Synergistic effect of rGO decoration on ZnFe2O4 nanorods for low concentration detection of ammonia at room temperature with high selectivity and response

Abstract

This study introduces an improved sensor for detecting ammonia (NH₃) gas using Zinc Ferrite (ZF) decorated with reduced graphene oxide (rGO) films, prepared through spray pyrolysis and spin coating methods. NH₃, a major pollutant in fertilizer production, poses significant health and environmental risks even at low concentrations. Therefore, detecting NH₃ below exposure limits (25 ppm) is crucial for protecting ecosystems and human health. The prepared optimal rGO concentration and ZF (ZFG1.5) sensor exhibit excellent NH₃ response (45) towards 1 ppm, which is sevenfold better than the ZF film without rGO decoration. This enhancement is attributed to the ZF nanorods on the surface of the rGO, establishing a firm surface interaction with the ZF. This configuration accelerates electron transfer and promotes the adsorption/desorption of gas molecules, further contributing to the improved gas-solid interaction. Besides, the sensor demonstrated excellent repeatability (1.15 %), long-term stability, and high humidity tolerance (coefficient of variation 1.48 %). Additionally, the ZFG1.5 sensor showed a distinct selectivity for NH₃ in a mixed gas environment. The ZFG1.5 sensor is promising for real-time NH₃ monitoring below exposure limits, making it a valuable tool for environmental and health safety.