A Highly Sensitive and Flexible Metal–Organic Framework Polymer-Based H₂S Gas Sensor

Abstract

We report the fabrication of a novel metal−organic framework (MOF)−polymer mixed-matrix flexible membrane for the detection of hydrogen sulfide (H 2 S) gas at room temperature. This high-performance gas sensor is based on MOF-5 microparticles embedded on a conductivity-controlled chitosan (CS) organic membrane. The conductivity of the organic membrane is controlled by blending it with a glycerol ionic liquid (IL) at different concentrations. The sensor showed a remarkable detection sensitivity for H 2 S gas at a concentrations level as low as 1 ppm at room temperature. The MOF-5/CS/IL gas sensor demonstrates a highly desirable detection selectivity, fast response time (<8 s), recovery time of less than 30 s, and outstanding sensing stability averaging at 97% detection with 50 ppm of H 2 S gas. This composite having high sensitivity, low-power consumption, and flexibility holds great promise for addressing current challenges pertinent to environmental sustainability.

Flexible Cu3(HHTP)2 MOF Membranes for Gas Sensing Application at Room Temperature

“…It is, therefore, the synergistic effect of the highly connected molecules of the proposed nanocomposite membrane that explains its high efficiency and sensitivity toward H 2 S gas. The high porosity of the MOF component of the composite membrane was previously proven to contribute to the passage of H 2 S molecules within the composite membrane [ 38 ]. The current findings support the contribution of the highly porous MOF structures in the construction of a gas sensor assembly.…”

“…Moreover, ILs are suitable to be used for the fabrication of electrochemical sensors as they are environmentally friendly [ 32 , 33 ]. It has been shown that glycerol-IL can be used effectively to control the conductivity of PVA membranes [ 37 , 38 ], thus, it will be utilized in this work. A volume of 5 vol% of IL (glycerol) was mixed in a 20 mL of the PVA stock solution, which was also doped with Cu-MOF that was suspended in 2.5 mL of DW at 70 °C.…”

“…The device fabrication was accomplished by sandwiching a 1 × 1 cm 2 piece of the membrane between Cu metal plate and stainless steel mesh (H 2 S resistant) with a mesh size of 200 μm as outlined in our previous study [ 38 ]. Bronkhorst mass flow controllers (MFC) were employed to dilute the test gas using synthetic air and deploying the mixture into the test chamber.…”

Metal-Organic-Frameworks: Low Temperature Gas Sensing and Air Quality Monitoring

“…By taking advantage of the cage-bridge structure of MOF-5 ([Zn 4 O(BDC) 3 ] n ), Ali et al [95] developed a high-performance gas sensor for the low concentration detection of H 2 S gas molecules (1 ppm) at room temperature. The sensing components of the device consisted of MOF-5 microparticles, blended and embedded in a conductivity-controlled chitosan organic membrane resulting in the fabrication of a flexible gas sensor (Figure 5f, inset).…”

Organic/Inorganic-Based Flexible Membrane for a Room-Temperature Electronic Gas Sensor

“…Organic polymers, such as PVA, are characterized by their wide abundance and their known promising properties, such as flexibility, environmental friendliness, thermal stability and the ability to form electrolytes by virtue of their hydrophilic nature [35]. Moreover, the conductivity of PVA can be controlled by doping it with an ionic liquid (IL), such as glycerol [36][37][38]. These combined properties can be further exploited by doping the polymer matrix with materials that have an affinity toward the detection of H 2 S gas, so that changes in their conductivity or resistivity can be recorded.…”