Synthesis of CuO nanosheets by hydrothermal method and their H2S gas sensing properties

• Main Authors: Yu-Hsiang Lin, 林有祥
• Other Authors: Yung-Chiun Her
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/79874741270074838435

碩士 === 國立中興大學 === 材料科學與工程學系所 === 102 === We have successfully synthesized one-dimensional CuO nanosheets by using a hydrothermal method and observed their growth mechanism. The CuO nanosheets were adopted to fabricate a simple gas sensor which can be used for detecting low concentration H2S. The precursors used in the hydrothermal process contained NaOH, urea and copper nitrate. The synthesis temperatures ranged from 90 to 180℃, and reaction time was kept at 3 hours. Under the best synthesis condition, the as-synthesized CuO nanosheets have lengths of around 1000 nm, widths ranging from 500 to 800 nm, and thickness of about 50 to 80 nm. Based on the structural evolution of CuO nanosheets during the synthesis process, we can confirm their growth is governed by the Oriented Attachment(OA) mechanism. The as-synthesized CuO nanosheets were identified as a monoclinic crystal structure by XRD and TEM analysis. The gas sensor device fabricated by CuO nanosheets which exhibited excellent responses to low concentration H2S at operating temperatures ranging from room temperature to 300℃. Upon exposure to H2S gas, the currents of CuO nanosheets gas sensors decreased at operating temperatures above 250℃ or at room temperature, while increased at operating temperatures in between 150 to 200℃. At room temperature, CuO nanosheets gas sensor showed a sensitivity of 1.46, a response time of 140s, and a recovery time of 173s, to 2.76ppm H2S gas. Obviously, CuO nanosheet gas sensor can be used to detect low concentration H2S at room temperature.