Designing one-dimensional hierarchical Cu@Cu2O/CuO core-shell heterostructure for highly sensitive detection of NO2 at room temperature

Developing high-performance room temperature (RT) gas sensors based on conventional metal oxides with simple method is attractive and significant. Herein, we reported a one-pot wet-etching self-assembly strategy to synthesize one-dimensional (1D) hierarchical Cu@Cu2O/CuO nanocomposites with low-temperature and applied it for highly sensitive detection of NO2 gas. Intriguingly, the core-shell heterostructure was longitudinally synchronously formed via in-situ self-assembly of Cu2O/CuO nanosheets and wrapped Cu nanowires (NWs). The as-prepared sensor showed high response to 10 ppm NO2 gas of ∼62.1 within 30 s, excellent selectivity and fast response speed at RT (25 °C). As a vital external factor, humidity has been systematically investigated for its influence on the performance of the Cu@Cu2O/CuO sensor. Notably, the results showed that the moisture air can enhance the sensor’s response and accelerate the recovery process. The response value has been boosted ∼70 times and the recovery time was reduced from 552 s to 14 s by introducing moisture air at the specific sensing stage. These findings provided important reference for the development and application of RT gas sensors. Specially, the facile synthesis strategy showed a good idea for the preparation of high efficiency, low cost and heterostructured sensing materials.