Insights into Palladium Deactivation during Advanced Oxidation Processes

Identifier:  imarina:9282894

Handle: https://hdl.handle.net/20.500.11797/imarina9282894

Authors:  Pinos-Vélez, V; Osegueda, O; Crivoi, DG; Llorca, J; Alvarez, MG; Medina, F; Dafinov, A; García-García, FJ

Abstract:
A key step in creating efficient and long-lasting catalysts is understanding their deactivation mechanism(s). On this basis, the behavior of a series of Pd/corundum materials during several hydrogen adsorption/desorption cycles was studied using temperature-programmed desorption coupled with mass spectrometry and aberration-corrected transmission electron microscopy. The materials, prepared by impregnation and by sputtering, presented uniform well-dispersed Pd nanoparticles. In addition, single atoms and small clusters of Pd were only detected in the materials prepared by impregnation. Upon exposure to hydrogen, the Pd nanoparticles smaller than 2 nm and the single atoms did not present any change, while the larger ones presented a core-shell morphology, where the core was Pd and the shell was PdHx. The results suggest that the long-term activity of the materials prepared by impregnation can be attributed solely to the presence of small clusters and single atoms of Pd.