Bimetallic Ru–Cu as a highly active, selective and stable catalyst for catalytic wet oxidation of aqueous ammonia to nitrogen

Abstract

Ru/C, Cu/C and bimetallic Ru–Cu/C catalysts are prepared via chemical reduction methods and investigated for catalytic wet oxidation of aqueous ammonia to nitrogen. It is found that the as-prepared bimetallic Ru–Cu/C catalyst is very active and selective as well stable as for selective oxidation of aqueous ammonia toward nitrogen at rather mild conditions. The results show that the Ru–Cu/C catalyst is much more efficient especially stable than the corresponding monometallic Ru/C and Cu/C catalysts, indicating the synergistic effect of Cu and Ru. These catalysts are characterized by XRD, XPS, TEM, and H2-TPR, and the results are revealed that there is strong interaction between Ru and Cu over Ru–Cu/C catalysts and the co-presence of Ru and Cu can effectively adjust the reactivity and converge of oxygen species as well as protect the Ru and Cu from leaching. The strong interaction, synergistic effect, proper oxygen nature and ability against leaching could be attributed to the excellent catalytic property of Ru–Cu/C catalyst.