BiVO4/PANI composite with p-n heterostructure for enhanced photocatalytic activity towards Cr(VI) reduction. (August 2022) - Wang, Li-Hui
Abstract: A novel p-n heterostructure BiVO4 /polyaniline (BiVO4 /PANI) composite was prepared via a hydrothermal route with a subsequent oxidative polymerization of aniline (ANi) monomer by adjusting the ANi/BiVO4 mass ratio. The structure, morphology, optical and photoelectric properties of the as-prepared materials were determined by various characterization techniques, while their photocatalytic activities for Cr(VI) reduction were evaluated under visible-light illumination. Comparing to the BiVO4, the BiVO4 /PANI composites had a significantly enhanced Cr(VI) photoreduction activity. The optimum BiVO4 /PANI0.25 exhibited a high Cr(VI) reduction activity (99.6% after 120 min) and good cycle stability (95.1% Cr(VI) removal at the 5th cycle), which reduction efficiency was around 17.5 times higher than that of the BiVO4 . The enhanced photocatalytic performance was described to the synergistic effect between PANI and BiVO4 as well as the p-n heterostructure. The conductive PANI as h + transporter and light acceptor produced more photogenerated carriers and provided a fast electron transport path to accelerate the migration of photogenerated e − -h + pairs, and the semiconductor BiVO4 gave the fine structure stability. At the same time, the p-n heterostructure promoted the separation of photogenerated e − -h + pairs. Furthermore, the possible mechanism for Cr(VI) photoreduction was proposed according to the various characterizations and experiment results. Highlights: BiVO4 /PANI composite was synthesized by a subsequent oxidative polymerization of aniline monomer (ANi). The BiVO4 /PANI0.25 showed a remarkable photocatalytic performance for Cr(VI) reduction. Promoting the separation of photogenerated e − -h + pairs due to formation of p-n heterojunction. High stability and recyclability for BiVO4 /PANI materials.