Activation of Copper by Decomposition into Nanoclusters Driven by CO Adsorption
Numerous clusters made of 3 and 19 atoms are formed, with edges decorated by CO. Pumping the CO away desorbs the molecules from the surface, which then becomes very active for reactions involving water dissociation. Right: STM images of a Cu(111) crystal surface in vacuum (top) and in the presence of 0.2 Torr of CO at room temperature (bottom).
Atomically flat and chemically inactive surface of Cu(111) decomposes into clusters upon CO adsorption, driven by the energy gain from CO binding to low-coordinated Cu atoms and weakening of Cu-Cu binding. The new restructured surface is highly active for catalytic reactions.
Significance and Impact
The findings provide a new paradigm to understand the origin of chemical activation of catalysts. Copper-based catalysts are used in water gas shift, methanol oxidation, synthesis, and other reactions.
- Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy operating under ambient gas pressure, were the key tools enabling this research.