# A New Type of Nitrate Potentiometric Sensor Prepared Using Hybrid Metal Oxide/Metal Nanoparticles

## TL;DR

Researchers developed a new nitrate sensor using metal-doped ZnO nanoparticles, which improved performance and allowed accurate nitrate detection in soil.

## Contribution

The first use of noble metal-doped ZnO nanoparticles as a solid contact in nitrate ion-selective electrodes is introduced.

## Key findings

- Pt-doped ZnO nanoparticles showed the highest electric capacitance and hydrophobicity.
- Metal doping improved electrical capacity and reduced contact angles of ZnO nanoparticles.
- The sensor successfully determined nitrate content in soil samples.

## Abstract

In this study, for the first time, ZnO nanoparticles doped with noble metals (Pt, Ag, Au) were employed as a solid contact in nitrate ion-selective electrodes based on a glassy carbon internal electrode, and their performance was described and studied. Nanoparticles were synthesized by pulsed laser ablation in liquid. They were placed as an intermediate layer between the inner electrode and the ion-selective membrane. The impact of nanoparticle type on electrode performance was assessed by analyzing their analytical and electrical parameters using both potentiometry and electrochemical impedance spectroscopy. It was found that the determined properties of hybrid nanoparticles, as well as their effectiveness as a solid contact, depend significantly on the type of metal doping. Doping ZnO nanoparticles with metals increases their electrical capacity and reduces contact angles. The best results were obtained for the electrode modified with platinum-doped zinc oxide nanoparticles, characterized by the largest electric capacitance and the most hydrophobic properties among the hybrid nanoparticles. This electrode has been successfully used for the potentiometric determination of nitrate content in soil.