Ag Electronic Sensitization on CuO Nanoarrays for CO Detection

In situ grown 3D CuO nanoarray structures with an ordered architecture have emerged as promising materials for advanced CO gas sensing platforms owing to their intimate anchoring on a substrate, large surface area, and abundant exposed active sites. However, 3D CuO nanoarrays encounter high working temperature, slow response time, and inferior response value, impeding their practical use for CO gas detection. Herein, an Ag electronic sensitization strategy is proposed by a facile in situ deposition method. By innovatively constructing Ag nanoparticle coatings on the surface of CuO nanocone arrays, a high response ( R g / R a ) of 4.95 to 100 ppm of CO was achieved at a lower temperature of 180 °C, which is more than three times higher than that of pure CuO (240 °C, R g / R a = 1.53). At the same time, Ag/CuO has a fast response time ( t res ) of 49 s and a recovery time ( t rec ) of 56 s, which is at least 19 s shorter than pure CuO. In addition, the sensor has good CO selectivity for other gases such as CO, NH 3, C 3 H 6 O, and CH 4 O, as well as long-term stability for 8 weeks (relative error 4.03%), which is better than pure CuO (relative error 6.45%). This excellent performance is mainly attributed to the synergistic effect of the unique nanoarray structure of Ag/CuO and the strong sensitization effect of Ag. Therefore, this study provides a novel and promising strategy for developing high-performance chemical sensors using interfacial engineering.