Structural Transformation from Low-Coordinated Oxides to High-Coordinated Oxides during the Oxidation of Cu Nanoparticles

Comprehensively understanding the oxidation mechanism of copper nanoparticles (NPs) is valuable to the corrosion protection of metals and controllable preparation of Cu oxide nanoparticles. In this work, we performed reactive molecular dynamics simulations to study the oxidation behaviors of Cu NPs. Results show that Cu NP oxidation is an expanding process from the surface oxidation nuclei to their surroundings, forming an oxide film and finally growing inward. In the process of oxide film formation, the oxide changes from a low-coordination structure to a high-coordination structure. Besides, the influences of oxygen content and temperature on the oxidation process have also been discussed. Excess oxygen contents at low temperature may have less effect on the oxidation, while the temperature rise can effectively promote oxidation and growth of high-coordinated oxides. This work provides a better understanding of the atomic-scale oxidation mechanism of Cu NPs, which is helpful to design and prepare the highly active, controllable, and stable Cu NPs.

Automated summary

This study used reactive molecular dynamics simulations to investigate the oxidation behavior of copper nanoparticles, revealing the process of oxidation expansion and structural changes during oxide film formation. The effects of oxygen content and temperature on the oxidation process were discussed, showing that temperature rise can effectively promote oxidation and growth of high-coordinated oxides.