Biotemplate-assisted synthesis of CuO hierarchical tubes for highly chemiresistive detection of dimethylamine at room temperature

Abstract

The fabrication of low-temperature metal oxide-based sensors with highly sensitive to carcinogenic organic-amines remains challenging. Herein, a biomorphic CuO-5 material was synthesized by simply immersing mulberry twig slices in copper nitrate solution and calcining the precursors in air at 500 ℃. Its multistage tubes are assembled from well-crystallized nanoparticles, and possess uniform mesopores and abundant oxygen vacancies. These microstructural factors facilitate the rapid diffusion of gas molecules to sensing layer, and improve the conductivity of CuO material, as well as the content of active sites and surface adsorbed oxygen species. In particular, under the synergy of adsorption and catalysis of the suspended bonds for surface Cu2+ ions, this material achieves the high sensing and selective detection of trace dimethylamine (DMA) at room temperature for the first time. At 25 °C, CuO-5 sensor reaches a response value of 35.9–50 ppm DMA, which is 8.3 times larger than that of template-free CuO-0 sample. Meanwhile, the sensor also has good response-recovery reproducibility, low detection limit, and satisfactory moisture resistance and stability. In addition, the mechanism for enhanced sensing of DMA at room temperature is discussed in detail.