Contriving a Catalytically Active Structure from an Inert Conformation

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Contriving a Catalytically Active Structure from an Inert Conformation: A Density Functional Investigation of Al, Hf, and Ge Doping of Au20 Tetrahedral Clusters Dar Manzoor,*,† Sailaja Krishnamurty,‡ and Sourav Pal*,§ †

Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630 006, India § Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India ‡

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ABSTRACT: The transformation of an inert structure into a catalytically active conformation has immense potential from a structural engineering point of view. In the present work, we explored methods of achieving such a transformation through a density-functional-based study. Au20 is known be one of the most stable and catalytically inert gold clusters, with a wellknown tetrahedral structure. We demonstrate the transformation of the inert Au20 conformation into a highly active catalytic cluster through selective doping with Hf and Ge atoms. Depending on the dopant, the inert tetrahedral Au20 cluster evolves into either an endohedral or a hollow-cage-like conformation. The structural changes are manifested in the catalytic properties as well, with the result that the transformed doped cages exhibit extremely low activation barriers for the environmentally important CO oxidation reaction as compared to reported inert Au20 cluster. The activation barriers for CO oxidation are particularly low (