Carbon Quantum Dot/Silver Nanoparticle/Polyoxometalate Composites as Photocatalysts for Overall Water Splitting in Visible Light

Abstract The design of photocatalysts for overall water splitting in visible light remains a huge challenge. Carbon quantum dots (CQDs)/Ag/Ag 3 PW 12 O 40 nanocomposites have high photocatalytic activities for overall water splitting in visible light without electron acceptors or hole scavengers. In the present system, H 2 evolution was performed on Ag particles. O 2 evolution appears to be a result of the oxidation of H 2 O on the valence band of Ag 3 PW 12 O 40 , which is enhanced by promoted electron‐transfer events at hybrid interfaces of the polyoxometalates and CQDs. The synergistic effects of CQDs, Ag, and Ag 3 PW 12 O 40 enable the design of a water‐splitting catalyst with a remarkably improved efficiency (with an active region of λ <650 nm; apparent quantum yield ≈4.9 % at 480 nm) and operational stability.