This study aims to develop room-temperature gas sensors and measure the sensor’s sensitivity to gases such as NO2. Zinc oxide nanoparticles (ZnO₃ NPs) were synthesized and combined with tungsten oxide nanoparticles (WO₃ NPs) and graphene oxide nanoparticles (GO NPs) at different concentrations (10%), 30%, and 50%. The gas sensor was measured at room temperature when ZnO₃ NPs were combined with GO NPs at a concentration of 50%/50%.

The study was conducted at the University of Baghdad, College of Science for Women, Department of Chemistry and Department of Physics, Iraq, from October 2024 to January 2025. Nanomaterials were synthesized and deposition using spin-coating with different concentrations of ZnO NPs with WO₃ and GO (10%, 30%, and 50%) to evaluate the gas sensor. The structural, morphological, and optical properties of the purified zinc oxide nanoparticles, the ZnO/WO₃ composite, and the ZnO/GO composite were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and ultraviolet-visible spectroscopy.

The most important recommendations which the study has come up with and the average obtained:

1. 1. Preparation of ZnO/metal oxide nanoparticles using different methods such as the Sol-Gel method, and study of their structural, morphological, optical, and electrical properties, measuring the sensor’s sensitivity to different gases, and then comparing the results.
   2. Preparation of ZnO and metal oxide nanoparticles on different substrates.
   3. Studying the effect of the structural, morphological, and optical properties of other metal oxides and composites with ZnO nanoparticles.
   4. Using WO₃ as nanoparticles instead of ZnO, then forming a composite with a metal oxide and studying its sensing properties.