Dual-action nano-agents: Optimizing Mn:Zn co-doped synergy in nickel oxide for rapid photocatalytic dye...

Developing multifunctional materials for combating bacterial contamination and water pollution is crucial for environmental protection and public health. This study presents the successful synthesis of Mn:Zn co-doped NiO nanopowders via the sol-gel method, demonstrating exceptional antibacterial activity and photocatalytic performance. Structural analysis via X-ray diffraction (XRD) confirmed reduced crystallite size from 30 ± 2 nm (pure NiO) to 20 ± 1 nm at 25 wt.% doping. Transmission electron microscopy (TEM) revealed lattice distortions and dopant clustering. Fourier-transform infrared (FT-IR) spectroscopy confirmed dopant incorporation and vibrational changes. UV-visible absorbance spectroscopy and Tauc plot analysis indicated an optimal bandgap reduction to 1.75 eV at 25 wt.% doping, enabling 96.92 % degradation of the Orange II dye within 20 min under visible light. Antibacterial testing showed significant efficacy, with 25 wt.% Mn:Zn/NiO achieving maximum inhibition zones of 12 ± 0.54 mm for Bacillus and 12 ± 0.16 mm for E. coli. The materials' enhanced photocatalytic and antibacterial properties underscore their potential for environmental remediation and microbial control applications. These promising results suggest that the Mn:Zn/NiO composite could serve as a viable candidate for developing advanced materials aimed at tackling pollution and infectious agents. Future investigations will focus on further optimizing the synthesis process and on exploring the long-term stability of these materials in real-world conditions.