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Project Description

1. Ion-exchanged Zeolite for Gas Separation
2. Design of SnO2-based Oxygen Evolution Reaction (OER) Catalysts
3. Q and A

Zeolite for Gas Separation

Path:/home/liz18025/shared/cheg4995-5395/final_project/Separation

In this project, you will be calculating the adsorption free energy of Benzene(C6H6) and Thiophene (C4H4S) on the larges pore of the ZSM-5 zeolite. Due to the limitation of the computation resource, you will perform the calculation on the cut-out model, which consist of the 10-Si-atom ring(pore) and necessary surrounding atoms.

10-Si-atom Ring

Your tasks include the following:

• Using make_ring.py to generate a proper model for Zeolite simulation by adjusting the cutoff value. Make sure your structure has the same stoichiometry as SiO2 to avoid electronic converging issue. Optimize its structure with by fixing surrounding atoms.

• Calculate the adsorption free energy of Benzene and Thiophene on the 10-Si-atom ring of the pure ZSM-5.

Benzene and Thiophene

• Calculate adsorption free energy of Benzene and Thiophene on the 10-Si-atom ring of the ion-exchanged ZSM-5

• Discuss how the adsorption isotherm (separation ability) is affected by ion-exchange.

SnO2-based OER Catalysts

Path:/home/liz18025/shared/cheg4995-5395/final_project/OER

Pure SnO2 itself is one of the worst OER catalysts, due to weak binging of O species on the surface. You will be calculating the adsorption free energy of O and OH on pure and doped SnO2(110) surface to obtain the theoretical OER over-potential. The paper by Man et. al. provide a good reference for you to work on this project.

OER Activity Volcano. (Man et.al. 2011)

The universal linear scaling between ∆G_OH and ∆G_OOH helps you to asses the theoretical over-potential using a unique descriptor (∆G_O - ∆G_OH). At standard condition,

Your tasks include the following:

• Calculate the OER over-potential of pure SnO2 reduced surface, determine the most favorable binding site for O.

Reduced SnO2(110) surface. Available binding sites: Bridge and CUS(coordination unsaturated) Sites.

• Replace one of the surface Sn atom with other dopants of your choices. (at least 3 dopants and please discuss with me before submitting your jobs). For each dopant please consider the following two possible doping sites.

Two possible sites for doping guest metal (replacing Sn).

• Discuss whether and how dopants makes SnO2 better (or worse).

Q and A

1. What if my calculation didn’t finish with one submission?

Most of your calculations will run longer than your HW3, some of them may even exceed the time limit in your job submission script. In this case, you can copy relax.traj to the .traj you have in the qe-opt.py and resubmit your job. The program will read the last configuration from relax.traj and continue the optimization process.