Abstract
? 2022Photocatalytic pure water splitting using particulate photocatalyst is usually restricted by the extremely slow reaction kinetics. Herein, we demonstrated a novel Z-scheme heterojunction, composed of a phosphatized p-type gallium indium zinc oxynitride (GIZON-P) and a n-type g-C3N4 (CN). Results show that phosphorization could reduce hole concentration within p-type GIZON, resulting in the transition of Z-scheme band structure into type-Ⅱ style. This transformation leads to a completely changed reaction mechanism, i.e., from a two-electron H2/H2O2 production to a four-electron H2/O2 generation. Although this four-electron pathway is dynamically unfavorable, the rapid charge separation by the type-II band arrangement together with thin InP layer at the surface of GIZON-P could remarkably accelerate the rate-limited O2-evolution process. The phosphatized composite presents an excellent photocatalytic performance, with a H2/O2 rate of 1340/643 μmol h g. The gained quantum yield of 12.6% at 430 nm is among the best results in photocatalytic pure water splitting.
NSTL
Elsevier