Charge transport channel and nonmetallic plasmon synergistically augment surface reaction kinetics and charge separation for efficient photoelectrochemical hydrogen evolution of CdS/TiN-sensitized Fe2V4O13 photoanode

Abstract

Achieving simultaneous enhancement in the light energy utilization efficiency, bulk charge carrier separation and surface charge carrier injection efficiency as well as the surface reaction kinetics of water oxidation is a formidable challenge for photoanodes in photoelectrochemical (PEC) water splitting hydrogen generation. Herein, nanoparticle-assembled flower-like CdS spheres and nonmetallic plasmonic TiN nanoparticles are exploited to successively sensitize Fe₂V₄O₁₃ nanoporous film (NPF) photoanode for achieving efficient PEC hydrogen evolution. The sensitization of TiN and CdS simultaneously integrates type-II band structure, surface plasmon resonance and Schottky junction into Fe₂V₄O₁₃ NPF photoanode, synergistically achieving simultaneous enhancement in the light energy utilization efficiency, bulk charge carrier separation efficiency, surface reaction kinetics of water oxidation and surface charge carrier injection efficiency. As a result, the highest charge separation and injection efficiencies of CdS/TiN-sensitized Fe₂V₄O₁₃ NPF photoanode are respectively increased by 25.5 and 1.96 times to those of bare Fe₂V₄O₁₃ NPF photoanode. Furthermore, the designed and constructed CdS/TiN-sensitized Fe₂V₄O₁₃ NPF photoanode exhibits substantially boosted unbiased solar-light-driven PEC hydrogen evolution ability with a photocurrent density of 2.12 mA/cm², which is two orders of magnitude (662 times) higher than that of the unsensitized Fe₂V₄O₁₃ NPF photoanode. The findings in this work provide a novel and promising strategy to design and construct high-performance Fe₂V₄O₁₃-based nonmetallic plasmonic photoanodes for potential application in PEC hydrogen evolution.