Green and ultrafast preparation of layered CuO nanoparticles and its ultrahigh-performance ethanol sensing application

Abstract

Accurately controlling and rapidly fabricating ultra-sensitive micro/nano-scale CuO sensors without the assistance of any assembly template or organic solvent was a major challenge recently. In this work, a flower-like Cu3(PO4)2 precursor was prepared within 10 s by an ultrasonic spray method, and then the precursor was soaked in 80 °C NaOH solutions to rapidly prepare CuO material with different microscopic morphologies. Through testing the sensing performance of CuO products for 400 ppm ethanol, it was found that the highest sensitivity of CuO nanoparticles prepared by this method reached 135 (response/recovery time was 173 s/118 s respectively), which was much higher than CuO nanorods and CuO nanosheets, and the sensitivity for 10 ppm ethanol reached 19.9, indicating that the product had an ultra-high sensitivity and an ultra-low detecting limit. At the same time, the optimal detecting temperature has been reduced to 225 °C, while still retaining excellent selectivity, reproducibility, and stability. Furthermore, the whole process only took several minutes, instead of several-day reacting process in the previous work. It provided a way for the rapid fabrication of ultra-sensitive CuO sensor in a green strategy.