Two acidic coordination polymers containing uncoordinated carboxyl groups: Syntheses, crystal structures and proton conductivities in Nafion composite membranes

A simple MOF constructed using Pb(ii) with strong polarizing force: a filler of Nafion membrane to increase proton conductivity

“…For Pb-MOF, when the doping amount was 7%, the σ H+ value of the composite membrane was highest and 2.14 times that of the pure Nafion membrane at 353 K. The improvement degree of Pb-MOF/Nafion-7 obtained in this work was higher than that of most reported Nafion composition membranes doped with MOFs modified by –SO 3 H, –COOH, –NO 2 , etc. 21,24–29,40–42…”

“…For Pb-MOF, when the doping amount was 7%, the σ H+ value of the composite membrane was highest and 2.14 times that of the pure Nafion membrane at 353 K. The improvement degree of Pb-MOF/Nafion-7 obtained in this work was higher than that of most reported Nafion composition membranes doped with MOFs modified by -SO 3 H, -COOH, -NO 2 , etc. 21,[24][25][26][27][28][29][40][41][42] Proton conduction mechanism of membranes Just as the results of the characterization and AC impedance of Pb-MOF/Nafion-x composite membranes mentioned above, the doped Pb-MOF particles can interact with Nafion membrane, improve the water absorption and thermal stability of composite membranes and increase their proton conductivities at high temperatures. According to these results, the mechanism of Pb-MOF doping improving σ H+ value of composite membranes and the relationship between structure and property of Pb-MOF/Nafion-x composite membranes was observed to offer some ideas for designing excellent MOF fillers and improving the proton conductivity of Nafion PEM.…”

“…23 In our previous work, several MOFs containing uncoordinated and protonated carboxylic groups were obtained by controlling the reaction conditions. [24][25][26][27] It was found that MOFs containing acidic -COOH groups or long-range ordered hydrogen bonds exhibited more excellent proton conduction performances than MOFs with deprotonated carboxylate groups or short-range ordered hydrogen bonds. Wu's group modified the classical UiO-66 MOFs with -SO 3 H and -NH 2 functional groups, and the σ H+ values of the obtained UiO-66-SO 3 H/Nafion and UiO-66-NH 2 /Nafion membranes were 2.21 and 1.64 times that of the pure Nafion membrane, respectively.…”

Two Terbium Metal–Organic Frameworks Showing Fluorescence Sensing and Proton Conductivity

“…Introducing acidic functional groups of high proton carriers such as −COOH and −SO 3 H into organic ligands is one of the common strategies to improve the proton conductivity of materials. , The H 2 ADBA ligand contains two −COOH functional groups and both MOFs 1 and 2 have good water stability, so the proton conductivities of MOFs 1 and 2 were studied. , The crystals were ground and pressed into a smooth cylinder with a mechanical tablet press (the actual thickness is measured using a Vernier scale). Conductivity σ is calculated by the formula σ = L / RS , , where L is the thickness of the prepared sample (the thicknesses of samples are 0.048 cm for MOF 1 and 0.050 cm for MOF 2 ), S is the surface area of the prepared sample, and R is the resistance value of the measured sample.…”