A pursuit of photocatalytic water splitting in first-principles computations
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium L6, Linnanmaa campus
Topic of the dissertation
A pursuit of photocatalytic water splitting in first-principles computations
Doctoral candidate
Master of Science Joran Celis
Faculty and unit
University of Oulu Graduate School, Faculty of Science, Nano- and molecular systems research unit
Subject of study
Physics
Opponent
Professor Stephen Urquhart, University of Saskatchewan
Custos
Professor Wei Cao, University of Oulu
A search of catalytic materials for light-induced water splitting in quantum mechanics simulations
Photocatalytic water splitting is a potential alternative driving mechanism for solar panels. The process consists of a multitude of underlying atomic-scale processes proceeding over a photocatalyst material. Overall, sunlight energy and water molecules are converted into oxygen and hydrogen gases. In turn, hydrogen gas may serve as a valuable clean fuel or a chemical reagent. To make the endeavour worthwhile, however, a suitably cheap and high-performing photocatalyst material is yet to be discovered.
This thesis approaches the topic initially from a top-down perspective, covering the societal significance of the development of the technology. It could contribute to clean energy generation in the future, which is recognised as a key aspect in the response to global warming. Secondly, the physicochemical working principles of photocatalytic water splitting are explained as apparent in real systems. The parallels and differences are drawn between photocatalytic water splitting and the competing technology of photovoltaics wired to electrolysers. This yields a rational perspective on promising research directions.
Next, the pursuit of photocatalytic water splitting continues from the bottom-up. Density functional theory is introduced as a way of approximately calculating the electronic structure of an atomistic material model. Starting from this basic outcome, many other properties can be calculated that relate to the photocatalytic functionality towards water splitting. In turn, the properties of the computational models are predictive of the behaviour of real materials in the laboratory. Therefore, the computational outcomes may guide and inspire experimental research towards successful innovation.
Having introduced a series of computational methods, three original research publications are presented in which the methods are applied in practice. Amongst many findings, the experimentally observed growth of Cu-S nanoplatelets on MoS2 was linked to the surface interactions with the ethylene glycol solvent. An extensive set of γ-PC/WS2 bilayer configurations was assessed, revealing property dependencies on the twist-angle and internal strains. Furthermore, a complex LaZr16S32/Co14Ni14O45(OH)11 nanostructure was deduced, for which an elaborate combination of DFT based material properties suggests excellent photocatalytic performance.
This thesis approaches the topic initially from a top-down perspective, covering the societal significance of the development of the technology. It could contribute to clean energy generation in the future, which is recognised as a key aspect in the response to global warming. Secondly, the physicochemical working principles of photocatalytic water splitting are explained as apparent in real systems. The parallels and differences are drawn between photocatalytic water splitting and the competing technology of photovoltaics wired to electrolysers. This yields a rational perspective on promising research directions.
Next, the pursuit of photocatalytic water splitting continues from the bottom-up. Density functional theory is introduced as a way of approximately calculating the electronic structure of an atomistic material model. Starting from this basic outcome, many other properties can be calculated that relate to the photocatalytic functionality towards water splitting. In turn, the properties of the computational models are predictive of the behaviour of real materials in the laboratory. Therefore, the computational outcomes may guide and inspire experimental research towards successful innovation.
Having introduced a series of computational methods, three original research publications are presented in which the methods are applied in practice. Amongst many findings, the experimentally observed growth of Cu-S nanoplatelets on MoS2 was linked to the surface interactions with the ethylene glycol solvent. An extensive set of γ-PC/WS2 bilayer configurations was assessed, revealing property dependencies on the twist-angle and internal strains. Furthermore, a complex LaZr16S32/Co14Ni14O45(OH)11 nanostructure was deduced, for which an elaborate combination of DFT based material properties suggests excellent photocatalytic performance.
Created 29.4.2026 | Updated 30.4.2026