Summer School EMIE – Part 2
CO oxidation on Pd(100)
Date: June 2023
C. Michel
Our aim is to investigate the oxidation of CO on Pd(100). We will exploit files that were generated with the software VASP and Opt’nPath. The visualisation of results will be done using Avogadro.
The results of calculations are provided in an archive. The calculations were performed at the DFT level (PW91) using a 3-layer slab and a p(2×2) supercell for the sake of efficiency. This is below the current standard in the litterature.
The sequence is split in three steps and is expected to take 30 min.
1. CO diffusion
We start by studying the diffusion of CO. Results can be found in directories starting by 01_.
- Identify the most stable adsorption site for CO on Pd(100). The electronic energy can be found in the energy.dat file. When appropriate, the frequency list can be found in the freq.dat file.
- Propose a diffusion pathway from this most stable configuration to the closest equivalent site (e.g. top to top)
- Analyse the three pathways that were investigated combining NEB and DIMER.
2. Other reactants and products
To investigate the CO oxidation into CO2, we need also to determine the adsorption structure of O and CO2. Results can be found in directories starting by 02_.
- Identify the adsorption site of O.
- Identify the adsorption site of CO2. Measure the OCO angle.
- How would you co-adsorb CO and O in a precusor state to generate CO2?
3. CO oxidation transition state
Finally, we move to the search of the transition state corresponding to the CO oxidation into CO2. In the directory 03_CO+O, you will find the initial path generated by interpolation between the co-adorbed reactants and the product, the path optimized using NEB and then the final steps of the DIMER optimisation to convergence and the frequencies. Analyse how the path evolved from initial path to NEB to the optimized TS structure.
For more information about NEB and DIMER implementation in VASP, visit the Henkelman group’s web page.