Solving the Structure of Size-Selected Pt Nanocatalysts Synthesized by Inverse Micelle Encapsulation

• DOI: 10.1021/ja101997z
• Publication Date: 2010-06-07T14:39:57Z
• Authors: Beatriz Roldan Cu...; Jason R. Croy; Simon Mostafa; Farzad Behafarid; Long Li; Zhongfan Zhang; Judith C. Yang; Qi Wang; Anatoly I. Frenkel
• Keywords: SUPPORTED METAL NANOPARTICLES; Multidisciplinary; ENVIRONMENTAL ELECTRON-MICROSCOPY; L-EDGE; RAY-ABSORPTION-SPECTROSCOPY; 01 natural sciences; XANES; 0104 chemical sciences; Chemistry; ATOMIC-SCALE; SHAPE; DEPENDENT CATALYTIC-ACTIVITY; PLATINUM NANOPARTICLES; COLLOIDAL SOLUTION; FINE-STRUCTURE

The structure, size, and shape of gamma-Al(2)O(3)-supported Pt nanoparticles (NPs) synthesized by inverse micelle encapsulation have been resolved via a synergistic combination of imaging and spectroscopic tools. It is shown that this synthesis method leads to 3D NP shapes even for subnanometer clusters, in contrast to the raft-like structures obtained for the same systems via traditional deposition-precipitation methods. Furthermore, a high degree of atomic ordering is observed for the micellar NPs in H(2) atmosphere at all sizes studied, possibly due to H-induced surface reconstruction in these high surface area clusters. Our findings demonstrate that the influence of NP/support interactions on NP structure can be diminished in favor of NP/adsorbate interactions when NP catalysts are prepared by micelle encapsulation methods.