Mössbauer, optical, magnetic, electrochemical and antibacterial studies of the Ag/Sr_0.85Ag_0.15FeO_3-δ composite

In this study, Ag/Sr_0.85Ag_0.15FeO_3-δ composite was prepared by sol-gel method. The structure, morphology, and surface properties of this composite have been characterized by X-ray diffraction (XRD) combined with Rietveld analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. XRD and TEM results confirm the existence of the perovskite phase of Sr_0.85Ag_0.15FeO_3-δ and Ag nanoparticles. XPS and Mössbauer spectroscopy results indicate the existence of oxygen vacancies (δ) and different oxidation states of Fe ions. The band gap energy (E_g) of this composite is 3.53 eV and lies in the UV region. The magnetic hysteresis loop (M-H) of this composite reveals the existence of an exchange bias effect because of the competition between antiferromagnetic (AFM) and ferromagnetic order (FM). Electrochemical measurements indicated that the Ag/Sr_0.85Ag_0.15FeO_3-δ composite exhibits pseudocapacitive behavior. The present composite showed strong antimicrobial activity to fight both tested Gram-positive and Gram-negative bacteria as well as unicellular and filamentous fungi strains.