High performing p-n system of CaFe2O4 coupled ZnO for synergetic degradation of Rhodamine B with white-light photocatalysis and bactericidal action

Abstract

Background

Environmental pollution demands the fabrication of suitable nano-photocatalyst that works under white-light irradiation. The effective interfacial engineering is required for better separation of charges.

Method

Here, the novel magnetic CaFe₂O₄-ZnO nanophotocatalyst was synthesized by adopting a sonochemical method. The CaFe₂O₄-ZnO was analyzed using HRTEM, XRD, FTIR, BET, UV-visible DRS, BET, EIS, and photoluminescence analysis. The photocatalytic performance of CaFe₂O₄-ZnO is evaluated by decolourization of Rhodamine B (RhB). Further, the particles’ multifunctionality was evaluated by testing its antibacterial activity against Bacillus subtilis and Escherichia coli under dark and light.

Significant findings

Here, 97.5% of RhB (25 mg/L) was degraded by CaFe₂O₄-ZnO (60 mg/L) under visible light. The kinetic rate of photocatalysis by CaFe₂O₄-ZnO was 0.027 min⁻¹ which was 13.5 and 9 folds higher relative to pristine CaFe₂O₄ and ZnO. At pH 9, the RhB displayed higher photodegradation. Trapping experiments indicate ·OH radical severe a key role in RhB degradation. The formation of p-n interface boosted better charge separation and improved ROS generation. At 50 mg/L CaFe₂O₄-ZnO, the antibacterial performance under light was 98% against B. subtilis and 99.9% against E. coli. The present study reports CaFe₂O₄-ZnO nanophotocatalyst for the effective environmental remediation through photocatalysis and as an antibacterial agent.