Fabrication of black phosphorus nanosheets/BiOBr visible light photocatalysts via the co-precipitation method

Abstract

The novel photocatalyst capable of utilizing the full spectrum of solar energy has attracted the attention of researchers. Black phosphorus (BP), as a rising star in an assortment of 2D materials, possesses a broadband absorption due to its tunable direct bandgap, which makes it a candidate photocatalyst. In our work, poly dimethyldiallyl ammonium chloride (PDDA) is used to passivate BP nanosheets (BPNs) to improve its stability. Further, the functionalized BPNs and BiOBr are combined by a one-step co-precipitation method to form nanocomposites. The successful formation of nanocomposites obviously promoted the possibilities for the carrier transporting between BiOBr and BPNs, and effectively hindered the recombination of carriers, which is confirmed by all manner of characterization. Meanwhile, nanocomposites have enhanced light absorption and relatively large specific surface area, which also has a gain in its photocatalytic activity. The as-prepared nanocomposite photocatalysts significantly enhanced the photocatalytic activity with the best degradation effect of 14 and 3.4 times than pure BiOBr towards degradation of methylene orange (MO) and ciprofloxacin (CIP), respectively, under visible light. To get clear proofs of the photocatalytic mechanism, the UV–vis diffuse reflectance spectroscopy, photocurrents, electrochemical impedance spectra and Mott-Schottky measurements et al. were employed and the type-I band alignment was proposed. This finding provides an easily synthesis and effective way of BP/semiconductor photocatalysts and demonstrates a new perspective for designing novel solar light driven photocatalysts.