Controlled synthesis of Bi2O2CO3 nanorods with enhanced photocatalytic performance

Abstract

Bi₂O₂CO₃ nanorods are for the first time synthesized successfully via a solid–gas high temperature method. CO₂ gas in our synthesis first replaces Na₂CO₃ or urea which is usually used to synthesize Bi₂O₂CO₃ in previous literature reports, and bismuth oxalate was used as the bismuth source and template. The optimum synthesis conditions of Bi₂O₂CO₃ nanorods can be obtained by controlling the CO₂ gas flow, the reaction temperature and the calcination time. The Bi₂O₂CO₃ nanorods exhibit excellent photocatalytic activity, and their rate constant for degrading salicylic acid (SA) is 6 times that of Bi₂O₂CO₃ nanosheets. This strengthened photocatalytic activity is attributed to their wider absorbance range, narrower facet band gap and up-shift VB potentials compared to those of Bi₂O₂CO₃ nanosheets. The photoluminescence (PL) spectra and the electrochemical impedance indicate that the Bi₂O₂CO₃ nanorods exhibit high separation efficiency and charge transfer efficiency of photogenerated electron–hole pairs.