Metal-free Z-scheme 2D/2D VdW heterojunction for high-efficiency and durable photocatalytic H2 production

Abstract

Metal-free material is a kind of promising ideal candidate in application of photocatalytic hydrogen (H2) production for everlasting direct solar-to-fuel conversion, but a longstanding challenge still is how to achieve the continuously high-efficiency and stable H2 production performance. Herein, metal-free 2D/2D carbon nitride/C-doped BN (CN/BCN) Van der Waals (VdW) heterojunctions are fabricated, and the optimal photocatalytic H2 production rate over them reaches up to 3357.1 µmol h−1 g−1 that far exceeds that of single CN (1298.8 µmol h−1 g−1) under the visible light. Meanwhile, the high apparent quantum efficiency (AQE) of 16.3% at 420 nm is achieved surprisingly. Moreover, the metal-free 2D/2D CN/BCN VdW heterojunction exhibits the superior stability because H2 production rate has barely reduction when enduring 15 cycle runs with total 60 h. The boosted H2 production performance arises from the formation of Z-Scheme mechanism that dramatically accelerates interfacial transfer and separation of charge carriers. This work furnishes a demonstration model for the tailor-made design and fabrication of other challenging metal-free 2D/2D VdW heterojunctions applied to catalysis, electronics, optoelectronics, etc.