La2NiO4 Ceramic Electrodes for Hydrogen Peroxide Electroreduction
To develop the DBPFC, we are focused on finding low-cost, stable, durable, and efficient electrocatalytic materials for H2O2 reduction that can simultaneously inhibit its decomposition. H2O2 decomposition is known to proceed even on platinum, which is the most commonly used electrocatalyst. Recently, some perovskite-type oxides were found to have reasonable activity for H2O2 electroreduction in DBPFCs .
Here, La2NiO4 ceramic disks are prepared by mechanosynthesis and characterized by scanning electron microscopy and X-ray diffraction. The use of ceramic pellets as electrodes allows avoiding cross-contributions of carbon or nickel foam catalyst supports, thus preventing the influence of such effects in the evaluation of La2NiO4 activity.
Several electrochemical methods, namely cyclic voltammetry, chronoamperometry and chronopotentiometry, were used to investigate the electrodes activity for H2O2 reduction in alkaline media. These studies made possible determination of the reaction kinetic parameters as well as its coulombic efficiency. The effect of temperature on the calculated number of exchanged electrons and on the charge transfer coefficients was analyzed. Stability tests were also performed.
Then, a test laboratory DBPFC was assembled using a La2NiO4 cathode and main cell parameters (e.g., open circuit voltage, peak power density, cell voltage and current density at the peak) were evaluated for temperatures ranging from 25 to 65 ºC.
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