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- New article published: Nanometer-Resolved Operando Photo-Response of Faceted BiVO4 Semiconductor NanoparticlesPhoto(electro)catalysis with semiconducting nanoparticles (NPs) is an attractive approach to convert abundant but intermittent renewable electricity into stable chemical fuels. However, our understanding of the microscopic processes governing the performance of the materials has been hampered by the lack of operando characterization techniques with sufficient lateral resolution. Here, we demonstrate that the local surface potentials of NPs of bismuth vanadate (BiVO4) and their response to illumination differ between adjacent facets and depend strongly on the pH of the ambient electrolyte. The isoelectric points of the dominant {010} basal plane and the adjacent {110} side facets differ by 1.5 pH units. Upon illumination, both facets accumulate positive charges and display a maximum surface photoresponse of +55 mV, much stronger than reported in the literature for the surface photo voltage of BiVO4 NPs in air. High resolution images reveal the presence of numerous surface defects ranging from vacancies of a few atoms, to single unit cell steps, to microfacets of variable orientation and degree of disorder. These defects typically carry a highly localized negative surface charge density and display an opposite photoresponse compared to the adjacent facets. Strategies to model and optimize the performance of photocatalyst NPs, therefore, require an understanding of the distribution of surface defects, including the interaction with ambient electrolyte.Read more
- New article published: Elastometry of Complex Fluid Pendant CapsulesWhen a pendant drop of crude oil is aged in brine, it can form an interfacial elastic membrane of asphaltenes so stiff that it wrinkles and crumples upon retraction. In early retraction, the interface shows a fluid viscoelasticity measurable using a Gibbs Isotherm or dilatational rheology. Further retraction causes a phase transition to a 2D elastic solid with non-isotropic, non-homogeneous surface stresses. In this regime, we use new techniques in elastic membrane theory to fit for the elasticities of these solid capsules. These elastic measurements can help us develop a deeper understanding not only of crude oil interfaces, but also of the myriad fluid systems with solid interfacial layers.Read more
- Tue 16 Jan 2024New article published: Nanometer-Resolved Operando Photo-Response of Faceted BiVO4 Semiconductor Nanoparticles
- Thu 26 Oct 2023New article published: Elastometry of Complex Fluid Pendant Capsules
- Thu 26 Oct 2023New article published: Microfluidics for Carbonate Rock IOR: Some Lessons From Fabrication, Operation and Image Analysis (Review Paper)
- Wed 6 Sep 2023Energy transition: pure bio-gas from pilot with 'modified cat litter pellets'
- Tue 4 Jul 2023Congratulations Dr. Su !
- Tue 20 Jun 2023Thursday June 29, 13.30 hr, ZH 286, Colloquium Prof.dr. Angelika Kühnle, Professor of Physical Chemistry at Bielefeld University
- Wed 17 May 2023New article published: Non-equilibrium configurations of swelling polymer brush layers induced by spreading drops of weakly volatile oil
- Mon 27 Mar 2023Vacancy Technician
- Mon 20 Mar 2023Igor Siretanu et al. published an article in Faraday Discussions on hydration forces at the interface between electrolytes of variable composition and crystalline mica vs. amorphous silica
- Wed 15 Mar 2023Thursday March 23, 11.30 hrs, Zuidhorst ZH 286, Colloquium Assistant Prof. dr. Helen King from Utrecht University.
- Mon 13 Mar 2023New article published: Microfluidics for Carbonate Rock IOR: Some Lessons From Fabrication, Operation and Image Analysis (Conference Paper)
- Wed 15 Feb 2023Tuesday February 21, 11.00 hrs, ZH 286: Colloquium Dr. Csaba Forro (Postdoctoral Fellow with a joint appointment at Stanford University (USA) and Forschungszentrum Juelich (Germany)