In-situ loading of (BiO)2CO3 on g-C3N4 with promoted solar-driven photocatalytic performance originated from a direct Z-scheme mechanism

The photocatalytic performance of g-C3N4 has been significantly hindered by its inherent drawbacks; therefore it is highly desirable to ameliorate the photocatalytic performance of g-C3N4. Construction of effective direct Z-scheme photocatalysts is facile approach to boost the separation and transfer of charge pairs, remarkably promoting the photocatalytic performance of the catalysts. Herein, (BiO)2CO3/g-C3N4 heterojunctions with improved solar-driven photocatalytic performance were in-situ constructed by loading (BiO)2CO3 onto the surface of g-C3N4 via a hydrothermal route. The (BiO)2CO3/g-C3N4 heterojunctions were optimized by adjusting the molar ratio between two components. The resulting heterojunctions display much higher photocatalytic activities for rhodamine B (RhB) degradation compared to the pristine g-C3N4 and the 1.5% sample exhibits the highest photocatalytic activity. Based on the surface photovoltage spectroscopy (SPS), the enhanced photocatalytic performance of (BiO)2CO3/g-C3N4 catalysts can be definitely assigned to the significantly promoted charge transfer and separation. The results confirm that the photoinduced charge separation of (BiO)2CO3/g-C3N4 composites obeys a direct Z-scheme mechanism, proven by the results of electron spin-resonance (ESR) and band edge potential.