Hydrogen isotope dynamic effects on partially reduced paramagnetic six-atom Ag clusters in low-symmetry cage of zeolite A

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• 作者：Amgalanbaatar Baldansuren¹ ; ^{amgalanbaatar.baldansuren@manchester.ac.uk}
• 关键词：Reduced Ag clusters ; H/D isotope exchange and desorption ; EPR ; HYSCORE ; Zeolite A
• 刊名：Progress in Natural Science: Materials International
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：26
• 期：6
• 页码：540-545
• 全文大小：699 K
• 卷排序：26

文摘

A well-defined, monodisperse Ag6+ cluster was prepared by mild chemical treatments including aqueous ion-exchange, dehydration, oxygen calcination at 673 K and hydrogen reduction 293 K, rather than autoreduction and irradiations with γ-ray and X-ray. H2 reduction was proved as a crucial step to form the nanosize cluster with six equivalent silver atoms. Hydrogen isotope exchange and dynamics were probed by EPR and HYSCORE to provide information relevant to the cluster geometry, size, charge state and spin state. Desorption experiments result in the deuterium desorption energy of 0.78 eV from the cluster, exceeding the experimental value of 0.38 eV for the single crystal Ag(111) surface. These experiments indicate that the EPR-active clusters are in delicate equilibrium with EPR-silent clusters.