Ball-Milling Mechanochemistry at the Molecular Level-2

Projektbeschreibung

Mehr Wissen über Mechanochemie

Die Mechanochemie des Kugelmahlens hat in den letzten Jahren revolutionäre Fortschritte durchlaufen, die in einer Vielzahl von Lösungen und Verfahren Anwendung finden. Die Forschenden, die sein Potenzial erforschten, konnten es für katalytische Reaktionen einsetzen, darunter die katalytische Ammoniaksynthese aus H2 und N2 bei Raumtemperatur und Atmosphärendruck. Leider fehlen uns ungeachtet dieses Erfolgs immer noch wichtige Erkenntnisse über die molekularen Prozesse, die der mechanischen Aktivierung zugrunde liegen. Das Ziel des vom Europäischen Forschungsrat finanzierten Projekts BM3L-2 lautet, mehrere relevante Hypothesen auf atomarer Ebene zu untersuchen, um wichtige Erkenntnisse zu gewinnen, die Licht in die den wichtigsten mechanochemischen Reaktionen zugrunde liegenden Prozesse bringen, und letztlich die Mechanochemie und unser Verständnis davon voranzubringen.

Ziel

Ball milling mechanochemistry is receiving tremendous attention over the last years. The applicant has pioneered the use of it for effecting catalytic reactions, culminating in catalytic ammonia synthesis from H2 and N2 at room temperature and atmospheric pressure. In spite of the success in driving reactions mechanically, the molecular level understanding of the key processes under mechanical activation is still in its infancy. The proposed program will change this, using methods giving insight at the atomic scale. By a multi-pronged approach, the applicant – partly in collaborations - will experimentally probe at the atomic scale hypotheses, which have been put forward to explain the special effects of mechanochemical reactions, to provide key elements for a conceptual understanding.
Three topical areas will be covered, in addition, one general purpose tool for the study of mechanochemical reactions will be developed. (1) Temperature dependent luminescence will be used to monitor temperatures during model impacts in order to probe the hot spot and magma/plasma hypotheses. (2) The role of hypothetical, short-lived, mechanically induced defects in catalysis will be analyzed locally at the atomic scale in scanning probe microscopes. (3) In order to understand mechanically induced phase transitions, mechanical forces will be applied in-situ to precursor crystals in a transmission electron microscope (TEM), and phase transitions, for instance from boehmite to corundum, will be followed at the atomic scale by TEM imaging. (4) As a general tool to study the influence of mechanical forces, a hammer/anvil system will be developed in which directly after applying mechanical force the system can be studied by various analytical methods. Overall, the program is expected to provide deep mechanistic understanding of different aspects of mechanochemistry to advance it to a next level.