Following the temperature-induced activation of carbon-supported trigonal Pd₃ nanoclusters for catalysis

Abstract

The thermal activation of the nanoclusters on a support material can enhance their activity and selectivity in heterogeneous catalysis. However, their evolution upon thermal activation remains challenging to study due...

Probing the Formation and Evolution of Pd Nanoparticles on the Surface of γ-Al2O3 Using a Pd(II) Coordination Polymer as a Precursor: An In Situ X-ray Scattering and Spectroscopy Study

“…The oxidation of the Pd NPs on the surface of γ-Al 2 O 3 starts at 500 °C due to the phase transformation of Pd to PdO, and the complete phase transformation to PdO is not apparent until 720 °C. The phase transformation of supported Pd(0) to PdO usually occurs around 250 °C; ,, however, Pd oxidation is found to be quite slow for the Pd­(II)-CP@Al 2 O 3 sample, whereas rapid oxidation of Pd NPs was seen for the Pd­(II)-CP sample in the absence of γ-Al 2 O 3 . This seems to suggest that Pd NPs nucleating at the CP/Al 2 O 3 interface are still partially passivated by ligands from the CP, and only when these are completely removed does PdO begin to appear.…”

“…The in situ XAS spectra of Pd­(II)-CP and Pd­(II)-CP@Al 2 O 3 along with some standards are shown in Figure a,c. The XANES spectrum of the Pd­(II)-CP shows a sharp feature at the white line, which is also representative of the presence of Pd­(II); however, the peak for the zero-valent metal is much lower in that region (Pd foil) . The in situ XANES data were fitted through a linear combination fitting (LCF) approach to extract information about the speciation of the samples at different temperatures.…”

Evidence for Suzuki–Miyaura cross-couplings catalyzed by ligated Pd3-clusters: from cradle to grave

“…The results are complementary to those described here, and provide insight into how changes in the ‘Pd 3 Cl 2 ’ cluster can occur at significantly higher temperatures (between 150 and 250 °C). 41 …”