Copper's early oxidation layer reveals surprising electronic properties for catalysts and nuclear waste storage

New research reveals that copper's initial oxidation layer is electronically closer to metallic copper than to copper oxide, despite high oxygen content, a finding with implications for catalyst design and nuclear waste storage. Using Auger photoelectron coincidence spectroscopy at BESSY II, scientists measured the oxidation state of copper atoms in the surface oxide at only around 0.3, challenging assumptions that high oxygen concentration dictates oxidation extent. The team also mapped the distribution of oxygen species forming the protective layer. These insights could improve copper-based catalysts for CO₂ reduction and methanol synthesis, where partially oxidized surfaces show unique activity. Additionally, a better understanding of copper corrosion supports developing safer containers for storing spent nuclear fuel.