(399g) CO2 Activation on Zr-Decorated, Cu Nanoparticles

Cu-based catalysts are good candidates for the conversion of CO₂, a greenhouse gas, into fuels and chemicals, such as formic acid and methanol. In this work, density functional theory calculations have been applied to investigate the role of Zr decoration on the structural and electronic properties of Cu₅₅ nanoparticles and its behavior towards CO₂ adsorption. The Zr decoration is thermodynamically preferred on the corner (surface) sites of the nanoparticles. This decoration results in strong CO₂ chemisorption which does not occur in the case of the monometallic Cu₅₅. By further increasing the Zr composition in Cu_55-xZr_x nanoparticles (with x=2-12) we observed a significant enhancement in the CO₂ adsorption starting at the composition Cu₄₇Zr₈. The CO₂ molecule is shown to be activated upon chemisorption on the Zr-decorated, Cu-based nanoparticles, transitioning from a linear to a bent configuration. Charge transfer from the nanoparticle to the CO₂ molecule was found to be responsible for the observed activation. Furthermore a linear relationship between the total charge transferred to CO₂ and the ionization potential (IP) of the nanoparticles was observed. Finally, a model has been developed that is able to predict Cu nanoparticle morphologies with Zr decoration over various nanoparticle sizes, which could potentially show enhanced CO₂ adsorption and activation.