Binary metal oxide nanostructures have received much attention as potential materials in biosensor development, due to their chemical and structural stability, good conductivity, catalytic activity, and high reversible capacity. By combining metal oxides (e.g., TiO₂, In₂O₃, ZnO, and CuO), various versatile materials are obtained, capable of creating sensitive and selective platforms for detecting certain biological or chemical analytes. Among them, In₂O₃-TiO₂ is considered a promising structure for speeding up electron transfer, preventing the recombination of electron–hole pairs, and has superior photocatalytic activity and remarkable photonic activity under visible light illumination.

In this study, the In₂O₃-TiO₂ nanostructures were synthesized by the cation precipitation method, varying the conditions of the synthesis process and thermal treatment at the optimum temperature of 550°C. Different analytical methods were used to evaluate the characteristics regarding the identification of functional groups, determination of the shape and size of the samples, and the purity and crystallinity of the samples. Structural characterization was conducted using FTIR spectroscopy, highlighting bands assigned to In-O and Ti-O bonds; XRD was conducted to find structures of high crystallinity and purity; and EDX provided information at the atomic level. SEM microscopy allowed morphological characterization, finding agglomerated formations of almost-spherical particles of small size. The applicability of the In₂O₃-TiO₂ nanostructures is supported by their hydrophilic behavior and the possibility of percolation, properties determined by contact angle measurements.

Acknowledgments: This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, under 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, under project no. 2307.