Nonmetal plasmonic TiN nanoparticles significantly boost photoelectrochemical performance for hydrogen evolution of CdS nanoroad array photoanode

Abstract We report for the first time that nonmetal plasmonic TiN nanoparticles act as hot-electron booster to remarkably enhance photocurrent and hydrogen production of CdS nanoroad arrays (NRAs) via a photoelectrochemical cell. The optimized TiN–CdS NRAs produce a bias-free photocurrent of 2.9 mA cm−2. Furthermore, the highest photoconversion efficiency of the TiN–CdS nanorod array (NRA) photoanode with optimized loading of the TiN NPs is up to 2.2%, 1.6-fold that of the pristine CdS NRA photoanode (1.4%) at 0.22 V versus RHE. Most importantly, TiN–CdS NRAs achieve a hydrogen production rate of 101.5 μmol h−1 cm−2, about 2 times higher than that of the CdS NRAs. Experimental evidences of the photoluminescence emission apparently confirm that hot-electron injection from TiN to CdS plays a crucial role for enhancing photocurrent and hydrogen production. This work demonstrates that nonmetal plasmonic TiN can be integrated into new platforms for efficient solar energy conversion.