Analysis of Preferred Mechanisms of CO Oxidation with Atomically Dispersed Pt1/TiO2 Using the Energetic Span Model

21 December 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


This work examines the mechanisms of low-temperature CO oxidation with atomically dispersed Pt on rutile TiO2 (110) using density functional theory and the energetic span model (ESM). Of the 13 distinct pathways spanning Eley-Rideal (ER), termolecular ER (TER), Langmuir-Hinshelwood(LH), Mars-Van Krevelen (MvK) mechanisms as well as their combinations, TER with CO-assisted CO2 desorption yields the highest turnover frequency (TOF). However, this pathway is ruled out because Pt is dynamically unstable in an intermediate state in the TER cycle, determined in a prior ab initio molecular dynamics study by our group. We instead find that a previously neglected pathway – the ER mechanism – is the most plausible CO oxidation route based on agreement with experimental TOFs and turnover-determining states. The preferred mechanism is sensitive to temperature, with LH becoming more favorable than ER and TER above 750 K. By comparing TOFs for Pt1/TiO2 with prior mechanistic studies of various oxide-supported atomically dispersed catalysts in the literature, we also attempt to identify the most viable metal and support materials for CO oxidation.


atomically dispersed catalysts
reaction mechanisms
CO oxidation
energetic span model
turnover frequency
density functional theory

Supplementary materials

Supporting Information
Supporting Information contains the computational methods, complete catalytic cycles, results of Bader analysis, comparison with experimental data, and binding energy information of intermediates.


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