Thermal stability of oxide-supported gold nanoparticles

Abstract

In this study, we report on the influence of support and gas atmosphere on the thermal stability of Au nanoparticles on oxidic supports. All samples were prepared with a modified impregnation method and have initial Au particle sizes in the range of 3-4 nm. We observed that in air, Au nanoparticles on SiO 2 and Al 2 O 3 are thermally much more stable than Au nanoparticles on TiO 2. For instance, upon treatment up to 700°C, on SiO 2 , Au particles grew from 4 to 6 nm while on TiO 2 from 3 to 13 nm. For Au nanoparticles on TiO 2 , growth is accelerated by oxidizing atmospheres and the presence of water and/or chloride. On nonreducible supports and in non-oxidizing atmosphere, the supported Au nanoparticles were remarkably stable. The insight into the growth of oxide-supported Au nanoparticles in reactive atmosphere offers an additional tool for a rational choice of a support for high-temperature gas-phase reactions involving gold nanocatalysts.

Structural and chemical evolution of Au-silica core–shell nanoparticles during 20 keV helium ion irradiation: a comparison between experiment and simulation

“…The silica shells appear to have coalesced together after the final fluence of 4.7 × 10 17 ions/cm 2 , also reducing the area of the silica-vacuum interface. Coalescence of nanoscale silica has been previously reported in in-situ TEM heating experiments 51,54,55 Our results show coalescence of silica can be induced by ion-irradiation.…”

Preparation and catalytic evaluation of Au/γ-Al2O3nanoparticles for the conversion of 4-nitrophenol to 4-aminophenol by spectrophotometric method

“…For example, thermal treatment of Au nanoparticles up to 700°C , on SiO 2 , let particles grow from 4 to 6 nm while on TiO 2 from 3 to 13 nm. Also, Al 2 O 3 provides a nonreducible support and a nonoxidizing atmosphere for stable supported Au nanoparticle [33]. To the best of our knowledge we obtained lowest effective nobel metal loading as compared to previous reports [33][34][35][36].…”

Nanomaterials: stimulants for biofuels and renewables, yield and energy optimization

“…Most of the metallic nanoparticles are stable up to 400 K but stability will increase beyond 800 K if metal nanoparticles supported over SiO2 or Al2O3. 42,43 The Carbon nanotubes (CNT) are stable temperatures above 3400 K. 44…”