Carbon Support Curvature Modulates CO2 Activation on Molybdenum Carbide Clusters

Abstract

Density functional theory (DFT) is employed here to investigate the CO2 adsorption and activation on the representative Mo6C5 nanoparticle supported on both flat and curved graphene, with particular focus on the effects of support curvature. In the free-standing nanoparticle, a locally metal-rich triangular Mo3 site exhibits the strongest CO2 binding. However, this highly reactive site anchors to carbon support, thus becoming inaccessible for adsorbates, simultaneously conferring enhanced CO2 activation capability to remaining stoichiometric Mo-C sites. Support curvature provides an additional lever: MoCy NPs in convex regions further strengthen CO2 adsorption, whereas those in concave regions thermodynamically and kinetically favor CO2 dissociation, thereby facilitating subsequent conversion steps. These findings reveal the dual structural and electronic roles of carbon supports, which pave the way for designing more tailor-made MoCy/C-based catalysts for CO2 utilization.