Highly active and stable Au@CuxO core–shell nanoparticles supported on alumina for carbon monoxide oxidation at low temperature

Abstract

Au@Cu_xO (x = 1 or 2) core–shell heterostructure nanoparticles (NPs) are synthesized by a facile aqueous solution approach. γ-Alumina support Au@Cu_xO (Au@Cu_xO/γ-Al₂O₃) catalysts used for CO oxidation at low temperature are prepared by dispersing the core–shell NPs on the surface of γ-alumina. It proves that the formation of the core–shell structure has led to the interaction between Au and Cu_xO and the co-existence of Au^δ+ and Au⁰, which accounts for the improvement in catalytic activity. It can even catalyze CO oxidation at room temperature and the conversion of CO can reach to 38%. In the same case, Au/γ-Al₂O₃ does not have any catalytic activity. In particular, the embedding of Au NPs into Cu_xO shells has also improved the catalytic stability of Au based catalysts remarkably, which remains unchanged after 108 hours of reaction. To the best of our knowledge, Au@Cu_xO/γ-Al₂O₃ is really one of the most stable catalysts with adequate activity at room temperature.