CuO/ZnO hollow nanocages derived from metal−organic frameworks for ultra-high and rapid response H2S gas sensor

Rapid and effective hydrogen sulfide (H2S) detection is vital to ensure safety in industrial environments, where it is a common toxic gas. This study utilized Zn-based metal-organic frameworks (MOFs) as precursors to prepare hollow nanocage structure-like CuO/ZnO sensors. By optimizing the ratio of CuO to ZnO, the resulting CuO/ZnO nanomaterials demonstrated ultra-high sensitivity and a swift response to low H2S concentrations. The experimental results show that, thanks to its unique nanocage structure and abundant active sites on the surface, the sensor responds up to 3423 to 10 ppm H2S with a response time of only 10 seconds. In addition, the sensor exhibits good stability, selectivity and low lower detection limit at a low operating temperature of 115 °C, and the lower limit of detection for H2S reaches 100 ppb (3.04). Furthermore, the examination of the gas-sensing mechanism exposed the collaboration of CuO/ZnO nanocages in gas adsorption and electron transportation. Remarkably, the generation of p-n heterostructures greatly enhanced the sensitivity and selectivity towards H2S, while providing a model for constructing and producing high-performance and enduring sensors.