Construction of a 1D/0D/2D BiFeO3/Ag/g-C3N4 Z-scheme heterojunction for enhanced visible light photocatalysis of methylene blue

Abstract

To improve the utilization of solar energy and the efficiency of photocatalytic organic pollutant degradation, novel Z-scheme heterojunctions with high visible light catalytic performances have been widely developed. Herein, a novel Z-scheme BiFeO₃/Ag/g-C₃N₄ heterojunction with a hierarchical 1D/0D/2D structure and visible light absorption was constructed by matching the suitable band structure between 1D BiFeO₃ and 2D g-C₃N₄ and employing the localized surface plasmon resonance (LSPR) effect of 0D Ag nanoparticles. BiFeO₃ nanofibers were synthesized via the electrospinning technique, providing short electron transport paths and visible light absorption range for g-C₃N₄. Plasmonic Ag nanoparticles were photodeposited on the surface of BiFeO₃ to enhance the separation efficiency of the photogenerated electron–hole pairs between the bulk interfaces. UV-vis DRS, PL, photocurrent and EIS spectra confirmed the important roles of Ag and BiFeO₃ in improving the photocatalytic activity of the Z-scheme heterojunction. The working principle of the BiFeO₃/Ag/g-C₃N₄ Z-scheme heterojunction was proposed, indicating that ˙O₂⁻ and ˙OH are the main active species for the photocatalytic degradation of methylene blue (MB). The prepared BiFeO₃/Ag/g-C₃N₄ heterojunction exhibited the highest photocatalytic activity, where its rate constant was 5.84 times higher than that of the pristine BiFeO₃ and 3.26 times higher than that of the pristine g-C₃N₄. This study offers a new means for the design of novel high-performance photocatalysts, which can be a promising candidate in industrial applications.