Carbon dots as solid-state electron mediator for BiVO4/CDs/CdS Z-scheme photocatalyst working under visible light

Abstract

Z-scheme photocatalytic system is an efficient way to achieve high efficiency photocatalytic overall water splitting. However, the acquisition of efficient Z-scheme visible-light photocatalysts is still a huge challenge at present due to the inactive visible light-active component and various low-band-gap for semiconductors. Herein, we constructed the BiVO4/CDs/CdS Z-scheme photocatalyst with carbon dots (CDs) as solid-state electron mediator, which exhibits excellent photocatalytic activity and stability for photocatalytic overall water splitting under visible light. The BCC50 (BiVO4/CDs/CdS with the mass ratio of BiVO4/CdS=50%) as photocatalyst shows the best photocatalytic activity with stoichiometric ratio of H2 evolution rate of 1.24μmol/h and O2 evolution rate of about 0.61μmol/h. The enhanced photocatalytic activity of the Z-scheme photocatalyst can be attributed to high efficiencies for separation and transport of photogenerated charge carriers and extended the lifetime of electrons and holes.