Holmium Doped ZnCo2O4@CNTs: Dual Function Nanostructures for Photocatalytic Degradation of Mixture of Dyes and Antibacterial Performance

Abstract

This work successfully presents a solvent-free approach to synthesize zinc cobaltite (ZnCo₂O₄), and holmium-doped zinc cobaltite (Ho–ZnCo₂O₄), and further uses them to prepare nanostructures with carbon nanotubes via ultrasonication (Ho–ZnCo₂O₄/CNTs). As water pollution and energy constraints have become global concerns, there is a continuous need to develop more effective catalytic materials. The XRD patterns confirmed the fabrication and presented a slight backward shifting with greater crystallite size. FTIR profile affirmed the functional groups found in ZnCo₂O₄ and Ho–ZnCo₂O₄. Moreover, the optical spectra showed a bathochromic shift and a reduced bandgap energy (Eg) on the introduction of Ho in the pristine ZnCo₂O₄. The electrochemical impedance spectroscopy (EIS) results showed lower resistances in the case of Ho–ZnCo₂O₄ compared to ZnCo₂O₄, confirming better performance. The materials were further utilized to investigate the photocatalytic efficiency by preparing the mixture of various dyes under Xenon radiations. After 70 min, the Ho–ZnCo₂O₄/CNTs presented 87.69% degradation which was maximum than other catalysts. Furthermore, the materials were utilized to determine their antibacterial activity and results presented that Ho–ZnCo₂O₄/CNTs could not perform actively than others due to the selective inhibitory action against Staphylococcus aureus (S.A) and Klebsiella pneumoniae (K.P).