Enhanced Immobilization of Gold Nanoclusters on Graphite

Abstract

The immobilization of individual biological molecules by metal nanoparticles requires that the particles themselves be immobilized. We introduce a new technique for immobilization of gold clusters based on their binding to small tunnels in a graphite support, themselves created by the implantation of small clusters. These tunnels are shown to perform as more effective cluster immobilization sites than point defects on the surface of graphite. The method is tested with atomic force microscopy (AFM) (both contact and noncontact mode) scanning. Size-selected clusters with 923, 561, 309, and 147 atoms have been immobilized and imaged with high-resolution, noncontact AFM.

Immobilization of Au nanoparticles on graphite tunnels through nanocapillarity

“…5, the height average for each particle is compared against the experimental results. 7 As expected, the average height increases with the NP size. For smaller nanopar- ticles an excellent agreement between simulated and experimental values is reached.…”

“…In order to successfully simulate the experiments reported by R. Palmer 7 , two processes have to be correctly described by the potential chosen: the physisorption and the chemisorption of gold nanoparticles on graphite. In the first case the cluster is interacting with a pristine layer of carbon atoms, while in the second case the nanoparticle is interacting with the carbon edges of the tunnel.…”

“…a Universidad Autónoma de Nuevlo León, San Nicolás de los Garza, N.L., Mexico 66455, * E-mail:sergio.mejiars@uanl.edu.mx b INFIQC -Departamento de Matemática y Física -Facultad de Ciencias Químicas Universidad Nacional de Córdoba, Argentina. Fax: +49 731 50 22819, Tel: +49 731 50 31340, * E-mail: marcelo.mariscal@unc.edu.ar Palmer et al 7 proposed a novel methodology which consists in bombarding small Au clusters on a highly oriented pyrolytic graphite (HOPG) surface. The clusters are generated by means of radio frequency magnetron sputtering and a gas condensation cluster source, combined with a lateral time-offlight (TOF) mass filter.…”

“…The number of graphite layers penetrated by the Au cluster and the amount of damage, may depend not only in the kinetic energy, but also on the shape and the relative orientation of the cluster with respect to the surface. In their experiments, Palmer 7 used clusters of 20 atoms in size (Au 20 ). As it is very well known, such a cluster has a tetrahedral structure, which is a fragment of the face-centered cubic lattice of bulk gold with a small structural relaxation.…”

Metal Clusters on Semiconductor Surfaces and Application in Catalysis with a Focus on Au and Ru

“…Both AFM and STM4d,7a,84,91,106a have been used in determining the geometric properties such as size and distribution of supported metal clusters. Both suffer from tip‐convolution effects due to the tip curvature, and the lateral resolution is often larger than the size of small clusters resulting in an overestimation of particle width 7a.…”