Electrostatic Self-Assembled Synthesis of Amorphous/Crystalline g-CN Homo-Junction for Efficient Photocatalytic H Production with Simultaneous Antibiotic Degradation.

g-CN has been regarded as a promising photocatalyst for photo-reforming antibiotics for H production but still suffers from its high charge recombination, which has been proven to be solvable by constructing a g-CN homo-junction. However, those reported methods based on uncontrollable calcination for preparing a g-CN homo-junction are difficult to reproduce. Herein, an amorphous/crystalline g-CN homo-junction (ACN/CCN) was successfully synthesized via the electrostatic self-assembly attachment of negatively charged crystalline g-CN nanorods (CCN) on positively charged amorphous g-CN sheets (ACN). All the ACN/CCN samples displayed much higher photo-reforming of antibiotics for H production ability than that of pristine ACN and CCN. In particular, ACN/CCN-2 with the optimal ratio exhibited the best photocatalytic performance, with a H evolution rate of 162.5 μmol·g·h and simultaneous consecutive ciprofloxacin (CIP) degradation under light irradiation for 4 h. The UV-vis diffuse reflectance spectra (DRS), photoluminescence (PL), and electrochemical results revealed that a homo-junction is formed in ACN/CCN due to the difference in the band arrangement of ACN and CCN, which effectively suppressed the charge recombination and then led to those above significantly enhanced photocatalytic activity. Moreover, H was generated from the water reduction reaction with a photogenerated electron (e), and CIP was degraded via a photogenerated hole (h). ACN/CCN exhibited adequate photostability and reusability for photocatalytic H production with simultaneous CIP degradation. This work provides a new idea for rationally designing and preparing homo-junction photocatalysts to achieve the dual purpose of chemical energy production and environmental treatment.