In surface science there is great effort to move from studying simple, flat model surfaces in vacuum to investigating more complex model catalysts in gas environments (in situ). This thesis gives... Show moreIn surface science there is great effort to move from studying simple, flat model surfaces in vacuum to investigating more complex model catalysts in gas environments (in situ). This thesis gives three examples of such studies using microscopy and spectroscopy.Exposure of ZnO(10-10) to moderate pressures of water in an in situ scanning tunneling microscope reveals that the surface roughens. The flat ZnO(10-10) is thus only conditionally suited as a model catalyst for reactions involving water.In the same microscope, surface gold oxide formation is observed on TiO2/Au(111) during CO oxidation at 1 bar pressure. Comparisons to the Au(111) surface suggest that the titania does not supply atomic oxygen to the Au(111) substrate as part of the reaction mechanism of the CO oxidation.Co(0001) is investigated as a model catalyst for Fischer-Tropsch synthesis, the reaction of CO and H2 to form hydrocarbons. In this thesis the oxidation behavior of the cobalt and the adsorption of carbon species during the reaction are investigated using near-ambient pressure X-ray photoelectron spectroscopy.Generally, this thesis exemplifies the significant influence that small concentrations of contaminants in gases and materials can have on the structure and behavior of surfaces in in situ studies. Show less
Claes, L.M.G.F.E.; Groot, T. de; Huisman, H.; Kort, J.W. de; Os, B. van 2021
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
Weerd, M. van; Gatan-Balbas, M.; Hagen, R.; Servitillo, J. 2017
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course. Show less
In this study we focused on the simulation of the interaction of water and its dissociation products hydrogen, oxygen and OH with platinum surfaces that contain a periodic arrangement of single... Show moreIn this study we focused on the simulation of the interaction of water and its dissociation products hydrogen, oxygen and OH with platinum surfaces that contain a periodic arrangement of single-atom-high steps. We simulate these interactions using the framework of density functional theory and employ high-performance computing resources such as the Cartesius supercomputer of SURFsara. We find that the two possible types of step edges exhibit increased binding strengths compared to the flat parts of the interface. This binding strength is a key factor in the chemical reactivity of these surfaces. Furthermore, we investigate the structure of higher coverages of water molecules around the step edges, where we observe surprising changes, namely the appearance of four, five and seven-membered rings, compared to the six-membered rings that are usually observed on the flat surfaces. Our predictions for these structures are confirmed using high-resolution scanning tunneling microscopy data. Our results are among the first simulations of high-coverage water adsorption on regularly stepped platinum surfaces, which will help advance our understanding of solvation effects at the step edges, which are relevant for the fields of solvation science, electrochemistry and surface science. Show less
Weerd, M. van; Taggueg, J.; Luning, S.; Gatan-Balbas, M.; Servitillo, J.; Persoon, G. 2016
Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in... Show moreSince 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course Show less
As nickel and platinum are in the same group of the periodic table, the Ni(111) and Pt(111) surfaces may be expected to show similar interaction with water and hydrogen. However in this thesis, we... Show moreAs nickel and platinum are in the same group of the periodic table, the Ni(111) and Pt(111) surfaces may be expected to show similar interaction with water and hydrogen. However in this thesis, we show these interactions for Ni(111) are quite different from those of Pt(111). Moreover, our results show that the Ni(111) surface is a unique surface with regards to its chemistry of water and hydrogen. Show less
The thesis "Light-induced molecular processes on ice" deals with two main issues: first, the interaction of water with a platinum surface, under very well-defined conditions (at liquid nitrogen... Show moreThe thesis "Light-induced molecular processes on ice" deals with two main issues: first, the interaction of water with a platinum surface, under very well-defined conditions (at liquid nitrogen temperature in a very low-pressure environment (Ultra-High Vacuum: pressure 2 x 10-11 mbar)), and second, the photochemistry of small, naturally occurring, organic molecules such as bromoform (CHBr3) molecules on ice surfaces. The first topic is of relevance for electrochemistry, where water-metal interactions are crucial in determining the system's reactivity. The second topic is relevant for our understanding of processes encountered in the Earth's atmosphere. In particular, for atmospheric chemistry, the fundamental steps of the photochemical reaction of bromoform on ice surfaces induced by UV light, are elucidated. This reaction constitutes an important step in the ozone depletion cycle, which greatly affects our atmosphere. Photodissociation studies reveal a rich UV-induced photochemistry of bromoform on ice: various direct fragmentation pathways, as well as formation of new, ice-mediated C—C and C—O bond containing chemical species. Given the previously reported detection of bromoform in the stratosphere, these observations may have significant implications for current models describing stratospheric ozone depletion. Show less