In situ sonochemical synthesis of flower-like N-graphyne/BiOCl0.5Br0.5 microspheres for efficient removal of levofloxacin

Abstract

In this work, N-graphyne is in situ coupled with BiOCl_0.5Br_0.5via a facile one-step sonochemical method. To our knowledge, both the synthesis strategy for BiOCl_0.5Br_0.5 and the N-graphyne/BiOCl_0.5Br_0.5 photocatalytic system are new developments. A collection of characterization methods is adopted to detect the morphologies, structures, and electronic and optical properties. The results demonstrate that wrinkle-like N-graphyne nanosheets successfully enwind around or on flower-like BiOCl_0.5Br_0.5 microspheres, which are regularly assembled by BiOCl_0.5Br_0.5 nanosheets. Compared with pristine BiOCl_0.5Br_0.5, N-graphyne/BiOCl_0.5Br_0.5 composites exhibit superior adsorption capacity and visible-light-driven photocatalytic degradation of levofloxacin. In particular, the optimal N-graphyne amount for ameliorating the photocatalytic performance of BiOCl_0.5Br_0.5 is ascertained. In addition, the good stable performance for photocatalysis is confirmed by four cycling experiments. The dominant active species is confirmed to be O₂˙⁻ during photodegradation. The improved photocatalytic activity is attributed to the enhanced visible light response and the accelerated transfer/separation of photogenerated carriers by N-graphyne, which are verified using UV–vis absorption spectra, photocurrents, photopotentials, Nyquist plots, and Mott–Schottky curves. This study develops a new perspective for the synthesis and modification of BiOX solid solution, which can be used as an efficient photocatalyst.