Robust gold-decorated silica-titania pebbles for low-temperature CO catalytic oxidation

Suo Hon Lim, Nopphawan Phonthammachai, Ziyi Zhong, Jaclyn Teo, T. J. White

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

A deposition-precipitation (DP) process was used to prepare silica-titania core-shell pebbles decorated with nanocrystalline gold suitable for low-temperature catalytic oxidation of carbon monoxide (CO). The microstructure, phase content, crystallography, and catalytic activity were correlated with the pH (3-8), aging time (15,30,60 min), and heat treatment employed for gold crystallization (200-400°C). A homogeneous metal distribution, high gold loading (3.7-4.4 wt %), and superior interfacial adhesion between gold and titania were obtained when the support pebbles were prepared at 600°C, a temperature lower than that required for the anatase-to-rutile transformation. Nucleation and growth of {111} faceted gold was favored at mid-pH (6.4-8), while smaller crystals (<7.5 nm) were obtained at short aging times (≤60 min) and low growth temperatures (≤300°C). Catalytic activity was optimized by homogeneously dispersing gold nanocrystals (3 nm) using pH 6.4 and an aging time of 30 min. These robust materials may offer superior activity and lifetimes when deployed in fluidized bed catalytic cracking units.

Original languageEnglish
Pages (from-to)9480-9486
Number of pages7
JournalLangmuir
Volume25
Issue number16
DOIs
StatePublished - 18 Aug 2009
Externally publishedYes

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