Interfacial Co-N bond bridged CoB/g-C3N4 Schottky junction with modulated charge transfer dynamics for highly efficient photocatalytic Staphylococcus aureus inactivation

Abstract

• CoB/CNs Schottky junction with interfacial Co-N bond was prepared; • CoB/CNs presents excellent performance for photocatalytic S. aureus inactivation; • Interfacial Co-N bond can efficiently modulate the charge transfer dynamics; • Two-step single-electron induced O 2 reduction (O 2 → ·O 2 – → H 2 O 2 ) is enhanced. Interfacial engineering plays a critical role in modulating the electron transfer dynamics of photocatalysis, but has been rarely explored. Herein, a novel cobalt boride/graphitic carbon nitride nanosheet (CoB/CNs) Schottky junction with interfacial Co-N bond was successfully prepared to uncover the function of interfacial chemical bond in photocatalytic antibacterial process. Density functional theory (DFT) calculation and experimental investigation demonstrate that the interfacial Co-N bond can act as an electron transfer channel to efficiently steer the electron transfer from CNs to CoB, and then an upward band bending with the height of 0.26 eV is formed in CoB/CNs Schottky junction. The formed upward band bending can rapidly separate the photogenerated electron-hole pairs by preventing electrons from flowing back to the CNs, which causes the surface electron transfer efficiency ( η trans ) to increases from 41.8% (CNs) to 57.7% (CoB/CNs-2). Rotating disk electrode (RDE) results demonstrate that compared with CNs (n = 2.38), the oxygen reduction reaction in CoB/CNs-2 (n = 2.19) is more selective to a two-electron transfer route. Meanwhile, further research on reactive oxygen species reveals that it is an indirect two-step single-electron oxygen reduction process, which is beneficial for the generation of ·O 2 – and H 2 O 2 . As a result, 7 × 10 7 CFU/mL of Staphylococcus aureus ( S. aureus ) can be completely inactivated by CoB/CNs-2 with 125 min under visible light irradiation. It is expected that our work will provide some guidance for the exploitation of more advanced hybrid photocatalysts system through interfacial engineering.