets and nonmetal plasmonic TiN nanoparticles. In this novel photoanode, 2D CdS nanosheets with large surface area not only improve visible light absorption, but also extend the contact area with TiO2 to form type-II band structure favorable for the separation and transfer of photogenerated electron-hole pairs. Moreover, 2D CdS nanosheets provide more sites to absorb TiN nanoparticles to further boost photon energy utilization via surface plasmon resonance-induced hot electron injection. The TiO2/CdS/TiN NRA photoanode achieved an average H2 generation rate of 129.6 μmol cm−2 h−1, 4.2 times that of TiO2 NRA photoanode. Substantially boosted photoelectrochemical H2 generation of the TiO2/CdS/TiN NRA photoanode is attributed to effective hot-electron injection and charge separation.