CO oxidation over nobel metals supported on copper oxide: effect of Cu+/Cu2+ ratio

In this work, CuO supported with 0.5, 1 and 3 wt.% Au or Pd nanoparticles were synthesized. The activity of the synthesized catalysts was tested in the highly environmentally impacted carbon monoxide oxidation reaction. A variety of physicochemical characterization tools were applied to study the catalysts. The results confirmed the formation of a mixture of Cu+/Cu2+ species after Au or Pd nanoparticles deposition, with a higher ratio in the case of Pd rather than Au nanoparticles. The results also confirmed the enhancement of CuO reducibility and the formation of a higher ratio of surface lattice oxygen especially in Pd supported catalysts. The catalytic activity study showed a direct relation with Nobel metal and its size, Cu+/Cu2+ and surface lattice oxygen ratios, where 3PdCuO exhibited a total conversion of CO at 47 °C. The catalysts also showed high stability and durability for 24 h with 100% CO conversion under the reaction conditions.