The effect of the nature of the catalyst on the performance and mechanism of the hydrogen oxidation reaction (HOR) is discussed for the first time in this work. HOR is an anodic reaction that takes place in anionic exchange membrane fuel cells (AEMFCs) and hydrogen pumps (HPs). Among the investigated catalysts, Pt exhibited the best performance in the HOR. However, the cost and the availability limit the usage. Co is incorporated as a co-catalyst due to its oxophylic nature. Five different PtCo catalysts with different Pt loading values were synthesized in order to decrease Pt loading. The catalytic activities and the reaction mechanism were studied via electrochemical techniques, and it was found that both features are a function of Pt loading; low-Pt-loading catalysts (Pt loading < 2.7%) led to a high half-wave potential in the hydrogen oxidation reaction, which is related to higher activation energy and an intermediate Tafel slope value, related to a mixed HOR mechanism. However, catalysts with moderate Pt loading (Pt loading > 3.1%) exhibited lower E_1/2 than the other catalysts and exhibited a mechanism similar to that of commercial Pt catalysts. Our results demonstrate that Co plays an active role in the HOR, facilitating H_ads desorption, which is the rate-determining step (RDS) in the mechanism of the HOR.

The main factor that affects the performance of the arsenic removal from water is its oxidation state. It is known that As (III) is harder to be removed than As(V) due to the fact that H3AsO3 is a nonionic compound with a pK1 = 9.22 while H3AsO4 (As(V)) dissociates ready with a pK1 = 2.25. In the oxygen- poor environment like in groundwater, arsenic exists mainly as As(III). For the purpose of obtaining a higher degree of removal of arsenic from contaminated groundwater, it is necessary to oxidize the As(III) to As(V) prior to the other treatment processes. In this work an electrochemical reactor, having an anode made from reticulated vitreous carbon of 100 pores per inch (100 ppi), was used to oxidize As(III) to As (V), this eliminates the need of adding more chemical substances to the treatment system. The performance of this special designed electrochemical reactor was evaluated at various applied cell voltages, reaction time, the concentration of the supporting electrolyte (NaCl), flow rate of the arsenic (As(III)) contaminated water through the electrochemical reactor and the pH of the aqueous media. Our experimental results indicated that for an aqueous solution containing 1.0 ppm in As(III) and at 3.0 volts applied cell potential with a flow rate at 10 mL/min and 0.10 M in NaCl, the percentage of oxidation of As(III) to As(V) was closer to 100%.

We are reporting a synthesis of nickel and palladium (Ni-Pd) nanoflowers with excellent size and Calendula-like shapes using a wet-chemistry method for efficient alcohol oxidation reaction (AOR). The nanoflower structure has shown to have electrocatalytic activity to monohydric shorter carbon chain containing alcohols (C1-C4; methanol, ethanol, propanol and n-butanol). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that the Ni-Pd nanoflowers catalyst has different electronic behavior due to flower-like structure and comparatively higher degree of alloy formation. The transmission electron microscopy (TEM) images showed a Calendula flower-like shape and crystalline structure of Ni-Pd. The electrochemical properties of the catalyst have been evaluated by cyclic voltammetry (CV) and chronoamperometry (CA) in 1 M KOH electrolyte. For the first time, a comparative kinetic analysis has been investigated between four alcohol's catalysis. The higher electrocatalytic activity has increased in the order of C3 > C4 > C1 > C2. The overall AOR kinetic study has determined that the Ni-Pd is favorable due to Ni mediated alloyed formation and flower-like structure.