Synthesis and characterization of ZnO-TiO₂ binary nanomaterials for the development of electrochemical sensors

Hybrid nanomaterials offer new opportunities for performance enhancement and the synergy that arises from the combination of two or more oxide components, making them indispensable in the development of technological devices. By combining TiO₂ with ZnO, materials with promising structures are obtained due to their excellent chemical stability under different conditions, absence of toxicity, and superior photocatalytic activity in the visible light region. The selection of the optimal method influences the performance characteristics of the desired material, depending on the intended purpose.

In the present paper, ZnO-TiO₂ materials were obtained using zinc acetate and titanium (IV) isopropoxide as the cation sources, and a two-step precipitation process was conducted. The obtained solution was stirred and maintained at a temperature of ~ 60°C until a colloidal precipitate formed, and the separation of the precursor from the supernatant was performed by centrifugation–decantation and washing steps. The prepared nanomaterials were synthesized at 550 °C for 3 h, and their properties were studied in terms of structure, morphology, and wettability capacity. SEM microscopy revealed a porous structure with agglomerated formations and nanometric particles, and EDX analysis confirmed the material's chemical composition and purity at the atomic level. FTIR spectroscopy confirmed the existence of M-O bonds in the structure of the hybrid material, due to the appearance in the spectrum of absorption bands that can be associated with Zn-O and Ti-O. The XRD analysis revealed the coexistence of crystalline phases specific to each component. The materials developed exhibit strong hydrophilicity, demonstrating their potential for designing a wide variety of sensors.

Acknowledgments: This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, project number PN-IV-P2-2.1-TE-2023-0417, within PNCDI IV, and by the Core Program within the National Research Development and Innovation Plan 2022-2027, with the support of MCID, project no. 2307 (µNanoEl).