Design and Preparation of a Superior Proton Conductor by Confining Tetraethylenepentamine in the Pores of ZIF-8 To Induce Further Adsorption of Water and Carbon Dioxide

Abstract

In this work, we present a new strategy toward the design and preparation of a metal−organic framework-or porous coordination polymer-based superior proton conductor. We chose a robust metal−organic framework, ZIF-8, as the host and a flexible aliphatic alkylpolyamine, tetraethylenepentamine (TEPA), as the guest, and we successfully prepared an encapsulation compound TEPA@ ZIF-8 via the facile insertion of TEPA into the pores of ZIF-8, which was characterized by microanalysis, thermogravimetric analysis, IR spectroscopy, N 2 , water vapor adsorption− desorption, and other methods. Each cage in ZIF-8 is occupied by ∼1.

Proton Conduction of an Acid-Resistant Open-Framework Chalcogenidometalate Hybrid in Anhydrous versus Humid Environments

“…As shown in Figure a and Figure S7, the proton conductivity of 1 significantly improved when increasing the relative humidity between 43 and 99%, with the values varied from 6.06 × 10 –7 S cm –1 at 43% RH to 1.90 × 10 –5 S cm –1 at 75% RH and 4.86 × 10 –5 S cm –1 at 99% RH. This phenomenon of highly humidity-dependent proton conductivity also commonly appeared in water-assisted MOF-based proton conducting materials, − implying that the adsorbed water molecules have an important role in constructing the well-defined hydrogen-bonding network that functions as an effective proton-transport pathway in the framework. Furthermore, the water-adsorption/desorption isotherm in Figure b showed the amount of water molecules being adsorbed increased when increasing the relative water-vapor pressure, which further demonstrated that this hybrid material can adsorb more water molecules into the channels under higher relative humidity.…”

High Proton Conductivity in Nafion/Ni-MOF Composite Membranes Promoted by Ligand Exchange under Ambient Conditions

“…MOF pellets were sealed for 24 h in different humidities and equilibrated for 30 min under each test condition before the AC impedance test. The relative humidity was controlled by different saturated salt solutions, which were solutions of H 2 O (100% RH), Na 2 SO 4 (93% RH), KCI (87% RH), NaCl (75% RH), and NaBr (58% RH). ,,− Nafion/MOF composite membranes were cut into circles with a 5 mm diameter. The thickness was measured to be 0.2 mm.…”

Pore size effects on high-efficiency proton conduction in three stable 3D Al-based MOFs modified with imidazole

“…Three new proton conduction composites Im@1-3 were successfully obtained by encapsulating imidazole molecules into the pores of 1-3. [36][37][38] The proton conduc-tion behaviors of 1-3 and Im@1-3 were investigated via their alternating current (AC) impedance spectra under different controlled humidities and temperatures. [39][40][41] Amazingly, with the aperture sizes of 1-3 decreased, their proton conductivities increased significantly under the same conditions.…”