The zeolitic imidazolate frameworks (ZIFs) ZIF-8, ZIF-67, and a Zn/Co bimetallic mixture (ZMix) were synthesized and used as fillers in the preparation of composite sulfonated poly(ether ether ketone) (SPEEK) membranes. The presence of the ZIFs in the polymeric matrix enhanced proton transport relative to that observed for SPEEK or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained by electrochemical impedance spectroscopy (EIS), and the temperature and frequency dependence of the real part of the conductivity were analyzed. The results at different temperatures show that the direct current (dc) conductivity was three orders of magnitude higher for composite membranes than for SPEEK, and that of the SPEEK/ZMix membrane was higher than those for SPEEK/Z8 and SPEEK/Z67, respectively. This behavior turns out to be more evident as the temperature increases: the conductivity of the SPEEK/ZMix was 8.5 × 10−3 S·cm−1, while for the SPEEK/Z8 and SPEEK/Z67 membranes, the values were 2.5 × 10−3 S·cm−1 and 1.6 × 10−3 S·cm−1, respectively, at 120 °C. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and an analysis of tan δ was carried out for all of the membranes under study. Using this value, the diffusion coefficient and the charge carrier density were obtained using the analysis of electrode polarization (EP).

Graphene cryogels synthesis is reported by amine modification of carboxylated graphene oxide via aqueous carbodiimide chemistry. The effect of the amine type on the formation of the cryogels and their properties is presented. In this respect, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), were selected. The obtained cryogels were characterized by Fourier Transformed Infrared spectroscopy, thermogravimetric analysis, X-ray spectroscopy, and Scanning electron microscopy. The CO2 adsorption performance was evaluated as a function of amine modification. The results showed the best CO2 adsorption performance was exhibited by ethylenediamine modified aerogel, reaching 2 mmol g−1 at 1 bar and 298 K. While the total N content of the cryogels increased with increasing amine groups, the nitrogen configuration and contributions were determined to have more important influence on the adsorption properties. It is also revealed that the residual oxygen functionalities in the obtained cryogels represent another paramount factor to take into account for improving the CO2 capture properties of amine-modified graphene oxide (GO)-based cryogels.

In this study, nanocomposite membranes were prepared by mixing of 1, 3, and 5% wt cobalt-based zeolitic imidazolate framework (ZIF-67) with a sulfonated poly(ether ether ketone) (SPEEK) matrix. The films named SPEEK, SPEEK-Z1, SPEEK-Z3, and SPEEK-Z5 were obtained by the casting method and then characterized by several techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and electrochemical impedance spectroscopy (EIS). Ion-exchange capacity (IEC) and water uptake (WU) were also measured. Subsequently, the polymeric nanocomposite membranes were tested in a H 2 /O 2 single cell to evaluate their performance. Our results show that the proton conductivity of nanocomposite membranes increased with the addition of ZIF, obtaining the best value of 0.014 S cm −1 for the SPEEK-Z1 membrane. Furthermore, the thermal stability of the nanocomposite membranes improved considerably with the ZIF addition. Polymer electrolyte membrane fuel cells (PEMFC) performance experiments showed promising results for these membranes working at intermediate temperatures above 100 °C, although a proper optimization process is still required.

Ultra-light eco-friendly graphene oxide (GO)-based aerogels are reported by simple one-step solvothermal self-assembly. The effect of varying parameters such as C/O ratio of GO; reducing agent amount; temperature; and duration on the properties of the aerogels was studied. The structural and vibrational features and hydrophobic surface properties of the obtained aerogels were obtained by XRD; FTIR; XPS; Raman; SEM; and contact angle measurements. The effect of synthesis conditions on the engine oil and organic solvent absorption properties was assessed. The results indicated that the lower the C/O ratio of GO, the better the absorption properties, with the best performance for oil uptake reaching 86 g g−1. The obtained results indicate the approach based on ice-templating and the tailoring of oxygen content in GO make the resulting aerogels potential candidates for use in oil spill and organic solvent treatments.

PBI composite membranes containing 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-NTf2) at 1, 5, 10, 20 and 50 wt% have been prepared and the conductivity has been analyzed by electrochemical impedance spectroscopy.