Enhancement of Electrochemical Oxidation of Ammonia and Ammonium Carbonate over Pt Black Catalysts through Interaction with Manganese Dioxide Nanoparticles

Abstract

In this study, the potential of ammonia (NH 3 ) and ammonium carbonate ((NH 4 ) 2 CO 3 ) was investigated as alternative fuels of the fuel cell platform. Considering that the anodic oxidation activity of the ammonia compounds is the key for the overall cell performance, this study focused on its improvement by way of including a catalytic additive, which aided in decreasing the use of a precious metal catalyst. Manganese dioxide (MnO 2 ) was chosen for that purpose. Four different types, specifically alpha (α), beta (β), gamma (γ), and delta (δ), were prepared and tested via an electrochemical analysis. A cyclic voltammetry (CV) test was performed with physically mixed catalytic compositions as nanocomposites, such as 20:80, 50:50, 80:20, 90:10, and 95:5. Among these, only 95 wt % Pt and 5 wt % γ-MnO 2 exhibited an intended activity increase. Although the replaced amount of Pt was not very substantial, the increase in power density at least doubled in a single cell test. This study supported the notion that ammonia and its derivative can indeed serve as feasible fuel alternatives when a right catalyst is used, though further and systematic investigation is warranted for the realization.