highlights

Cryo STEM

Many material are sensitive to the electron beam and undergone modifications during the TEM and STEM investigation. A means to minimize this unwanted effect is cooling the sample with liquid nitrogen. This procedure has recently been utilized to image various perovskite lead halides by HAADF-STEM avoiding the usual decompositition and formation of lead nanoparticles.

Stable Ultra-Concentrated and Ultra-Dilute Colloids of CsPbX₃ (X = Cl, Br) Nanocrystals using Natural Lecithin as a Capping Ligand
F. Krieg, Q. K. Ong, M. Burian, G. Rainò, D. Naumenko, H. Amenitsch, A. Süess, M. Grotevent, F. Krumeich, M. I. Bodnarchuk, I. Shorubalko, F. Stellacci, and M. V. Kovalenko
J. Am. Chem. Soc. 2019, 141, 19839-19849 DOI

Scalable Photonic Sources Using Two-Dimensional Lead Halide Perovskite Superlattices
J. Jagielski, S. F. Solari, L. Jordan, D. Scullion, B. Blülle, Y.-T. Li, F. Krumeich, Y.-C. Chiu, B. Ruhstaller, E. J. G. Santos, and C.-J. Shih
Nature Commun. 2020, 11, 387 DOI

HAADF-STEM image of CsPbBr₃ nanocrystals obtained at cryogenic conditions.

Cover and HAADF-STEM image of single Pt atoms (bright spots) on the carbon support.

Single atom catalysis

Single metal atom are becoming increasingly important in heterogeneous catalysis as every atom might be efficient in a process. The fixation on a suitable host material that firmly anchors the metal atoms reduces their tendency to aggregate and sinter. An example are Pt atoms on carboneous materials that are stable catalyst for the industrially important synthesis of vinyl chloride.

Tailoring Nitrogen-Doped Carbons as Hosts for Single-Atom Catalysts
S. Büchele, Z. Chen, S. Mitchell, R. Hauert, F. Krumeich, and J. Pérez‑Ramírez
ChemCatChem 2019, 11, 2812-2820 DOI

Tunability and Scalability of Single-Atom Catalysts Based on Carbon Nitrides
Z. Chen, S. Mitchell, F. Krumeich, R. Hauert, S. Yakunin, M. V. Kovalenko, and J. Pérez-Ramírez, ACS Sustainable Chem. Eng. 2019, 7, 5223–5230 DOI

Nanostructuring unlocks high performance of platinum single-atom catalysts for stable vinyl chloride poduction
S. K. Kaiser, E. Fako, G. Manzocchi, F. Krumeich, R. Hauert, A. Clark, O. V. Safonova, N. López, and Javier Pérez-Ramírez, Nature Catal. 2020, 3, 376–385 DOI

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.

Archive

2018
FCC catalysts

2016
Luminescent CsPbI₃ nanoparticles/ C-coated FePO₄

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 iD icon orcid.org/0000-0001-5625-1536 ----- Scopus author

Recent Research Highlights