Effect of SrTiO3 amount and ultrasonic disperse on the thickness of Bi2O3 nanosheets and the photocatalytic performance of the composite α-Bi2O3/SrTiO3

Abstract

Due to the correlation between structure and activity, even the photoelectric performance of simple materials can be improved by designing component structures reasonably. Taking α-Bi2O3/SrTiO3 as an example, this article reports a novel ultrasound assisted synthesis method for adjusting the thickness of α-Bi2O3 nanosheets (NSs) in heterojunctions. The continuous variation from ∼200 to ∼10 nm confirms that the thickness of NSs is limited by the amount of SrTiO3 added, and ultrasonic dispersion before calcination is a key initiative. Systematic tests indicate that the opto-electronic properties of the heterojunctions are highly thickness-dependent. The heterojunction with a thickness of ∼20 nm α-Bi2O3 NSs has a wider light absorption range (>550 nm), higher photocurrent response (52.8 μA cm−2), lower charge transfer resistance, and efficient catalytic ability for organic degradation (0.071 min−1 for 0.1 g·L−1 RhB). Various spectroscopic evidences display that Bi-O-Ti oxygen bridge bonds provides an efficient transport channel for photogenerated carriers. Furthermore, large specific surface area, and the built-in electric field of heterojunctions jointly accelerate the oxidation degree of pollutants. As high as 98.9% (0.1 g·L−1) and 55.9% (0.5 g·L−1) degradation efficiencies in 1 h, importantly, documented that the α-Bi2O3/SrTiO3 heterojunctions was competitive for the dispose of high-concentration [RhB] outlet water.