Novel catalytic functions induced by charge accumulation at subnano interface between unisize metal cluster disk and semiconductor surface

Abstract

We have successfully accumulated electrons in a subnano‐space according to the Schottky barrier junction between a subnano metal cluster and a semiconductor surface. The scanning–tunneling microscopy/spectroscopy measurements depicted spatial distributions of the accumulated charges. Taking advantages of their large charge‐transfer efficiency to molecules, novel catalytic functions driven by the subnano‐space charges were studied by means of ultrahigh‐sensitive temperature‐programmed desorption mass spectroscopy. As a representative function, we have found high‐performance catalytic activity of Pt30 monatomic‐layered disks constructed on the Si(111) surface in CO oxidation. Copyright © 2014 John Wiley & Sons, Ltd.

Size Dependence of Low-Temperature Catalytic Activity of CO Oxidation Driven by Platinum Clusters Directly Bound to Silicon Substrate Surface

“…Assignment and Deconvolution of TPD Spectra. Due to the good reproducibility of the TPD spectra between the present and previous 22,23 studies, the reaction mechanism and the peak assignment are managed in the same manner as in the previous study in comparison with the standard interpretation on the CO oxidation on a single-crystal Pt(111) surface. 25,33 The sharp peak at ∼120−130 K observed .…”

Bifunctional Property of Size-Selected Platinum Cluster Bound to Silicon Substrate in Low-Temperature Electron-Donation Catalysis for CO Oxidation

“…The details have been described in our previous reports, ,− ,− and this paper gives description relating to the present study. The experimental apparatus consists of a cluster-ion source, a charge separator, a mass filter for the size selection of the cluster ions, a cluster-impact device for the cluster deposition, and a surface-chemistry device .…”

“…One can promote these advantages also by tuning interaction between the subnano cluster and its supporting materials, which becomes dominant and sensitive against the number of the constituent atoms (cluster size) in a small size range, because of the larger contribution of the cluster-support interface as well. Therefore, it is inevitable to investigate size-dependent catalytic properties of the supported subnano clusters for finding and developing novel catalysts, and indeed, many studies have been reported so far. − …”

“…The electron accumulation of Pt N /Si brings high catalytic performance of the CO oxidation ,− owing to enhancing reductive splitting of O 2 to O as an active oxidation reagent through electron transfer from Pt N /Si to the antibonding molecular orbitals of O 2 . It has been demonstrated that this catalyst possesses ultralow-temperature activity of the electron donation; CO 2 is produced at 140 K, , which is ∼150 K lower than that for the bulk Pt(111) surface, after sequential supply of O 2 followed by CO to Pt N /Si.…”

“…It has been demonstrated that this catalyst possesses ultralow-temperature activity of the electron donation; CO 2 is produced at 140 K, , which is ∼150 K lower than that for the bulk Pt(111) surface, after sequential supply of O 2 followed by CO to Pt N /Si. This high-performance catalysis is also durable against repeated heating/cooling cycles in the range of 95–650 K in the reactive gases. ,− …”