Density functional theory insights into the bonding of CH3OH and CH3O with Ir(111) surface
- Institute of Research and Development, Duy Tan University, Da Nang City 550000, Viet Nam
- Faculty of Environmental and Chemical Engineering, Duy Tan University, Da Nang, 550000, Viet Nam
- Department of Chemical Engineering, School of Biotechnology, International University, Ho Chi Minh City, Vietnam Vietnam National University, Ho Chi Minh City, Vietnam.
- The University of Da-Nang, University of Science and Technology, 54 Nguyen Luong Bang, Da-Nang 550000, Vietnam
Abstract
Introduction: Understanding the adsorption characteristics of CH3OH and CH3O on the noble metal surfaces is essential for designing better catalysts for the on-board production of hydrogen from CH3OH. This study aims to provide insights into the adsorption behavior of these molecules on Ir(111) surface.
Methods: The adsorption structure, the adsorption energy, and the bonding mechanism of CH3OH and CH3O with Ir(111) surface were investigated by means of the density functional theory (DFT) calculations and the Bader charge analysis.
Results: The DFT results show that the adsorption of CH3OH and CH3O is driven by the formation of Ir–O bond at the top site of the surface by the overlap of O-2p and Ir-5d orbitals. The overlap of these orbitals is greater in the absorption of CH3O, resulting in stronger adsorption energy of CH3O (2.23 eV vs. 0.32 eV). In agreement with the adsorption strength, the charge transfer from CH3O to the surface is significantly larger than from CH3OH (0.386 e vs. 0.073 e).
Conclusion: Although driven by the same adsorption bond, the difference in the molecular characteristics leads to a marked difference in the absorption strength of CH3OH and CH3O on Ir(111) surface.