Rational Design of Bimetallic Metal Chalcogenide Clusters for CO2 Dissociation.

Abstract

Thermochemical dissociation of CO2 on pure, ligated, and mixed transition metal (W, Cu) chalcogenide clusters are investigated using the first-principles gradient-corrected density functional approach. It is shown that although the pure and ligated metal chalcogenide clusters exhibit significantly high barriers for CO2 dissociation, the computed barriers for the mixed clusters are relatively lower. The lowest barrier is obtained for the Cu3W3Se8 cluster, which shows a dramatically reduced barrier height of only 0.41 eV. Detailed analysis reveals that the substitution of W by Cu sites leads to a charge transfer from Cu to W sites, resulting in locally active W sites. The lowering of the CO2 dissociation barriers can be attributed to the facile transfer of charge from the locally active W sites and also due to the alteration of the binding energy of CO2 to the charged W sites. Our studies provide an alternate strategy to design novel thermochemical catalysts for CO2 adsorption and subsequent dissociation.