Constructing 2D/2D g-C3N4/BiOCl Z-scheme heterojunction for synthesis of imines via photocatalytic coupling of benzylamine

Abstract

Here, 2D/2D Z-scheme heterojunctions, BiOCl/g-C3N4 (CN-B), are successfully prepared for the photocatalytic coupling of benzylamine (BA) to N-benzylidenebenzylamine (NBA) in air atmosphere under visible light. The high conversion (96.1 %) of BA can be achieved over the optimal catalyst (CN-B-1.6), with a selectivity of NBA (95.2 %). The interface charges are redistributed on CN-B because of the strong interaction between BiOCl and g-C3N4, benefiting to the activation of substrates. The results of In situ diffuse reflectance infrared Fourier-transform spectroscopy (in situ DRIFTS), Electron paramagnetic resonance (EPR) and X-ray photoelectron spectra (XPS) reveal that O2 and BA molecules can be activated via coordinating on the interface of CN-B, thus improving the photocatalytic performance. The migrated pathway of photogenerated carriers follows the mechanism of Z-scheme heterojunction, improving the utilization of electrons-holes. Finally, we put forward a possible mechanism at a molecular scale to explain the photocatalytic pathway. This work emphasizes how to create an effective heterojunction photocatalyst for the photocatalytic organic synthesis.