Green synthesis of nickel oxide nanoparticles using Lilium pensylvanicum extract for electrochemical detection of hazardous carbon monoxide gas

This study presents a novel approach to synthesizing nickel oxide (NiO) nanoparticles using an aqueous extract of Lilium pensylvanicum, also known as the Siberian Lily. The primary focus is on the green synthesis of NiO nanoparticles and their application in electrochemical gas sensing for detecting hazardous carbon monoxide (CO) gas. The research highlights the unique phytochemical composition of Lilium pensylvanicum, which provides superior reducing and capping abilities, enabling controlled morphology and defect engineering essential for enhanced gas sensing. The synthesized NiO nanoparticles were characterized using various analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), to determine their structural, optical, and morphological properties. The study demonstrates that the biosynthesized NiO nanoparticles exhibit outstanding CO gas-sensing performance, with a high response value of 445 at 250°C for 100 ppm CO, and fast response and recovery times of 42 seconds and 28 seconds, respectively. The sensor also showed excellent selectivity toward CO over other gases, attributed to its high surface area, oxygen vacancies, and efficient electron transfer. The results confirm the potential of green-synthesized NiO nanoparticles as efficient, selective, and eco-friendly CO gas sensors for environmental and industrial applications. This research bridges a critical gap by introducing a novel, eco-friendly synthesis route and establishing Lilium pensylvanicum-derived NiO nanoparticles as a high-performance candidate for real-time CO monitoring applications.