Theoretical investigation of materials properties, catalytic activity and selectivity, reaction mechanisms, design and predict properties for industrially important materials and catalysts: study of reactions inside nanoporous zeolites, functionalized metal-organic frameworks, metals, oxides and sulfides. Structural, thermodynamics phase diagram, and catalytic cycle predictions. Establish of relationships between materials electronic structures and their properties. Screen and design for more efficient materials by doping, alloying, or functionalizing.
Reaction on Nanoporous Acid Catalysts
Understanding of economically and industrially important reactions, such as hydrocarbon transformation, CO oxidation and carbon dioxide reduction at atomistic level is challenging for designing nano-catalysts with high activity and selectivity toward desirable products. To clearly envision the reaction mechanism, state-of-the-art electronic structure theory is able to offer an excellent and practical tool that provides insight to structure and reaction mechanism complementing experiments or in certain cases, suggest and offer an important findings that is not possible by experimental investigations. Computational methods are powerful tools to study reaction mechanism and perform a high-throughput screening of the catalysts with a reasonable cost.
We investigated industrially important reactions on nano-reactors, i.e. zeolites, metal organic frameworks (MOFs), graphenes, and transition metal carbides. Charge transfers played an important role on the activity of the catalyst by governing the bond breaking and forming of molecules. In case of zeolites, long range interaction from the framework structures also contributed to assist and select the preferable transition structures in the confined spaces.
Modified MOFs for Stability, Catalytic Activity and Selectivity
We investigate the reaction mechanism of the CO oxidation on Zn+ ion in ZSM-5 zeolite and alkoxide functionalized MOF-5 by means of density functional theory (DFT). Unlike ionic ion-exchanged zeolites, metal-covalent character between Zn site and organic linker plays a key role in controlling the charge transfer to and from Zn site and in turn controls the reaction activity. In our study, organic-linker of the MOF system is modified with respect to its electron donating and withdrawing capabilities and the effect of electronic structure on the activity is evaluated. We establish the relationship to obtain activity descriptors which are useful for the molecular design and engineering process. By systematically modifying the linkers, we propose that MOFs with controllable activity are a promising platform for uniform and highly loaded metal-catalyst.
Capture and conversion of carbon dioxide (CO2
) into valuable chemicals is a critical challenge in the development of environmentally friendly, economic, and renewable energy technologies. We establish the electronic structure based model to predict efficient catalysts based on tungsten carbide with a sub-monolayer metal ad-atoms. We employ the model to tune the oxophilicity and carbophilicity of the surface and exploit to tailor catalysts with desirable product selectivity and optimized activation potential by tuning. Our approach can be used to predict site preference and binding energy trends for complex catalyst surfaces.
Intermediate adsorption governs CO2 electroreduction on metal coated Tungsten Carbides (WC).
Graphene Based Catalysts
The production of poisonous gases from the combustion of fuel, vehicles, and industrial processes is considered to be one of the big current environmental issues to be solved. Among those gases, carbon monoxide (CO) and nitrous oxide (N2
O) have been considered to be harmful gases that are emitted from an automobile exhaust.
Graphene for Green Chemistry
We employed the periodic density functional theory calculation for studying the oxidation of CO by using N2
O decomposition on Fe-Graphene as an oxidizing catalyst. Graphene is able to induce the positive charge of an Fe atom and, hence, make it ready to react with the N2
O molecule. The charge transfer between the Fe atom and the N2
O molecule was found to be important for the N2
O decomposition step. Our findings suggest that Fe-Graphene is one of the promising candidates for solving the environmentally harmful exhaust gases generated from vehicles and industrial wastes.
- Wannakao, S.; Artrith, N.; Limtrakul, J., Kolpak, A. M., ChemSusChem 8, 2745-2751 (2015).
- Maihom, T.; Wannakao, S.; Boekfa, B.; Limtrakul, J., Journal of Physical Chemistry C 117, 17650-17658 (2013).
- Maihom, T.; Wannakao, S.; Boekfa, B.; Limtrakul, J., Journal of Chemical Physics Letter 556, 217-224 (2013).
- Wannakao, S; Warakulwit, C.; Kongpatpanich, K.; Probst, M.; Limtrakul, J., ACS Catalysis. 2, 986-992 (2012).
- Wannakao, S.; Nongnual, T.; Khongpracha, P.; Maihom, T.; Limtrakul, J., Journal of Physical Chemistry C 116, 16992-16998 (2012).
- Kongpatpanich K., Nanok T., Boekfa B., Probst M., Limtrakul J., Physical Chemistry Chemical Physics 13, 6462-6470 (2011).
- Wannakao, S.; Khongpracha, P.; Limtrakul, J., Journal of Physical Chemistry A, 115, 12486-12492 (2011).
- Wannakao, S.; Boekfa, B.; Khongpracha, P.; Probst, M.; Limtrakul, J., ChemPhysChem 11, 3432 (2010).
Dr. Kanokwan Kongpatpanich (Lecturer)
Dr. Chularat Wattanakit (Lecturer)
Dr. Sippakorn Wannakao
(Postdoctoral Research Fellow)
Dr. Wattanachai Jumpathong
(Postdoctoral Research Fellow)
Mr. Taweesak Pila
Mr. Vitsarut Tangsermvit
Ms. Panchanit Piyakeeratikul
International Research Collaborator:
Prof. Alexie Kolpak
Prof. Michael Probst
University of Innsbruck
Assist. Prof. Bundet Boekfa