Rapid and Highly Sensitive of Amperometric Ammonia Sensor Using Green Synthesized CuO Nanoparticles as Anode Material

Abstract

In modern era, air pollution arises from various human activities and natural processes. Several studies have revealed that automobile exhaust monitoring sensors are indispensable tools for ensuring compliance with emissions regulations, protecting public health, reducing environmental impact, optimizing engine performance, and facilitating diagnostic and maintenance activities in the automotive industry. This study introduces a green synthesis of pure CuO using Calotropis giantea (CG) leaf extract. The synthesized CuO with CG leaf extract was characterized through numerous analytical techniques to understand the basic properties of the synthesized material. The novelty of this work lies in the fabrication of the electrode material of CuO based nanoparticles for sensing applications. The Calotropis gigantea leaf extract enhances the surface activity area of CuO and leads to achieving good electrochemical performance. In the amperometric mode, the fabricated sensor device was applied with a constant bias voltage of + 1 V at the CuO nanoparticle–based anode relative to the fixed lanthanum strontium cobaltite La_0.5Sr_0.5CoO₃ (LSC) cathode. Utilizing LaGaO₃ (LSGMN) as the solid electrolyte, this electrochemical device achieved a remarkable sensitivity of 586 μA/decade at 550 °C. The fabricated sensor structure was tested for detecting ammonia (NH₃) concentrations ranging from 3 to 40 ppm in a base gas (mixture of 5% O₂ and N₂), in the temperature range of 300 to 650 °C. This testing configuration was designed for exhaust gas monitoring applications. Notably, the sensor demonstrated a rapid response time of 20 s and a recovery time of 90 s, while detecting ammonia, making it effective for real-time monitoring in various environmental conditions.

Graphical Abstract