We present the novel potential application of imine-based covalent organic frameworks (COFs), formed by the direct Schiff reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde building blocks in m-cresol or acetic acid, named RT-COF-1 or RT-COF-1Ac/RT-COF-1AcB. The post-synthetic treatment of RT-COF-1 with LiCl leads to the formation of LiCl@RT-COF-1. The ionic conductivity of this series of polyimine COFs has been characterized at variable temperature and humidity, using electrochemical impedance spectroscopy. LiCl@RT-COF-1 exhibits a conductivity value of 6.45 × 10 S cm (at 313 K and 100% relative humidity) which is among the highest values so far reported in proton conduction for COFs. The mechanism of conduction has been determined using H andLi solid-state nuclear magnetic resonance spectroscopy. Interestingly, these materials, in the presence of controlled amounts of acetic acid and under pressure, show a remarkable processability that gives rise to quasi-transparent and flexible films showing in-plane structural order as confirmed by X-ray crystallography. Finally, we prove that these films are useful for the construction of proton exchange membrane fuel cells (PEMFC) reaching values up to 12.95 mW cm and 53.1 mA cm for maximum power and current density at 323 K, respectively.

Pt and Au are not miscible within a whole range of concentrations. To obtain PtAu alloys, severe thermal treatments are required that to provide aggregation phenomena. However, it is possible to synthesize bimetallic PtAu nanoparticles provided the proper synthesis route is employed. When they are prepared from water-in-oil microemulsions or with the impregnation technique, it is possible to obtain nanosized bimetallic PtAu particles. In contrast, other colloidal routes have been seen to be adequate for the synthesis of other bimetallic Pt-based particles, affording segregated samples with Pt- or Au-enriched zones. When alloyed, bimetallic PtAu nanoparticles display unique physicochemical properties that are different from those of monometallic and nonalloyed solids. Thus, the performance of alloyed PtAu samples as electrocatalysts for the oxygen reduction reaction is superior to that of the PtAu-segregated samples. In fact, the ability of carbon-supported bimetallic PtAu samples in the oxygen reduction reactions equals or even surpasses that of archetypal Pt/C electrocatalysts.

A novel alkaline exchange ionomer (AEI) was prepared from the radiation-grafting of vinylbenzyl chloride (VBC) onto poly(ethylene-co- tetrafluoroethylene) [ETFE] powders with powder particle sizes of less than 100 μm diameter. Quaternisation of the VBC grafted ETFE powders with trimethylamine resulted in AEIs that were chemically the same as the ETFE-based radiation-grafted alkaline anion exchange membranes (AAEM) that had been previously developed for use in low temperature alkaline polymer electrolyte fuel cells (APEFC). The integration of the AEI powders into the catalyst layers (CL) of both electrodes resulted in a H2/O2 fuel cell peak power density of 240 mW cm-2 at 50°C (compared to 180 mW cm -2 with a benchmark membrane electrode assembly containing identical components apart from the use of a previous generation AEI). This result is promising considering the wholly un-optimised nature of the AEI inclusion into the catalyst layersWe thank AGC Chemicals Europe (UK) for supplying the ETFE powders for this investigation and Chris Burt for his assistance in obtaining the SEM images. We thank the Engineering and Physical Science Research Council for supporting this research (grant numbers EP/H025340/1 and EP/I004882/1) and the Comunidad Autonoma de Madrid project RESTOENE (S2009/ ENE-1743) for funding Ricardo Escudero-Cid's summer placement at University of Surrey. We also would also like to thank US DOE Early Career Program funding (awarded to Prof William Mustain) through Award Number DE-SC001053