A Direct Z‐Scheme Van Der Waals Heterojunction (WO3·H2O/g‐C3N4) for High Efficient Overall Water Splitting under Visible‐Light

Abstract

Achieving overall water splitting is crucial for the effective application of recycling solar energy. Here, we design and construct a direct Z‐scheme van der Waals heterojunction composed by ultrathin WO3·H2O and g‐C3N4 nanosheets to achieve efficient overall water splitting without adding any sacrificial agents. This WO3·H2O/g‐C3N4 system can efficiently transport the electrons, which leading to a considerable improvement in the photocatalytic performance. Due to the suitable band edge potentials for H2, O2 evolution, and remarkable charge transfer, the direct WO3·H2O/g‐C3N4 Z‐scheme system exhibits prominent photocatalytic activity for both H2 and O2 production under visible‐light illumination, the H2, O2 production rate up to 482 and 232 µmol g−1 h−1 respectively, which is greatly higher than the H2 evolution of g‐C3N4 nanosheets (109 µmol h−1 g−1) and the O2 evolution of WO3·H2O nanosheets (57 µmol h−1 g−1) under the same condition. The measured quantum efficiency of the WO3·H2O/g‐C3N4 heterojunction reaches 6.2% at 420 nm.