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journal article·2026-06Open access

Influence of metal precursors on the structure, morphology, and performance of CuO nanorods gas-sensing

Gleison Neres Marques, Amanda Akemy Komorizono, Roberta Yonara N. Reis, Davi Souza Ferreira, Ailton José Moreira, Valmor Roberto Mastelaro, Maria Inês Basso Bernardi, Lucia Helena Mascaro

Applied Physics A· Volume 132· Issue 6
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Abstract

Abstract CuO was synthesized using various metal precursors as Cu 2+ sources via a combined coprecipitation and microwave-assisted hydrothermal method, and its gas-sensing performance was systematically evaluated in relation to its structural, electronic, and morphological properties. This study systematically investigates the role of precursor chemistry as a key parameter in controlling the nucleation and growth of CuO nanostructures under identical synthesis conditions. X-ray diffraction (XRD) confirmed the formation of monoclinic CuO, and the crystallite sizes calculated using the Williamson–Hall method decreased in the order CuO-Chloride > CuO-Nitrate > CuO-Sulfate. Scanning and transmission electron microscopy (SEM and TEM) analyses revealed that all samples were composed mainly of CuO nanorods, with slight differences in thickness and dimensions. The Cu 2+ oxidation state was further confirmed by X-ray photoelectron spectroscopy (XPS). The three sensors exhibited excellent NO 2 detection at 200 °C, with the CuO-N sensor showing the highest response. The limit of detection (LOD) for CuO-N was 0.12 ppm, well below the safety threshold of 1 ppm, demonstrating its capability to detect low NO 2 concentrations. Furthermore, the CuO-N sensor maintained stable responses over four consecutive cycles of 1 ppm NO 2 , indicating good operational stability without degradation of its sensing performance. The sensor produced using a metallic nitrate precursor showed the best NO 2 detection response (58% at 200 °C) at a low NO 2 concentration (1 ppm). These findings highlight the critical influence of precursor selection on the structural and functional properties of CuO nanostructures and demonstrate a general strategy that can be extended to other metal oxide semiconductors for the rational design of high-performance gas sensors.
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NanomaterialsElectronic materials

OpenAlex topics: Copper-based nanomaterials and applications · Gas Sensing Nanomaterials and Sensors · Transition Metal Oxide Nanomaterials

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