Electron transfer via a carbon channel for efficient Z-scheme solar hydrogen production

Abstract

Z-scheme photocatalysis provides a promising solution to photocatalytic solar water splitting, yet restricted by inferior interfacial charge transfer. Here, we demonstrate a Z-scheme composite photocatalyst made of Fe2O3, a carbon layer, and g-C3N4 that can achieve efficient hydrogen generation from solar water decomposition. The success relies on in-situ preparation of core-shell Fe2O3@C structure at the surface of g-C3N4. Carbon as an intermediate layer thus acts as a bridge that significantly accelerates the migration of photogenerated electrons from Fe2O3 conduction band to g-C3N4 valence band. As a result, the highest rate of H2 generation reaches 5.26 mmol h−1g−1. This activity is approximately 33-time greater than that achieved over pristine g-C3N4 and about 4-time larger than that obtained over a Fe2O3/g-C3N4 heterojunction without internal carbon layer. This work explicates the potential insight of the composite and paves a promising way to engineer the charge transfer behavior.