Silver Nanoparticles anchored UiO-66 (Zr) Metal-Organic Framework (MOF) based Capacitive H2S Gas Sensor
Hydrogen sulfide (H2S) is a highly poisonous gas that, when in a work place, must be identified immediately at concentrations greater than 10 ppm. Although there are numerous reports on sensing H2S gas using various techniques and approaches, there still exist a gap in terms of limit of detection (LOD) and feasibility. In this work, we demonstrate capacitive H2S sensing for the first time using metal organic frameworks (MOFs) decorated with Silver oxide (Ag2O) nanoparticles as the sensing material. The nanoparticles were deposited on three MOFs (UiO-66(Zr) BDC, UiO-66(Zr) BDC-NO2, and UiO-66(Zr) BDC-N3) using impregnation technique. The sensing materials were characterized for morphology using x-ray diffraction, scanning electron microscopy, and x-ray photoelectron spectroscopy techniques. The synthesized MOFs were coated on interdigitated electrode capacitors as dielectric material and a comparison of their sensing properties are presented among which UiO-66(Zr) BDC-NO2 loaded with Ag2O showed the highest sensitivity towards H2S. The optimized MOF-Ag2O composite demonstrated an experimental LOD of 1 ppm of H2S at room temperature showing a high chemical absorption affinity towards H2S. The work presented here is promising for developing sensitive H2S sensors and in addition paves the way to explore and develop other possible MOF based composite materials for gas sensing application.