Room-temperature sensing performance of CuO/Cu2O nanocomposites towards n-butanol

Sensing toxic volatile organic compounds (VOCs) at room temperature is of importance for the future applications in light of safety and energy-saving concerns. In this study, a simple method for preparing the CuO/Cu2O spherical nanocomposites was developed by calcining the pristine Cu2O nanospheres in air at 140 °C for different times. Among the CuO/Cu2O composites, the CuO/Cu2O-2 sample showed the highest sensing response (5.9) and short response/recovery time towards 100-ppm n-butanol at room temperature. This response was two times higher than that of the pristine Cu2O nanospheres (2.8). The enhanced sensing mechanism of CuO/Cu2O-2 was attributed to the several reasons: (1) larger specific area; (2) abundant pores and suitable pore size distribution; (3) the new-formed amorphous CuO with the calcination; and (4) the electron sensitization, which was originated from the band bending caused by the different band structures of CuO and Cu2O. The CuO/Cu2O nanocomposites shed light on promising materials to achieve the room-temperature detection of n-butanol in practical application.