Applications for rapid formaldehyde nanoreactor with hierarchical and spherical structure

Cu@SnO2 spherical nanoreactor with hierarchical structure was prepared through a simple solvothermal method, the structure and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) showing the materials with extraordinary 3D nanoarchitectures. The gas sensing properties of the as-prepared pure SnO2 and Cu-doped SnO2 were tested toward various gases. The results showed that Cu-doped SnO2 sensor displayed an excellent selectivity toward formaldehyde at the operating temperature 230 °C, which was much lower than most formaldehyde sensor in heater type among previous reports. The τrec and the τrec values of the Cu-doped SnO2 to 1000 ppm formaldehyde were 2 s and 2 s, respectively, demonstrating extraordinary gas sensing properties, while those of the pure SnO2 sensor were relatively long. The enhancement might be attributed to increased oxygen vacancy due to formation of active centers around doped elements and broad surface of unique mesoporous structure.