Encapsulation of tin oxide layers on gold nanoparticles decorated one-dimensional CdS nanoarrays for pure Z-scheme photoanodes towards solar hydrogen evolution

Abstract

Despite their high potential for solar energy conversion into chemical fuels, most artificial all-solid-state Z-scheme photosystems have disordered structures and focus on power photocatalytic water splitting applications rather than photoelectrochemical (PEC) cells. Herein, an innovative pure Z-scheme heterostructure, CdS/Au/SnO2-S, composed of one-dimensional (1D) oriented CdS nanorods modified with SnO2-wrapped Au nanoparticles (NPs), was designed as a photoanode for highly efficient PEC hydrogen evolution. Systematic characterization confirms that the incorporated Au NPs not only act as the host platform to support the SnO2 layer growth but also play a key role as the electron mediator for strengthening the vectorial charge transfer from SnO2 to CdS. This reinforced Z-scheme charge transportation channel is favorable for suppressing the bulk charge recombination process, increasing the overall carrier density, and preserving the strong redox capability, ultimately resulting in a considerably improved photocurrent density and photo-to-current conversion efficiency with better corrosion resistance.