Dynamics of gold nanocluster on MgO surface with F-center defect and its implication for CO oxidation

V Tiwari and Dhananjay and T Karmakar, JOURNAL OF CHEMICAL PHYSICS, 163, 214715 (2025).

DOI: 10.1063/5.0287822

Gold nanoclusters supported on oxide surfaces exhibit enhanced catalytic activity due to charge redistribution at defect sites and strong metal- support interactions. In this study, we employ machine-learned interatomic potential-based simulations to investigate the dynamics of Au-8 nanoclusters adsorbed on an oxygen-vacancy (F-center) defected MgO (100) surface. On-the-fly probability-enhanced sampling (OPES) simulations driven by a graph neural network-based collective variable reveal the low-energy conformational landscape of Au-8 and the preferred binding site of CO, while machine-learned Bader charges uncover an inverse correlation between Au-Au coordination number and localized negative charge on undercoordinated Au atoms. The most stable Au-8 conformer was then used to probe CO adsorption, which shows preferential binding of CO to the most negatively charged undercoordinated Au sites. Subsequent O-2 adsorption resulted in significant charge transfer that enhances CO oxidation reactivity on the FC-defected MgO (100) surface. These findings highlight how defect-mediated charge transfer and cluster morphology together dictate adsorption behavior and catalytic functionality on oxide supports.

Return to Publications page