Synthesis of sinter-resistant Au@silica catalysts derived from Au₂₅ clusters

Abstract

Au25L18 clusters have been encapsulated in silica spheres to create sinter-resistant Au@SiO2 materials which are active and recyclable epoxidation catalysts.

Activation of atomically precise silver clusters on carbon supports for styrene oxidation reactions

“…The catalytic performances of the as-prepared and activated Ag 25 13 Products were then analyzed using a gas chromatograph (7890A, Agilent Technologies) equipped with a HP-5 column and a ame ionization detector.…”

“…[26][27][28][29][30] Both naked and protected Au 25 clusters have been reported to be active catalysts for styrene oxidation, 10,31 and several groups including our group have shown size-dependent activity of Au clusters, with high selectivity towards styrene oxide. 10,13 Ag nanoparticles have also shown to be effective catalysts for styrene epoxidation, though the use of a secondary promoter is a common practice to achieve high selectivity of the epoxide product. 32,33 Then, selective styrene epoxidation can serve as a good model oxidation reaction to assess the activity of atomically-precise Ag cluster catalysts.…”

Sintering‐Resistant Metal Catalysts Supported on Concave‐Convex Surface of TiO2 Nanoparticle Assemblies

“…[1][2][3][4][5][6][7][8][9][10][11] To obtain good dispersibility of NPs, the surface of metal NPs are directly modified with organic materials or the NPs are mixed with dispersion media such as fatty acids and amines with long alkyl chains. [27][28][29][30][31][32][33][34][35][36][37] These strategies mainly focus on the isolation of the individual nanocatalyst, resulting in low possibility of catalyst aggregation/growth. [15][16][17][18][19][20][21] Metal oxides are the most commonly used supports, because they not only have high heat tolerance and mechanical strength required for very high temperatureÀhigh pressure reactions, but also provide a wide surface area for dilution effect to occur that releases reaction heat.…”

“…[27][28][29][30][31][32][33][34][35][36][37] These strategies mainly focus on the isolation of the individual nanocatalyst, resulting in low possibility of catalyst aggregation/growth. [27][28][29][30][31][32][33][34][35][36][37] These strategies mainly focus on the isolation of the individual nanocatalyst, resulting in low possibility of catalyst aggregation/growth.…”

“…Thus, it is better to focus on the prevention of sintering and leaching rather than to regenerate the NPs.To prevent the sintering and leaching of metal NPs, several methods such as alloying, ligand-assisted pinning, fixing on defects, and encapsulating as core-shell/sheath structures by oxides or polymer have been reported. [27][28][29][30][31][32][33][34][35][36][37] These strategies mainly focus on the isolation of the individual nanocatalyst, resulting in low possibility of catalyst aggregation/growth. However, some of them reduce the accessibility of the reactant to the active sites of the catalyst NPs, which lead to a lowering in their reaction rate.…”