Fabrication of Novel n-n Heterojunction Bi2O2CO3/AgVO3 Photocatalytic Materials with Visible-Light-Driven Photocatalytic Activity Enhancement.

This research successfully synthesized a novel n-n heterojunction Bi2O2CO3/AgVO3 nanocomposite photocatalyst via the in situ chemical deposition process. Characterization results strongly confirmed the formation of a tight heterojunction at the Bi2O2CO3/AgVO3 interface. The nanocomposite exhibited characteristic XRD peaks and FT-IR vibrational modes of both Bi2O2CO3 and AgVO3 simultaneously. Electron microscopy images revealed AgVO3 nanorods tightly and uniformly loaded onto the surface of Bi2O2CO3 nanosheets. Compared to the single-component Bi2O2CO3, the composite photocatalyst exhibited a red shift in its optical absorption edge to the visible region (515 nm) and a decrease in bandgap energy to 2.382 eV. Photoluminescence (PL) spectra demonstrated the lowest fluorescence intensity for the nanocomposite, indicating that the recombination of photogenerated electron-hole pairs was suppressed. After 90 min of visible-light irradiation, the degradation efficiency of Bi2O2CO3/AgVO3 toward methylene blue (MB) reached up to 99.55%, with photodegradation rates 2.51 and 2.79 times higher than those of Bi2O2CO3 and AgVO3, respectively. Furthermore, the nanocomposite exhibited excellent cycling stability and reusability. MB degradation was gradually enhanced with increasing the photocatalyst dosage and decreasing initial MB concentration. Radical trapping experiments and absorption spectroscopy of the MB solution revealed that reactive species h+ and ·O2- could destroy and decompose the chromophore groups of MB molecules effectively. The possible mechanism for enhancing photocatalytic performance was suggested, elucidating the crucial roles of charge carrier transfer and active species generation.