Theoretical Investigation of O2 and CO2 Adsorption on Small PdNi Clusters Supported on N-Doped Graphene Quantum Dots

A density functional theory (DFT) investigation was conducted to study the O2 and CO2 adsorption on very small Pd3−nNin (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. First, the interaction between Pd3−nNin (n = 0–2) clusters and N-GQDs was analyzed. Subsequently, the adsorption behavior of O2 and CO2 molecules on the supported clusters was examined. The calculated interaction energies (Eint) of Pd3−nNin (n = 0–2) clusters on N-GQDs were found to be higher than those on pristine graphene, indicating enhanced cluster stability on N-GQDs. Furthermore, the adsorption energies (Eads) of the O2 molecule on the Pd3 and Pd2Ni clusters deposited on N-GQDs were similar. Meanwhile, the PdNi2 cluster deposited on N-GQDs exhibited the highest Eads (−1.740). The Eads of CO2 on Pd3−nNin (n = 0–2) clusters embedded in N-GQDs were observed to be close to or exceed 1 eV. Upon adsorption of O2 and CO2 on the Pd3−nNin (n = 0–2) clusters supported on N-GQDs, an elongation of the O–O and C–O bond lengths was observed, respectively. This structural change may facilitate the dissociation of these molecules on the supported clusters.