Reversible Switching of Catalytic Activity by Shuttling an Atom into and out of Gold Nanoclusters. 
It is challenging to control the catalyst activation and deactivation by removal and addition of only one central atom, as it is almost impossible to precisely abstract an atom from a conventional catalyst and analyze its catalysis.  Here we report that the loss of one central atom in Au25 (resulting in Au24 ) enhances the catalytic activity in the oxidation of methane compared to the original Au25 .  More importantly, the activity can be readily switched through shuttling the central atom into Au24 and out of Au25 .  This work will serve as a starting point for design rules on how to control catalytic performance of a catalyst by an atom alteration.