Recent Research Highlights


	Details of the Real Structure of Cd_xNb₆(O,F)₁₆ The structure of Cd_xNb₆(O,F)₁₆ crystallizes in the orthorhombic LiNb₆O₁₅F structure type (space group Pmma). Light microscopy and scanning electron microscopy imaging reveals a frequent intergrowth of crystallites on the micrometer scale while HAADF-STEM images show perfect order in most areas. However, a single grain boundary was found with the structures in the adjacent domains tilted by 4° in respect of each other (see image). The adjacent domains are coherently connected in parts of the interface but frequently defects occur at irregular intervals. A Detailed Structural Analysis of Cd_xNb₆(O,F)₁₆ F. Krumeich and M. Wörle Z. anorg. allgem. Chem. 2019, 645, 753–757, DOI		HAADF-STEM image showing the defective area (red) between the well-ordered domain (blue and green). The structures in both domains are tilted by ca. 4° in respect of each other.
	Catalyst Deactivation in Fluid Catalytic Cracking Fluid catalytic cracking (FCC), an important process in chemical industry, converts the heavy fractions of crude oil into valuable petrol and chemicals. The catalyst is a spherical composite of zeolite and clay that decreases in catalytic activity during long-term operation. By using a range of electron microscopy and elemental mapping techniques, the structural and chemical characteristics of pristine and progressively deactivated catalyst particles have been characterized from the micro- down to the nanometer scale. An increasingly dense amorphous silica alumina layer wrapping the particles is formed during operation. Fe and Ca are the main impurities in this envelope. A three-dimensional view of structural changes caused by deactivation of fluid catalytic cracking catalysts J. Ihli, R. R. Jacob, M. Holler, M. Guizar Sicairos, A. Diaz, J. C. da Silva, D. Ferreira Sanchez, F. Krumeich, D. Grolimund, M. Taddei, W.-C. Cheng, Y. Y. Shu, A. Menzel, and J. A. van Bokhoven Nature Commun. 2017, 8, 809, DOI Localization and Speciation of Iron Impurities within a Fluid Catalytic Cracking Catalyst J. Ihli, D. Ferreira Sanchez, J. Rosh, V. Cuartero, O. Mathon, F. Krumeich, C. Borca, T. Huthwelker, W.-C. Cheng, Y.-Y. Shu, S. Pascarelli, D. Grolimund, A. Menzel, and J. A. van Bokhoven Angew. Chem. Int. Ed. 2017, 56, 14031-14035, DOI Structural changes in deactivated fluid catalytic cracking catalysts determined by electron microscopy F. Krumeich, J. Ihli, Y.Y. Shu, W.-C. Cheng, and J. A. van Bokhoven ACS Catal. 2018, 8, 4591–459, DOI		Scheme demonstrating the EM methods used to explore the structure and chemistry of FCC particles and their cross-sections at different length scales.
	Luminescent Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica By soaking mesoporous silica with perovskite precursor solutions followed by drying, lead halide perovskite nanocrystals are formed inside the silica pores (Figure: HAADF-STEM image of a SiO₂ sample with 7 nm pores partially filled with CsPbI₃ nanoparticles). This material shows very bright photoluminescence (inset). Harnessing Defect-Tolerance at the Nanoscale: Highly Luminescent Lead Halide Perovskite Nanocrystals in Mesoporous Silica Matrices D. N. Dirin, L. Protesescu, D. Trummer, I. V. Kochetygov, S. Yakunin, F. Krumeich, N. P. Stadie, and M. V. Kovalenko Nano Letters 16 (2016) 5866−5874, DOI		In-Situ Heating of Carbon-Coated LiFePO₄ The thermal behavior of core-shell carbon-coated LiFePO₄ nanoparticles, a promising battery material made by flame spray pyrolysis, during annealing was investigated by in-situ TEM. At a temperature of T = 700 °C, LiFePO₄ starts to diffuse through the carbon shell resulting in cavities inside the mostly intact carbon shell. By increasing the temperature to T = 800 °C, the initial core-shell morphology is converted into open carbon shells and bulky LiFePO₄ particles. *Thermal Annealing Dynamics of Carbon-Coated LiFePO₄ Nanoparticles Studied by In-Situ* Analysis F. Krumeich, O. Waser, and S. E. Pratsinis J. Solid State Chem. 242** (2016) 96–102, DOI
	Archive 2015 Functionalized BN / Hollow Zeolites 2014 Single Atoms in Catalysts / Imaging Li in LiBC 2013 Phase Contrast in STEM / Tin Nanocrystals for Battery Applications 2012 Dodecagonal Quasicrystals / Behaviour of Nanoparticles in a Waste Incineration Plant 2011 Catalyst Characterization / Coated Nanoparticles / Optimization of Catalysts 2010 Cation Ordering in Perovskites / Leaching of ZSM-5 Zeolithes Cytoxicity of Nanoparticles / Structure Determination of Bi₆S₂O₁₅
	Publication lists: orcid.org/0000-0001-5625-1536 ----- Scopus author

ETH Zürich | ETH chemistry department | ETH inorganic chemistry