Synthesis of BixOyIz from molecular precursor and selective photoreduction of CO2 into CO

• BixOyIz have been synthesized via processing molecular precursor.
• Bi4O5I2 showed much higher photocatalytic activity than Bi5O7I for CO2 reduction.
• CB-dependent photocatalytic activity of BixOyIz photocatalysts was found.

In this paper, different BixOyIz photocatalysts (Bi4O5I2 and Bi5O7I) have been successfully synthesized via two different methods to process molecular precursor. The precursor was papered by solvothermal method with Bi(NO3)3·5H2O, glycerol and iodine. Bi4O5I2 was obtained by hydrolyzing the precursor, and Bi5O7I was achieved via calcining the precursor at 400 °C. The as-prepared BixOyIz photocatalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and UV–vis diffuse reflectance spectra (DRS). The photocatalytic results showed that Bi4O5I2 and Bi5O7I can photoreduce CO2 into CO selectively. Bi4O5I2 (19.82 umol h−1 g−1) has higher photocatalytic activity for CO2 photoreduction than Bi5O7I (1.73 umol h−1 g−1). The AQY for the solar fuels productions over Bi4O5I2 reached 0.37% at 420 nm monochromatic light irradiation. The selectivity of Bi4O5I2 was more than 99.9%. Photocatalytic mechanism studies revealed that the higher conduction band (CB) edge of Bi4O5I2 resulted in higher photoactivity for CO2 photoreduction.

It is the first report for synthesizing Bi4O5I2 and Bi5O7I ultrathin nanosheets with non-hydrothermal methods. Furthermore, it was found the selective photoreduction of CO2 into CO.Figure optionsDownload as PowerPoint slide