Uncovering the structural, electronic and vibrational properties of atomically precise PdmCun clusters and their interaction with CO2 molecule.

Abstract

In this work, we address the structural stability, electronic properties and effect of metal-metal interaction on Raman spectra of icosahedral (Ih) PdmCun (m+n=13) clusters using first principles calculations based on dispersion-corrected density functional theory (DFT-D2). Initially, we investigated the relative stability of Ih PdmCun clusters over monometallic Ih Pd13 and Cu13 clusters by calculating the average binding energy per atom, mixing energy, second order energy difference and average bond length. The Ih Pd5Cu8 is the most stable bimetallic cluster with the 2.88eV, -0.218eV and 0.678eV average binding energy per atom, mixing energy and second order energy difference, respectively. The main goals of the present study are to figure out the chemical enhancement, modulation in electronic properties and Pd-Cu bond length in Ih PdmCun clusters after systematic doping of Cu-atom. Further, to examine the doping effect of Cu atom in Pd cluster, we have also analysed the Raman spectra of Ih PdmCun clusters. In case of Ih Cu13 cluster, the contraction of Cu-Cu bond length as compared to its bulk form resulted in a significant blue-shift of characteristic Raman peak (212cm-1) of Ih Pd13 cluster. Finally, the interaction mechanism of the CO2 gas molecule over Pd-Cu alloy clusters have also been studied to understand the effect of composition on reactivity of CO2 gas molecule.