Encapsulation of atomically thin gold nanosheets within porous silica for enhanced structural stability and superior catalytic performance

Atomically thin gold nanosheets (AuNSs) are fascinating two-dimensional (2D) nanomaterials with distinctive physicochemical properties arising from their ultrathin structure. However, the limited structural stability of these atomically thin AuNSs significantly hinders their practical applications....

Full description

Saved in:
Bibliographic Details
Published inNew journal of chemistry Vol. 46; no. 39; pp. 18699 - 1879
Main Authors Balakrishnan, Thiruparasakthi, Choi, Sung-Min
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 10.10.2022
Subjects
Catalytic activity
Chemical reduction
Encapsulation
Gold
Nanomaterials
Nanosheets
Nanostructure
Nitrophenol
Polyethylene glycol
Silicon dioxide
Structural stability
Tetraethyl orthosilicate
Thickness
Thin films
Online AccessGet full text

Cover

More Information
Summary:Atomically thin gold nanosheets (AuNSs) are fascinating two-dimensional (2D) nanomaterials with distinctive physicochemical properties arising from their ultrathin structure. However, the limited structural stability of these atomically thin AuNSs significantly hinders their practical applications. Here, we report the fabrication of atomically thin AuNSs (two atomic layers thick) encapsulated within a uniform porous silica layer (AuNS@pSiO 2 ), which show excellent structural stability in dried powder form and superior catalytic activity and stability for the reduction of 4-nitrophenol (4-NPh). For this, the synthesized atomically thin AuNSs are functionalized with thiolated poly(ethylene glycol) (SH-PEG) followed by encapsulation in silica layers of different thicknesses using different amounts of tetraethyl orthosilicate. The UV-ozone treatment removes the PEG molecules within the silica layers to form AuNS@pSiO 2 . The AuNS@pSiO 2 shows structural stability in dried powder form while the as-prepared AuNSs aggregate and merge immediately after being dried into a powder. The AuNS@pSiO 2 exhibits superior catalytic activity with a normalized rate constant of 8.8 × 10 4 min −1 g Au −1 compared to the previously reported porous silica-encapsulated gold nanostructures for the 4-NPh reduction reaction. In addition, the AuNS@pSiO 2 shows excellent catalytic stability compared to the as-prepared AuNSs during the reusability test at 60 °C. The enhanced structural and catalytic stability of the atomically thin AuNSs could be due to the porous silica layer on their surface. Porous silica-encapsulated atomically thin AuNSs exhibit excellent structural stability in dried state and superior catalytic activity and stability for the reduction of 4-nitrophenol.
Bibliography:0
ca.
Electronic supplementary information (ESI) available: UV-Vis absorption spectrum, TEM image, SAED pattern, AFM, and DLS analysis of the as-prepared AuNSs; TEM images of AuNSs in the dried state; TEM image and TGA of AuNSs functionalized with SHPEG; distribution of silica layer thickness; TEM image and elemental analysis of AuNSs encapsulated with
6.3 nm thick silica layers, respectively; TEM images of as-prepared AuNS dispersions and dried isolated as-prepared AuNSs treated at different temperatures; photographs of 4-NPh solution before and after catalytic reaction; UV-vis absorption spectra monitoring the 4-NPh reduction at different temperatures with time and the corresponding plot of ln
C
against reaction time. See DOI
t
3.4 and
/
https://doi.org/10.1039/d2nj03221j
ISSN:1144-0546
1369-9261
DOI:10.1039/d2nj03221j