Temperature-Controlled Synthesis of Porous CuO Particles with Different Morphologies for Highly Sensitive Detection of Triethylamine

Because porous metal oxides with controllable morphologies have been attracting much attention for their potential applications in the fields of adsorption/separation, sensing, energy storage, and conversion, it is highly desirable to prepare new morphology of metal oxides and investigate their performance. In this work, CuO particles with different shapes such as octahedron, sponge-like octahedron, and sphere have been synthesized through thermal decomposition of crystalline Cu(II)-organic frameworks (HKUST-1). The structure and morphology of as-prepared CuO particles have been fully characterized by the usage of XRD, XPS, SEM, and TEM. The gas-sensing behaviors of these CuO samples have been investigated and our results show that CuO-400 with spherical shape displays unprecedented high response (maximum value, 102) for triethylamine (TEA) at 100 ppm with a low detection limit of 5 ppm, a lower working temperature (230 °C), excellent reproducibility, and long-term stability. The highly sensing behavior of CuO-400 sphere might be due to its special structural factor with many open active sites for oxygen adsorption, which could react with TEA molecules more efficiently. Our results clearly suggest that porous CuO particles should be promising candidates for future practical application to detect TEA vapor at relatively low temperature.