Interfacial 2D Ni-MOF Nanoarchitectures for Energy-Efficient Methane Sensing under Ambient Conditions.

At ambient temperature, methane (CH4) detection is extremely challenging yet important for a wide range of applications, including monitoring wetlands, ensuring safety on mining sites, and detecting pipeline leaks. In this regard, metal-organic frameworks (MOFs) have recently emerged as high-performing sensing platforms due to their abundant active sites, tunable porosity, and electrical responsiveness. In the present work, we successfully synthesized a rhombic, faceted, 2D-crystalline nickel-based MOF (Ni-MOF) nanosheet with well-defined edges in a solvothermal reactor. The thicknesses of nanosheets range 20-30 nm, and their surfaces were composed of Ni, C, O, and N elements, which govern the sensing properties of the Ni-MOF framework. The interdigitated electrodes Ni-MOF-based receptor demonstrates reliable methane (CH4) detection over a concentration range of from 0.2% to 1% under ambient conditions. Specifically, the receptor achieves response and recovery times <20 s, highlighting its suitability for real-time applications with minimal hysteresis. The mechanisms are predominantly associated with adsorption-induced changes in carrier density and interfacial potential at the Ni-MOF/electrode interface. Interactions between CH4 gas and Ni2+ sites in Ni-MOFs change the framework's electronic structure. The post-characterization results indicate that the Ni-MOF-based sensor can be used as a next-generation methane sensor for industrial applications.