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Metal Nanoclusters in Zeolite Nanocages: Synthesis and Characterization by X-Ray Photoelectron Spectroscopy
Bastl, Zdeněk ; Spirovová, Ilona
Rhodium and palladium nanoparticles were prepared in zeolites X and Y from ion exchanged metal ammine complexes by thermal decomposition of the complexes. X-ray photoelectron spectroscopy was employed to characterize individual steps of decomposition and growth of metal nanoparticles. Substantial reduction of Pd-tetraammine complex in zeolites by X-ray irradiation leading to inward diffusion of Pd and production of highly dispersed metal has been observed. Autoreduction by heating up to 400 oC resulted in significant decrease of Rh surface concentration and less pronounced decrease of Pd surface concentration. The Pd metal autoreduction occured readily in Y zeolite yielding small nanoclusters of Pd. The shifts of the core level binding energy of metal 3d electrons observed for thermally reduced metals in zeolites were consistent with presence of highly dispersed Rh metal and/or Rh+ and indicated interaction of Pd nanoparticles with zeolite matrix.
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Comparison of Meniscus (m-AgSAE), Film (MF-AgSAE) and Polished (p-AgSAE) Amalgam Electrodes
Fadrná, Renata
Silver solid amalgam electrode (AgSAE) is a suitable alternative to hanging mercury drop electrode (HMDE). There exist three types of AgSAE varying in different surfaces: meniscus modified (m-AgSAE), film (MF-AgSAE) and polished (p-AgSAE) electrode, which does not contain any liquid mercury. This work presents the comparison of the process and time heftiness of the electrodes pre-treatment and their electrochemical properties.
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