First principle study on alkali metals promotion of CO oxidation over Ir(100)

Abstract

The effects of adsorption of lithium and potassium atoms on CO oxidation at Ir(100) surface are investigated by using density functional theory (DFT) within generalized gradient approximation (GGA). The reaction path, transition state, and energy barrier are obtained by using climbing image nudged elastic band method (CI-NEB). The results of CO oxidation on Ir(100)-(3 Â 2) clean surface indicate that the energy barrier is related to the changes of energy that caused by the movements of the reactant from the initial state to the transition state. The coadsorption of A (A for alkali, A ¼ Li or K) atoms on Ir(100)-(3 Â 2)-(CO-O) system promote the CO oxidation. In particular, the alkali atom induces changes in the reaction path and energy barrier. Potassium atom induces a large reduction in the reaction barrier more than Li atom. K atom interacts directly with the reactant, which stabilizes the reactant and increases the reactivity of the catalyst. The bent CO 2 appears at the transition state for CO oxidation reaction on both alkali-precovered Ir(100) surface (A ¼ K or Li).

Catalytic Soot Combustion─General Concepts and Alkali Promotion

“…In practice, a combination of two or more of the aforementioned effects that contribute to the overall catalytic performance is often observed. Recent investigations into the role of alkali promotion in catalytic processes involved molecular modeling (density functional theory calculations), providing in-depth insights into the geometric and electronic structures of catalytic surfaces or active phases, reaction pathways, energy barriers, intermediates, or transition states. ,− …”

Application Prospect of K Used for Catalytic Removal of NOx, COx, and VOCs from Industrial Flue Gas: A Review

“…The O 2 adsorbed on K 2 O reacts with the CO adsorbed on the adjacent Pt site to complete the oxidation of CO, and then the reaction pathway between CO and O 2 is changed from the competitive adsorption reaction on single active site to the non-competitive adsorption reaction on double active sites. The addition of K on Pt-based [140], Ir-based [152], and Au-based catalysts [151] has been found to change the reaction pathway which significantly reduces the reaction barrier and the disproportionation reaction of CO occurs on Au/TiO 2 , as shown in Equation (10).…”