Synthesis of one-dimensional Bi2O2CO3–Bi(OHC2O4)·2H2O heterojunctions with excellent adsorptive and photocatalytic performance

Abstract

A one-dimensional (1D) Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O heterostructure was synthesized by a low temperature solution method using Bi(OHC₂O₄)·2H₂O nanorods as templates. Bi₂O₂CO₃ nanosheets vertically grew onto the Bi(OHC₂O₄)·2H₂O rods along the long axial direction. Its adsorption capacity for organic pollutants was evaluated using methyl orange (MO) as a model. The results showed that the Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O heterostructure had an excellent adsorption capacity of 95.78 mg g⁻¹ and repeatability for MO. The Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O heterostructure also possessed excellent photocatalytic activity to degrade dyes (MO, RhB and MB) under solar/UV light irradiation. 20 mg L⁻¹ of RhB, 30 mg L⁻¹ of MB and 75 mg L⁻¹ of MO could be completely degraded by the Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O photocatalyst in 15, 25 and 120 min, respectively. This superior adsorptive and photocatalytic performance is ascribed to the synergistic effect of the big BET surface area and the formation of a number of junctions in the Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O heterostructure. A trapping experiment of the active species during the photocatalytic degradation was carried out, and the result indicates that the O₂⁻˙ radical and h⁺˙ play a major role in the photocatalytic degradation process. This study provides a general and effective method to fabricate a unique 1D Bi₂O₂CO₃–Bi(OHC₂O₄)·2H₂O heterostructure with both photocatalytic and adsorptive performance on a large scale.