Novel amine-functionalized zinc-based metal-organic framework for low-temperature chemiresistive hydrogen sensing

Abstract

Low-temperature operating chemiresistive gas sensors are attractive for a variety of real-time gas monitoring applications, with benefits such as low power consumption, profitability, and miniaturization of devices. In this regard, we developed a low-temperature operating H2 gas sensor using solvothermal-processed novel amine-functionalized zinc-based metal-organic framework (Zn-BDC-NH2) as a detection material. The Zn-BDC-NH2 structure is consists of the Zn4O secondary building units and 2–aminoterephthalate acidic linker that form the 3D frame structure. Prior to sensing studies, various techniques were employed to confirm -NH2 functionalization and to characterize structure, surface morphology, thermal stability, surface area, and surface chemistry of synthesized Zn-BDC-NH2 materials. Benefitting from the simple synthesis process and larger surface area (880 m2g-1) with adequate porosity (~13 Å), Zn-BDC-NH2 has proven to be an excellent chemiresistive sensor for the effective sensing of low concentrations of H2 at 50 °C. Moreover, the sensor shown significant sensitivity to the detection of lower H2 concentrations of 1–10 ppm, a response value of 2.93–10 ppm H2, and complete recovery characteristics at 50 °C. We discussed the mechanisms for attaining the excellent H2 sensing. The utilized room temperature solvothermal approach opens up a perspective for synthesizing Zn-BDC-NH2 material with suitable functionalities and their use in low temperature H2 sensors.