Interface-engineered Fe2O3-ZnO nanocomposites with ZnFe2O4 spinel bridges for efficient OER and antimicrobial activity

Efficient and sustainable catalysts for oxygen evolution and antimicrobial applications are important for energy conversion and biomedical technologies. Here we show that interface-engineered Fe2O3-ZnO nanocomposites with ZnFe2O4 bridges are explored as multifunctional applications. Fe2O3 nanoparticles were synthesized via a Bos taurus indicus urine assisted-route and Fe2O3-ZnO (10-20 wt%Fe) composites by solvent-free solid-state reaction. XRD/Rietveld, FTIR/Raman, BET, SEM-EDS and XPS confirmed rhombohedral Fe2O3, wurtzite ZnO and interfacial ZnFe2O4 with modified cation distribution. Fe2O3 showed the best oxygen evolution performance, requiring 142 mV to reach 10 mA/cm2 with a Tafel slope of 85 mV/dec, high electrochemically active surface area and low charge-transfer resistance. Density functional theory on α-Fe2O3 (110) indicated balanced adsorption of *OH, *O and *OOH with *OH → *O as the potential-determining step. Antibacterial assays and anti-inflammatory tests revealed enhanced responses for the composites. This solvent-free strategy yields Fe2O3-ZnO-ZnFe2O4 architectures that couple efficient alkaline OER with antimicrobial and anti-inflammatory activity. Fe2O3-ZnO-ZnFe2O4 hybrid systems exhibit enhanced charge-transfer kinetics and antimicrobial surface properties, making them suitable as multifunctional materials for electrocatalysis and biomedical applications. Here, the authors use a solvent-free strategy to prepare Fe2O3-ZnO-ZnFe2O4 nanocomposites, demonstrating efficient oxygen evolution under alkaline conditions and enhanced antibacterial and anti-inflammatory responses against Gram-negative and Gram-positive bacteria.