Effect of Bi/Ti ratio on (Na0.5Bi0.5)TiO3/Bi4Ti3O12 heterojunction formation and photocatalytic performance

Bismuth-based metal oxide compounds are promising candidates as novel photocatalysts for environmental remediation. However, their low quantum efficiencies and rapid electron-hole recombination times have hindered their uptake for photocatalytic applications. The present work reports an investigation of the effects of variable Bi/Ti ratio during hydrothermal synthesis on the phase assemblage, nanostructure, surface chemistry, band gap, and photocatalytic performance. Increasing Ti concentration resulted in variations in characteristics and properties according to the sequential formation of the principal phases alpha-Bi2O3 (BO), Bi4Ti3O12 (BTO), and (Na0.5Bi0.5)TiO3 (NBT). Samples fabricated with precursors having a Bi/Ti ratio of 12/12 exhibited the highest methylene blue (MB) photodegradation rate of 92% under UV irradiation for 2 h. This excellent photocatalytic performance is attributed to the formation of an NBT/BTO heterojunction with advantageous band alignment.

Automated summary

This study investigates the effects of different Bi/Ti ratios during hydrothermal synthesis on bismuth-based metal oxide compounds, and finds that samples prepared with a Bi/Ti ratio of 12/12 exhibit the highest methylene blue degradation rate under UV irradiation. This excellent performance is attributed to the advantageous band alignment of the NBT/BTO heterojunction.