Thermally stable Pt/mesoporous silica core–shell nanocatalysts for high-temperature reactions

Abstract

Recent advances in colloidal synthesis enabled the precise control of the size, shape and composition of catalytic metal nanoparticles, enabling their use as model catalysts for systematic investigations of the atomic-scale properties affecting catalytic activity and selectivity. The organic capping agents stabilizing colloidal nanoparticles, however, often limit their application in high-temperature catalytic reactions. Here, we report the design of a high-temperature-stable model catalytic system that consists of a Pt metal core coated with a mesoporous silica shell (Pt@mSiO(2)). Inorganic silica shells encaged the Pt cores up to 750 degrees C in air and the mesopores providing direct access to the Pt core made the Pt@mSiO(2) nanoparticles as catalytically active as bare Pt metal for ethylene hydrogenation and CO oxidation. The high thermal stability of Pt@mSiO(2) nanoparticles enabled high-temperature CO oxidation studies, including ignition behaviour, which was not possible for bare Pt nanoparticles because of their deformation or aggregation. The results suggest that the Pt@mSiO(2) nanoparticles are excellent nanocatalytic systems for high-temperature catalytic reactions or surface chemical processes, and the design concept used in the Pt@mSiO(2) core-shell catalyst can be extended to other metal/metal oxide compositions.

Nanocatalysis I: Synthesis of Metal and Bimetallic Nanoparticles and Porous Oxides and Their Catalytic Reaction Studies

“…Joo et al developed a Pt/SiO 2 core/shell as a thermally stable catalyst, in which mesoporous silica shells encaged Pt cores and the Pt nanoparticles maintained their structure up to 750°C in air without aggregation (Fig. 3a) [25]. In order to allows access of reactants to the core metals, inorganic porous materials are selected as a protecting shell.…”

Co-Assembly of Nanoparticles in Evaporating Aerosol Droplets: Preparation of Nanoporous Pt/TiO2Composite Particles

“…Therefore, a great deal of work has been done in preparing new types of Pt nanomaterials such as shape controlled nanoparticles (Ahmadi et al 1996;Song et al 2004;Lee et al 2008;Peng and Yang 2009;Zhou et al 2009) and supported Pt nanoparticles (Teng et al 2003;Chupas et al 2007;Alonso et al 2008;Joo et al 2009;Shanmugam and Gedanken 2009a), motivated by the need for high catalytic activity. Reducing the consumption of Pt without sacrificing its catalytic performance is an important subject of research due to its high value and limited supply.…”

A copper-phyllosilicate core-sheath nanoreactor for carbon–oxygen hydrogenolysis reactions

“…However, these approaches are not generally applicable because they restrict chemical composition and functionality. Recently, the encapsulation of individual NPs in morphologically well-defined inorganic shells or tubes has received much attention because of the thermal and chemical stabilities in catalysis [12][13][14][15] .…”