Electrically Induced Manipulation of the Au Nanoclusters on the Oxidized Rutile TiO₂(110) Surface by Atomic Force Microscopy at 78 K

Noble metal nanoclusters supported on a transition metal oxide surface are always regarded as the prototypical catalysts, and the controllable manipulation of the metal catalysts provides an efficient way to deliberately control the catalytic reactions, which still remains an experimental challenge thus far, possibly because of their nanometer-scale size and complex geometry. In this study, we report an electrically induced controllable manipulation of the Au nanoclusters on the oxidized rutile TiO2(110)-(1 × 1) surface by atomic force microscopy at 78 K. We demonstrate that, by applying the positive and negative voltage pulse beside the Au nanocluster, the target Au nanocluster can be laterally displaced on the oxidized rutile TiO2(110) surface. In addition, by applying the voltage pulse precisely on top of the Au nanoclusters, the reversible structural fluxionality of the Au nanoclusters between hemispherical and double-peak configurations is experimentally demonstrated for the first time, without any unexpected lateral/vertical manipulation or charge state transition. We propose that such a kind of controllable geometric manipulation of the Au nanoclusters is dominantly attributed to the tip-induced local electric field, which can be effectively tuned by controlling the tip site, magnitude, and polarity of the applied voltage pulse. Our study provides a pioneering work about the electrically induced manipulation of the nanometer-scale noble metal clusters on transition metal oxides, and can be potentially applied to deliberately control the catalytic reactions based on noble metal catalysts.