Local Strain Tuning in Cu Nanoparticles through Glucose-Mediated Synthesis.

Cu nanoparticles are widely used in different fields. Controlling the Cu oxidation state and the local strain is fundamental for optimizing its efficiency in processes, such as catalytic reactions. In this work, Cu nanoparticles were synthesized by using glucose as a reducing agent. Different synthesis conditions led to nanoparticles with a tunable local strain and Cu(0)/Cu2O ratio. The amounts of Cu(0) and Cu2O are directly related to the local strain in the nanoparticles. The lower amount of Cu(0) gives a longer Cu-Cu distance, and the lower amount of Cu2O is associated with longer Cu-O distances. It can be attributed to the creation of interfacial strain at the Cu(0)/Cu2O boundaries, as demonstrated by molecular dynamics simulations. Furthermore, the Cu(0) phase is stable at least up to two years in the air due to the presence of gluconate at the surface. This study shows that interfacial strain can be manipulated without the addition of other elements through a facile route.