Resistive and electrochemical sensing of cu2+ and bi3+ ion in aqueous solution using ni2o3 and its metal-doped nanostructure

Abstract

Heavy metal ion detection is necessary due to the detrimental effects these pollutants can have on the environment and human health. Cu2+ and Bi3+ ions, in particular, are known to pose serious risks when present in elevated concentrations in water sources. They can contaminate drinking water supplies, accumulate in ecosystems, and have toxic effects on aquatic life. Therefore, the development of sensitive and reliable sensing platforms for their detection is crucial for effective monitoring, ensuring water safety, and implementing appropriate remediation strategies. This thesis focuses on the detection and analysis of specific heavy metal ions, namely Cu2+ and Bi3+, in water samples. The material of choice for this study is Ni2O3, which exhibits favourable properties for sensing applications. To enhance its sensing capabilities, Cu and Fe doping were employed on Ni2O3. The synthesized materials were characterized using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). XRD analysis provided insights into the crystal structure and phase composition of the materials, while FESEM imaging allowed for the examination of their morphological features and surface characteristics. Following characterization, working electrodes were prepared using Ni2O3, and resistive sensors were fabricated by drop-casting pure Ni2O3 as well as Ni2O3 doped with 5% Fe and Cu2+ ions. These sensors were designed to detect and quantify the presence of Cu2+ and Bi3+ ions in water samples. The performance of the fabricated sensors was evaluated through a series of experiments and measurements. Specifically, electrochemical and resistive sensing techniques were employed. Pure Ni2O3 was utilized for electrochemical sensing of Cu, while resistive sensing was employed for both Cu2+ sensing using Fe-doped Ni2O3 and Bi3+ sensing using Cu-doped Ni2O3. The results of the experiments demonstrated the efficacy of the Ni2O3-based sensors in accurately detecting and quantifying the targeted heavy metal ions. The electrochemical and resistive sensing approaches exhibited promising performance and sensitivity for the detection of Cu2+ and Bi3+ ions in water samples.