Heterojunctions of halogen-doped carbon nitride nanosheets and BiOI for sunlight-driven water-splitting

• Author(s) / Creator(s)

  • Kazi Mohammad Alam, Pawan Kumar, Piyush Kar, Ankur Goswami, Ujwal Kumar Thakur, Sheng Zeng, Ehsan Vahidzadeh, Kai Cui, Karthik Shankar

• A fluorine-doped, chlorine-intercalated carbon nitride (CNF-Cl) photocatalyst has been synthesized for simultaneous improvements in light harvesting capability along with suppression of charge recombination in bulk g-C3N4. The formation of heterojunctions of these CNF-Cl nanosheets with low bandgap, earth abundant bismuth oxyiodide (BiOI) was achieved, and the synthesized heterojunctions were tested as active photoanodes in photoelectrochemical water splitting experiments. BiOI/CNF-Cl heterojunctions exhibited extended light harvesting with a band-edge of 680 nm and generated photocurrent densities approaching 1.3 mA cm-2 under AM1.5 G one sun illumination. Scanning Kelvin probe force microscopy (KPFM) under optical bias showed a surface potential of 207 mV for the 50% BiOI/CNF-Cl nanocomposite, while pristine CNF-Cl and BiOI had surface photopotential values of 83 mV and 98 mV respectively, which in turn, provided direct evidence of superior charge separation in the heterojunction blends. Enhanced charge carrier separation and improved light harvesting capability in BiOI/CNF-Cl hybrids were found to be the dominant factors in increased photocurrent, compared to the pristine constituent materials.

• Date created

  2019-10-09

• Subjects / Keywords

  • carbon nitride nanosheets
  • earth abundant semiconductors
  • charge carrier recombination
  • bismuth oxyhalides
  • photophysics
  • semiconductor photocatalyst

• Type of Item

  Article (Published)

• DOI

  https://doi.org/10.7939/r3-8h3r-qd75

• License

  Attribution-NonCommercial 4.0 International