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Rapid and effective hydrogen sulfide (H 2 S) 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 H 2 S 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 H 2 S with a response time of only 10 s. 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 H 2 S 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 H 2 S , while providing a model for constructing and producing high-performance and enduring sensors. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) hierarchical hollow microsphere WO 3 and Ag 2 O/WO 3 heterojunction materials were prepared by a simple hydrothermal method for a highly sensitive continuous response H 2 S gas sensor. The results show that compared with the original WO 3 (Ra/Rg=12.5, 10 ppm, 70℃), the sensor based on Ag 2 O/WO 3 has excellent H 2 S sensing performance at 60℃. Including ultra-high sensitivity (Ra/Rg=207.12, 10 ppm), continuous detection of different concentrations of H 2 S gas (0.05–50 ppm), fast response capability (15 s), low detection limit (50 ppb), high selectivity and reliable stability. The study of gas sensing mechanism shows that the synthesized 3D hierarchical hollow microsphere structure provides more channels for gas diffusion and transmission. The dispersion of Ag 2 O nanoparticles (NPs) on the surface of WO 3 provides more reactive sites for gas adsorption. At the same time, the charge transfer is promoted by constructing Ag 2 O/WO 3 p-n heterojunction. Sulfurization of Ag 2 O improved the response value and selectivity to H 2 S gas. These factors together determine the superior performance of the prepared Ag 2 O/WO 3 H 2 S-based sensor. • Three-dimensional Ag 2 O/WO 3 p-n heterojunction hierarchical hollow microsphere were synthesized by hydrothermal method. • The response value of Ag 2 O/WO 3 sensor to 10ppm H 2 S at 60℃ is 207.12, which is the highest reported in the literature. • The Ag 2 O/WO 3 sensor can continuously detect 0.05-50 ppm H 2 S gas with a detection limit as low as 50 ppb. • The enhanced performance depends on the special material morphology, p-n heterojunction and Ag 2 O vulcanization reaction. [ABSTRACT FROM AUTHOR]