Fig. 3: Reaction mechanisms and activation of adsorbed CO molecules in reaction.
From: Electronic communications between active sites on individual metallic nanoparticles in catalysis
a Structural snapshots illustrating the DFT-calculated reaction pathway of CO oxidation on Rhmet/Al2O3 with electron-injection and electron-extraction processes involving six steps for a cycle. The gold and light gold balls represent active site Rh atoms and the other Rh atoms, respectively. The red and light red balls represent O atoms. The black balls represent C atoms. Inset: the relative free-energy diagram for Rhmet/Al2O3 following EDM or LRM. b Energy barriers of the EDM and LRM rate-determining steps of CO oxidation on Rhmet/Al2O3. ΔG represents the Gibbs free energy difference with respect to the initial state (A). c Projected density of state (pDOS) of gaseous CO molecule (left), and adsorbed CO, reactive surface lattice oxygen (O2−) and the vertex Rh active site at the adsorption states (or at A in panel (a) (middle) together with an enlargement of the rectangle closed by the red dashed lines in the middle diagram (right). The red dashed lines serve only as a visual guide in order to show the relationship between the enlargement and the original diagram. The energy level was normalized to the vacuum level and EF represents the Fermi level of Rhmet/Al2O3. The electron number on each orbital is also given. Black dashed lines show CO orbital shifts and redistribution after the CO adsorption. d pDOS of reactive CO on Rhmet/Al2O3 at the adsorption states (or at A in panel (a) and TS1.
