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

In this paper, different Bi x O y I z photocatalysts (Bi 4 O 5 I 2 and Bi 5 O 7 I) have been successfully synthesized via two different methods to process molecular precursor. The precursor was papered by solvothermal method with Bi(NO 3 ) 3 ·5H 2 O, glycerol and iodine. Bi 4 O 5 I 2 was obtained by hydrolyzing the precursor, and Bi 5 O 7 I was achieved via calcining the precursor at 400 °C. The as-prepared Bi x O y I z 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 Bi 4 O 5 I 2 and Bi 5 O 7 I can photoreduce CO 2 into CO selectively. Bi 4 O 5 I 2 (19.82 umol h −1 g −1 ) has higher photocatalytic activity for CO 2 photoreduction than Bi 5 O 7 I (1.73 umol h −1 g −1 ). The AQY for the solar fuels productions over Bi 4 O 5 I 2 reached 0.37% at 420 nm monochromatic light irradiation. The selectivity of Bi 4 O 5 I 2 was more than 99.9%. Photocatalytic mechanism studies revealed that the higher conduction band (CB) edge of Bi 4 O 5 I 2 resulted in higher photoactivity for CO 2 photoreduction. [ABSTRACT FROM AUTHOR]