1. Development of the Pair Distribution Function Technique to Study the Nucleation and Growth Mechanism of Supported Metals
María M. Martínez-Iñesta, University of Puerto Rico
The structural changes that a metal precursor incurs during nucleation and growth into metal clusters are very difficult to observe using regular crystallographic characterization techniques. With the pair distribution function we can observe changes in the interatomic distances at the angstrom scale during oxidation and reduction which we can use to model its growth. With this information it is possible to better understand how the different reaction steps affect the final dispersion of the metal clusters and the structural changes that concurrently occur in the support.
Zeolite support
Dry impregnated 1.5%Pt 1°C/min
Ion exchanged 1.5% Pt 0.2°C/min
Ion exchanged 1.5% Pt 1°C/min
Ion exchanged 2.5% Pt 1°C/min
r (Å)
Zeolite support
Dry impregnated 1.5%Pt 1°C/min
Ion exchanged 1.5% Pt 0.2°C/min
Ion exchanged 1.5% Pt 1°C/min
Ion exchanged 2.5% Pt 1°C/min
r (Å)
Interatomic distance changes after oxidation at different synthesis conditions
Interatomic distance changes after reduction at different synthesis conditions