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

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.