High‐Temperature‐Stable and Regenerable Catalysts: Platinum Nanoparticles in Aligned Mesoporous Silica Wells. Issue 10 (22nd August 2013)

• Record Type: Journal Article
• Authors: Xiao, Chaoxian; Maligal‐Ganesh, Raghu V.; Li, Tao; Qi, Zhiyuan; Guo, Zhiyong; Brashler, Kyle T.; Goes, Shannon; Li, Xinle; Goh, Tian Wei; Winans, Randall E.; Huang, Wenyu
• Is Part Of: ChemSusChem. Volume 6:Issue 10(2013:Oct.)
• Page Start: 1915
• Page End: 1922
• Publication Date: 2013-08-22
• Subjects: Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201300524
• Languages: English
• ISSNs: 1864-5631

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>We report the synthesis, structural characterization, thermal stability study, and regeneration of nanostructured catalysts made of 2.9 nm Pt nanoparticles sandwiched between a 180 nm SiO<sub>2</sub> core and a mesoporous SiO<sub>2</sub> shell. The SiO<sub>2</sub> shell consists of 2.5 nm channels that are aligned perpendicular to the surface of the SiO<sub>2</sub> core. The nanostructure mimics Pt nanoparticles that sit in mesoporous SiO<sub>2</sub> wells (Pt@MSWs). By using synchrotron‐based small‐angle X‐ray scattering, we were able to prove the ordered structure of the aligned mesoporous shell. By using high‐temperature cyclohexane dehydrogenation as a model reaction, we found that the Pt@MSWs of different well depths showed stable activity at 500 °C after the induction period. Conversely, a control catalyst, SiO<sub>2</sub>‐sphere‐supported Pt nanoparticles without a mesoporous SiO<sub>2</sub> shell (Pt/SiO<sub>2</sub>), was deactivated. We deliberately deactivated the Pt@MSWs catalyst with a 50 nm deep well by using carbon deposition induced by a low H<sub>2</sub>/cyclohexane ratio. The deactivated Pt@MSWs catalyst was regenerated by calcination at 500 °C with 20 % O<sub>2</sub> balanced with He. After the regeneration treatments, the activity of the Pt@MSWs catalyst was fully restored. Our results suggest that the nanostructured catalysts—Pt nanoparticles confined inside mesoporous SiO<sub>2</sub> wells—are stable and regenerable for treatments and reactions that require high temperatures.</p> </abstract>