Synthesis and visible light catalytic activity of HC/BiOCl/BiOBr microspheres

In this paper, waste peanut shell is used as raw material to produce biochar (HC), which makes reasonable use of agricultural waste and conforms to the concept of low carbon and environmental protection. HC/BiOCl/BiOBr microspheres are synthesized by solvothermal method. The crystal structure, morphology and optical properties of HC/BiOCl/BiOBr were characterized by XRD, SEM, TEM, EDX, XPS, PL and UV-Vis DRS. SEM shows that HC/BiOCl/BiOBr is composed of a spherical structure made of stacked sheets. The prepared HC/BiOCl/BiOBr showed high photocatalytic performance, and the degradation efficiency of RhB was 98.72% after 20 min of sunlight irradiation, which is higher than that of pure BiOCl and BiOBr. PL, EIS, BET and DRS spectra show that HC/BiOCl/BiOBr has low electron hole recombination, high photogenerated carrier separation rate, suitable aperture and strong visible light absorption capacity, which are the main reasons for its good photocatalytic activity. Free radical trapping experiments show that h⁺ plays an important role in photocatalysis. The possible photocatalytic reaction mechanism of RhB degradation by HC/BiOCl/BiOBr was deduced. This study provides a new reference for the design of high performance and environmentally friendly photocatalytic materials.