Dissertation: Computational modeling guides catalyst design and wastewater treatment (Ibrahim)

By integrating computational modeling with experimental observations, the new dissertation demonstrates the powerful role of density functional theory (DFT) in explaining and predicting surface activity and selectivity across both catalytic and environmental applications. The insights gained provide valuable guidance for designing more selective catalysts, optimizing syngas conversion processes, and developing efficient materials for wastewater purification.

Unraveling catalytic performance using DFT

Catalysis is the science of accelerating a chemical reaction using a substance called a catalyst. Most catalytic processes are based on heterogeneous catalysis, involving a solid catalyst and reactants in either the gas or the liquid phase. Effective catalysts must be stable, active, and selective-accelerating desired reactions while suppressing unwanted side pathways.

- I investigate the partial hydrogenation of alkynes into alkenes on PdAg single-atom alloy surfaces, revealing that catalytic selectivity is controlled by the nature of the active site and the molecular size of the reacting alkyne, explains Doctoral Researcher Hanan Ibrahim from the University of Jyväskylä.

Further studies examine acrolein selective partial hydrogenation on ligand-modified Pd(111) surfaces, where surface-bound ligands improve the selectivity by creating pocket-like environments for acrolein hydrogenation.

- The DFT results demonstrate that acrolein adopts a flat geometry in the pocket similar to its geometry at low coverage, making the hydrogenation of the C=O bond possible with a low activation energy, favoring propenol formation, says Ibrahim.

The dissertation also explores higher alcohol synthesis (HAS) from syngas over a fully dispersed CuFe(211) surface with a Cu:Fe ratio of 1:1. Thermodynamic and kinetic analyses show that methane formation is strongly favored, highlighting how surface composition and reaction energetics influence product distribution.

- These results indicate that the CuFe surface is not suitable for producing long-chain alcohols, guiding future catalyst development strategies, spesifies Ibrahim.

DFT reveals pollutant removal mechanisms

In addition to catalytic reactions, the thesis investigates the removal of methylene blue (MB) from wastewater using a pyrolyzed cellulose-MOF (P-cell-MOF). Experimental characterization reveals that the P-cell-MOF is composed of four components—Fe, Fe₃C, Fe₃O₄, and graphene—which collectively contribute to its adsorption behavior.

- Our DFT results show that MB is chemisorbed on Fe and Fe3C, while it is physisorbed on Fe3O4 and graphene. These findings clarify the distinct roles of each material within the composite and highlight how DFT calculations can uncover the underlying mechanisms of pollutant removal at the atomic scale, says Ibrahim.

MSc Hanan Ibrahim will defend her doctoral dissertation “Understanding surface reactions over metal-based surfaces via first-principles calculations” in the field of Computational Chemistry at the University of Jyväskylä on Wednesday 10.12.2025 at 12:00 in Ylistönrinne Campus in lecture hall FYS1. The opponent will be Professor Anders Hellman (Chalmers University), and the custos will be Professor Karoliina Honkala (University of Jyväskylä). The defense will be held in English.

The dissertation “Understanding surface reactions over metal-based surfaces via first-principles calculations” is available online on the JYX publication archive: https://jyx.jyu.fi/jyx/Record/jyx_123456789_107109

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