Excess enthalpies, densities, and speeds of sound at temperatures of (283.15, 298.15, and 313.15) K are reported for binary mixtures of β-pinene + ethanol and β-pinene + 1-propanol. Excess molar volumes have been calculated from the densities. The deviations in the speeds of sound have also been estimated. All of the properties have been fitted to Padé approximants. Excess molar enthalpies and excess molar volumes are positive for both mixtures, whereas the speed of sound deviations show negative values. The values of these properties are discussed in terms of the molecular interactions. The enthalpic and volumetric behaviors of the mixtures are compared with those of the mixtures of ethanol or 1-propanol with cyclohexane or methylcyclohexane, which are two simple hydrocarbons whose basic ring is similar to that of β-pinene.

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Polymer electrolyte fuel cells with alkaline anion exchange membranes (AAEMs) have gained increasing attention because of the faster reaction kinetics associated with the alkaline environment compared to acidic media. While the development of anion exchange polymer membranes is increasing, the catalytic layer structure and composition of electrodes is of paramount importance to maximize fuel cell performance. In this work, we examine the preparation procedures for electrodes by catalyst-coated substrate to be used with a well-known commercial AAEM, Fumasep® FAA-3, and a commercial ionomer of the same nature (Fumion), both from Fumatech GmbH. The anion exchange procedure, the ionomer concentration in the catalytic layer and also the effect of membrane thickness, are investigated as they are very relevant parameters conditioning the cell behavior. The best power density was achieved upon ion exchange of the ionomer by submerging the electrodes in KCl (isopropyl alcohol/water solution) for at least one hour, two exchange steps, followed by treatment in KOH for 30 min. The optimum ionomer (Fumion) concentration was found to be close to 50 wt%, with a relatively narrow interval of functioning ionomer percentages. These results provide a practical guide for electrode preparation in AAEM-based fuel cell research.

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