CuCr Bimetallic Catalyst for Selective Electrooxidation of Ammonia at Room Temperature

Abstract

In an effort to attain a low-cost, energy-efficient, and non-noble electro-catalyst that selectively oxidises ammonia to nitrogen at room temperatures, bimetallic carbon-supported CuxCry (x,y=1–9) catalysts were prepared and found to be more active than elemental Cu and Cr towards ammonia oxidation (AOR). Cyclic voltammetry (CV) measurements revealed an increase in activity with Cu content. Peak current density of 90 % Cu catalyst in 0.1 M KOH+0.1 M NH4OH was found to be 22 mA/mg (scan rate=20 mV/s) compared with 14.8 mA/mg for commercial Pt catalyst under the same conditions. Mass spectrometry measurements have identified higher selectivity of this catalyst towards N2 than on Cu alone. Pre-oxidation of catalyst in 0.1 M KOH (1.1 V vs RHE) was found to improve the activity and stability towards AOR over time. The potential of CuxCry (x, y=1–9) based catalysts for AOR in fuel cells is corroborated.