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In this work, nanostructured copper oxide of varied morphologies and high surface area were prepared by calcination of copper oxalate precursors, and were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and differential thermal analysis, and nitrogen adsorption–desorption measurements. The sphere-like CuO (specific surface area: 73 m2 g−1) functionalized QCM resonators were fabricated and explored for HCN sensing. The sensitivity (10 s HCN exposure) of sphere-like CuO functionalized QCM resonators reached as high as 6.53 Hz μg−1. The reproducibility and stability of sphere-like CuO functionalized QCM resonators was excellent, and the selectivity was very high with a converse response to examined common chemicals. The high surface area CuO functionalized QCM sensors may be applicable for HCN gas sensing. [ABSTRACT FROM AUTHOR]

Abstract: In the current work, CuO nanoparticles were synthesized in a facile way, and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetry. Using these CuO nanoparticles, CuO functionalized QCM resonators were fabricated and explored for HCN sensing. The sensing properties were studied by a sensor characterization system coupled with a mass spectrometer. The sensor response to HCN (+347Hz) was found to be in an opposite direction as compared with other common volatile substances (ether: −1230Hz; water: −1815Hz; n-hexane: −2100Hz; benzene: −3410Hz; acetic acid: −4840Hz; ethanol: −6270Hz), offering excellent selectivity for HCN detection. In addition, the sensitivity (15.1Hz/μg) was very high, and the response (30s) and recovery (750s) were very fast. A sensing mechanism was proposed based on experimental results, in which a surface redox reaction occurs between CuO and Cu2O on the nanoparticle reversibly upon contact with HCN and air, respectively. The current results would provide an exciting alternative to fast, sensitive and selective detection of trace HCN, which would be of particular benefit in the area of public security and environmental applications. [Copyright &y& Elsevier]

Copper oxide nanoparticles were prepared by the solvothermal method, and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption measurements. The as-prepared CuO nanoparticles functionalized QCM resonators were fabricated and explored for HCN sensing under varied humidity conditions. When the humidity of air containing HCN is the same as that of environmental air, a characteristic positive frequency shift of CuO nanoparticles functionalized QCM resonator is always observed towards HCN because of a reversible surface redox reaction between CuO and HCN. The sensitivity of CuO nanoparticles functionalized QCM resonators increases with increase of relative humidity in the range of 9-51%. These results provide an important guidance for further developing HCN gas sensors towards practical applications. [ABSTRACT FROM AUTHOR]