A surface plasmon polariton-triggered Z-scheme for overall water splitting and solely light-induced hydrogen generation

Abstract

We propose an advanced design of a plasmon-triggered Z-scheme for efficient overall water splitting (OWS), performed without the addition of sacrificial agents and by utilizing photons with longer wavelengths (close to NIR). As a Z-scheme, we used WO₃ flakes coupled with CdS quantum dots, which ensured OWS under illumination with shorter wavelengths. As a plasmonic support, a periodical Au grating, able to support surface plasmon polariton excitation under NIR illumination, was used. The efficiency of the proposed structure was tested using photo-electrochemical and solely light-induced OWS. It was demonstrated that plasmon triggering makes the utilization of low-energy photons possible in OWS. The amount of light-produced hydrogen increased synergistically under double-wavelengths (simultaneous Z-scheme triggering and plasmon excitation) or broad light spectrum illumination. Thus, our work shows an effective way to increase the efficiency of the Z-scheme for OWS with the complete utilization of sunlight energy.