In this study, the direct electrooxidation of sodium borohydride (NaBH4) is investigated within a liquid flow-through DBFC having a catalyst composition which varies from inlet to outlet. Electrochemical and spray coating deposition are used to form catalyst layers composed of a gradient of both thin-film and carbon-supported catalysts. The efficacy of the fuel cell design is evaluated electrochemically to understand which catalyst layer system maximizes fuel diffusion, minimizes hydroxide and hydrogen adsorption, and facilitates the removal of borate from the catalyst layer.
The characteristics of catalyst layer structure/composition before and after testing, and electrochemical efficiency for BOR are observed using several analytical techniques including scanning electron microscopy (SEM), X-Ray energy dispersive spectroscopy (X-EDS), Braunauer-Emmett-Teller sorptometry (BET), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS).
(1) Olu, P. Y.; Bonnefont, A.; Rouhet, M.; Bozdech, S.; Job, N.; Chatenet, M.; Savinova, E. Electrochim. Acta 2015, 179, 637.
(2) Stroman, R. O.; Jackson, G. S. J. Power Sources 2014, 247, 756.