The Effects of CeO2 Inclusion in the Electrocatalytic Properties of Nanoparticles for an Ammonia Oxidation Electrocatalyst

Abstract In the quest for advancing renewable energy technologies with high energy density fuels, a certain interest in Fuel Cells has been developed. Currently the focus is on nitrogen containing fuels, such as ammonia (). This primarily because the oxidation will predominantly yield dinitrogen (). This means that these sustainable fuel cells can render a carbon free energy process. For the electro-oxidation of ammonia () an electrocatalyst is required to catalyze the reaction. This is due to the fact that the ammonia oxidation reaction is difficult and can only be achieved on noble metals (). Because of this, there are complications on an industrial scale application since is not cost efficient. The project aims to develop an ammonia alkaline fuel cell (AAFC) using -based nanocatalyst to enhance the ammonia electro-oxidation. Different precursors ( vs ) were used to analyze the electrocatalytic effects of metal oxide addition (Fe 2 O 3 vs CeO 2 ) and the potential for ammonia oxidation. To determine the correct conditions to add the metal oxides onto the nanoparticles, two protocols were established. In protocol 1, was added before the particle cleaning procedure. In protocol 2, was added after the cleaning procedure. The Cyclic Voltammetry method was then applied to study the electrocatalytic activities of alloys at 20 mV/s scan rate. For the results from protocol 1, the addition of on samples from showed a slight shift to lower onset potential, meanwhile in samples from the precursor this did not occur. Onset potential was reduced form -0.386 V (control sample from without ) to -0.472 V when was added with 20 min sonication. The behavior for onset potential from protocol 2 was similar to protocol 1, but more electrical noise is visible with this protocol for samples from the precursor. According to its more defined hydrogen peak separation from the hydrogen desorption region and the energetic difference in the -oxide reduction region the nonchlorinated precursor shows better facet exposure. Through a combined analysis of SEM images and electrochemical experiments, a difference in electrochemical surface area was seen. For the chlorinated precursor () 22.0 electrochemical surface area was found while the nonchlorinated precursor ( ) had 12.8. The addition to the nanoparticles significantly reduced the electrochemical surface area in both precursors. No significant difference was found between the onset potential for the ammonia oxidation of particles and precursors. Currently we are exploring the electrocatalytic activities of nanoparticles when combined with Fe 2 O 3 .