Date/Time
27.11.2025
2:00 pm – 3:00 pm
Location
Lecture Hall 55.02
Pfaffenwaldring 55
70569 Stuttgart
We are very happy to welcome within the CRC 1333 Colloquium Series:
Thursday, November 27, 2025, 2:00-3:00 pm
Fritz Haber Institute of the Max Planck Society
Topic: “Creation of Functional Interfaces from Oxide Precursors via Exsolution Strategies“
Her work is devoted to the investigation of metal oxides for activation of C-H, O-O, and C-O bonds. The oxidation of short-chain alkanes and oxygenates on the surface of bulk and supported V-based mixed oxides, perovskites, and alkaline earth metal oxides is studied with the aim to identify descriptors to predict selectivity. In the field of CO and CO2 activation, the influence of transi metal oxide promoters on the reactivity of metal nano -particles is investigated.
Abstract:
The design of functional interfaces remains a key challenge in developing active and selective heterogeneous catalysts. Exsolving metal species from well-defined crystalline oxide precursors offers a robust synthetic approach. The generated metal nanoparticles are confined at the surface of the host matrix, which ensures a strong metal-support interaction and prevents sintering at high temperatures. To maximize the number of active sites, the exsolution process should be carried out at the lowest possible temperature. One way to achieve this is to synthesize the host oxide with small primary particles. In our work, we use spray-flame synthesis and hydrothermal techniques, including continuous-flow hydrothermal synthesis under supercritical conditions. Exsolution-decomposition strategies are employed for both low- and high-temperature catalytic reactions in thermal catalysis, such as the ammonia decomposition and C-C coupling reactions starting from CO and CO2.
The presentation will focus on the synthesis of heterogeneous ZnFe2O4-supported rhodium catalysts for olefin hydroformylation at the solid–liquid interface via low-temperature exsolution from spinel precursors. In the chemical industry, this reaction, typically performed with homogeneous catalysts, is a major route to aldehydes. Metal leaching in liquid-phase reactions remains an unsolved challenge, hindering the application of supported nanoparticles that could emulate the activity of homogeneous systems.
Phase purity of the precursor, isomorphic substitution of the active noble metal into the host oxide structure and the exsolution process were studied by complementary experimental techniques and theory. Infrared spectroscopy of adsorbed probe molecules allowed insight into the electronic nature of the active metal. Compared to impregnated Rh, exsolved Rh particles exhibit stronger metal–hydride and weaker metal–carbonyl interactions, favoring aldehyde formation over olefin isomerization in the hydroformylation of 1-hexene without leaching.
This example demonstrates the importance of developing advanced synthetic concepts for the rational design of catalysts.
The CRC cordially invites all who are interested to the lecture.