Thermal Hydrogen Reduction for Synthesis of Gold Nanoparticles in the Nanochannels of Mesoporous Silica Composite

Abstract

Gold nanoparticles (AuNPs) with small particle size have been difficult to be synthesized due to their strong agglomeration. Herein we report that the nanochannels of mesoporous silica synthesized from template sol-gel synthesis were utilized to prepare AuNPs by employing thermal hydrogen reduction. Mesoporous silica composite with an interpore distance of 4.1 nm was successfully fabricated as a thin film by an amphiphilic trinuclear gold(I) pyrazolate complex ([Au3Pz3]C10TEG) as a template. In contrast to calcination method of this composite and the bulk [Au3Pz3]C10TEG complex at 450ºC for 3 h, thermal hydrogen reduction at 250ºC for 2 h showed transmission electron microscope (TEM) images and diffraction pattern with smaller particle size (14.5 nm) and more homogenous distribution of AuNPs with up to 44% of the particle size in the range of 10 to 20 nm. The decreasing of average particle size in this new strategy indicated by the red-shifting of the surface plasmon resonance (SPR) band from 518 (AuNPs from the bulk [Au3Pz3]C10TEG complex) and 544 (calcination) to 558 nm.

Supramolecular Phosphorescent Trinuclear Copper(I) Pyrazolate Complexes for Vapochromic Chemosensors of Ethanol

“…4a). Such luminescent profile gave a large Stokes shift (∆λ) in 279, 304, 290, 322 and 338 nm, indicating the characteristics of phosphorescent compounds [21,[23][24][25][26][27][28][29][30][31][32][33][34]. Moreover, the luminescent decay measurements in excitation and emission maxima as shown in Fig.…”

Supramolecular assembly of group 11 phosphorescent metal complexes for chemosensors of alcohol derivatives

“…In-situ recrystallization was carried out using dry DCM and MeOH at room temperature to give solid powder of 2(Cu) after dried under reducing of vacuum pressure in 85% yields. The same procedure was repeated for synthesis other metal complexes using silver(I)hexafluorophosphate (AgPF6; 1.02 g, 4.06 mmol) and chloro(dimethyl sulfide) gold(I) ([Au(SMe2)]Cl; 1.19 g, 4.06 mmol) to give 2(Ag) and 2(Au) as white powder in 75% and 95% yields [19][20][21][22][23][24][25].…”

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

“…In our previous reports [31–32], we highlighted the morphology of mesoporous silica composites after both types of heat treatments at 450 and 250 °C by calcination for 3 hours and thermal hydrogen reduction for 2 hours. In this current work, we have only selected the best two samples from each heat treatment process (calcination at 250 °C and thermal hydrogen reduction at 210 °C) for the TEM measurements.…”

“…Recently, mesoporous silica nanomaterials were not only used as a support to control the size of the AuNPs [28], but also to enhance the thermal stability after heat treatment at high temperature [29]. In our previous works, high purity [Au 3 Pz 3 ] C10TEG [30] was used to fabricate [Au 3 Pz 3 ] C10TEG /silica hex for synthesizing AuNPs in the nanocomposites via calcination ([AuNPs] cal /silica hex ) [31] and thermal hydrogen reduction methods ([AuNPs] red /silica hex ) [32]. However, the resulting quality of the mesoporous silica nanomaterials was quite low based on their characteristic diffraction peaks and microscopy images.…”