Construction of novel flower-like functionalized black phosphorus nanosheets/P-doped BiOCl S-scheme photocatalysts with improved photocatalytic activity in RhB and Cr(vi) degradation

Photocatalytic degradation has been developed as a promising strategy for environmental remediation. Black phosphorus (BP) has attracted much attention in the field of photocatalysis due to the adjustable bandgap and high carrier mobility. In this work, we constructed a flower-like BP nanosheet/P-doped BiOCl (BP/P-BiOCl) S-scheme heterostructure via a simple co-precipitation method. The physicochemical properties such as the crystallinity, morphology, chemical environment, and optical and electronic properties of the as-fabricated materials were analyzed by using different analytical techniques. SEM data indicated the successful formation of a flower-like structure of BP/P-BiOCl composites. X-Ray photoelectron spectroscopy data indicated the formation of P-doped BiOCl. X-Ray diffraction and high resolution-TEM data revealed the formation of a hierarchical BP/P-BiOCl heterostructure. The catalytic activity of the as-synthesized samples (15%-BP/P-BiOCl) was tested towards RhB degradation (96% of 20 ppm RhB solution) and Cr(vi) reduction (90% of 20 ppm Cr(vi) solution) under solar light illumination. We demonstrated the formation mechanism of a flower-like structure in which positively charged BPNs assembled with negatively charged P-BiOCl by electrostatic attraction. Furthermore, we revealed the S-scheme photocatalytic mechanism to prove the enhanced photocatalytic activity of BP/P-BiOCl composites. The photodegradation of phenol, radical species trapping experiments and charge transfer route test were performed to prove the formation of the S-scheme. This work provides a facile route for the construction of a flower-like S-scheme heterostructure photocatalyst for efficient solar light photocatalytic performance.