Highly dispersed Metal-Organic-Framework-Derived Pt nanoparticles on three-dimensional macroporous ZnO for trace-level H2S sensing

The effective detection of trace-level H2S gas is not only necessary for personal safety but is also important for understanding various physical and pathological processes in human biological systems. In this work, three-dimensional inverse opal (3DIO) ZnO sensors modified with small and well-dispersed Pt nanoparticles (NPs) are presented for ultra-low concentration H2S detection. The 3DIO ZnO skeleton, which is prepared through a simple self-assembly template method, provides fast diffusion pathways for H2S molecules and a large surface area for surface-related reactions. The optimal metal-organic framework (MOF)-derived 3DIO Pt/ZnO sensor exhibits an excellent response to trace H2S (11.2 at 1 ppm), a low detection limit (25 ppb), superior selectivity, and stability. The enhanced gas sensing performance can be attributed to the size effect of the Pt NPs and the rational design of the MOF-derived 3DIO Pt/ZnO nanomaterial. These results indicate that the strategy of combining the MOF-derived small and well-dispersed noble metal NPs with the 3DIO structure can efficiently improve the gas sensing properties for trace-level target gas determination. This method can likely be extended to similar systems based on 3DIO materials.