Design strategy of bifunctional catalysts for CO oxidation

Abstract

The predictive power of first-principle calculations and related catalytic modeling enables people to design fuel combustion catalysts in silico, reducing the conventional trial-and-error process in experiments. Following the Sabatier principle, many catalyst design strategies focus on identifying the site with an optimal bonding strength of key adsorbates. However, this method is sometimes limited for the design of bifunctional catalysts. To address this challenge, here, we discuss a general design strategy of bifunctional catalysts where different sites on the surface are occupied by different reactants, resulting in an active interface due to a poisoning-free nature of a bifunctional surface. To further illustrate this concept, density functional theory calculations with on-site coulomb interactions (DFT + U) were performed to analyze the CO oxidation over M-X/CeO2(111) (M = Pt and Cu; X = Ag, Au, Cu, Rh, and Ru) catalysts, using a two-layer nanorod as an example. We found that Pt-Cu and Cu-Rh nanorods show a bifunctional nature for CO and O2 adsorption, leading to poisoning-free catalytic performance. In particular, the Pt-Cu system shows a theoretical activity superior to other bimetallic systems. Most importantly, we revisit a strategy that can rationally design a poisoning-free bifunctional catalyst to treat the CO gases resulting from incomplete combustion of fossil fuels.