Abstract
For very small nanocluster-based catalysts, the exploration of the influence of the particle size, composition, and support offers precisely variable parameters in a wide material search space to control catalysts' performance. We present the mechanism of the CO(2) methanation reaction on the oxidized bimetallic Cu(3)Pd tetramer (Cu(3)PdO(2)) supported on a zirconia model support represented by Zr(12)O(24) based on the energy profile obtained from density functional theory calculations on the reaction of CO(2) and H(2). In order to determine the role of the Pd atom, the performance of Cu(3)PdO(2) with monometallic Cu(4)O(2) at the same support has been compared. Parallel to methane formation, the alternative path of methanol formation at this catalyst has also been investigated. The results show that the exchange of a single atom in Cu(4) with a single Pd atom improves catalyst/s performance via lowering the barriers associated with hydrogen dissociation steps that occur on the Pd atom. The above-mentioned results suggest that the doping strategy at the level of single atoms can offer a precise control knob for designing new catalysts with desired performance.