Metal Nanoclusters Synthesized in Alkaline Ethylene Glycol: Mechanism and Application

Abstract

The “unprotected” metal and alloy nanoclusters (UMCs) prepared by the alkaline ethylene glycol method, which are stabilized with simple ions and solvent molecules, have the advantages of a small particle size, a narrow size distribution, good stability, highly efficient preparation, easy separation, surface modification and transfer between different phases. They can be composited with diverse materials to prepare catalytic systems with controllable structures, providing an effective means of studying the different factors’ effects on the catalytic properties separately. UMCs have been widely used in the development of high-performance catalysts for a variety of functional systems. This paper will review the research progress on the formation mechanism of the unprotected metal nanoclusters, exploring the structure–function relationship of metal nanocluster catalysts and the preparation of excellent metal catalysts using the unprotected metal nanoclusters as building blocks or starting materials. A principle of the influence of carriers, ligands and modifiers in metal nanocluster catalysts on the catalytic properties is proposed.

Tailoring Hydrogen Evolution Performance: Size and Phase Engineering of Ruthenium Nanoparticles

“…From the R ( r ) fits shown in Figure , the model reveals a triphase Ru P 6/ mmc , β-RuCl 3 P 6 3 / mcm, and RuO 2 P 4 2 / mnm system. The thermal phase transition from the precursor RuCl 3 ·3H 2 O to a mixture of crystalline Ru, α-RuCl 3, β-RuCl 3 , and RuO 2 has previously been observed. − The refinement of the total scattering studies uniquely allows for the measurement of fractional concentration and identification of intermediary phases β-RuCl3 ( P 6 3 / mmc ) and RuO 2 ( P 4 2 / mnm ) in the Ru nanoparticle system. From the total scattering studies, it is observed that as the annealing temperature is increased, there is an increase in the desired phase fraction of Ru ( P 6 3 / mmc ); conversely, there is a reduction in the intermediary phase fractions of β-RuCl 3 ( P 6 3 / mcm ) and RuO 2 ( P 4 2 / mnm ).…”

Surfactant-Free Colloidal Syntheses of Precious Metal Nanoparticles for Improved Catalysts

“…One can use the same colloidal stock dispersion to compare "bare" particles to differently functionalized ones, e.g., to assess the effect of ligand functionalization. Since LSPC, 1 SPP, 142 or DMF based syntheses 31 have been reviewed recently, and an account for ligand-free syntheses for electrocatalysis has just been proposed, 93 here catalytic studies using surfactant-free NPs obtained by the polyol 192 and monoalcohol syntheses are detailed. Rather than summarizing different reactions where surfactant-free NPs were successfully used and for which an account is given in Table S1 and Table 2, we present an overview of the common strategy to investigate and optimize the influence of a given parameter affecting the properties of a catalyst.…”

“…In the context of the present review, it must be stressed than since 2000 and the pioneer work of Wang et al , it has actually been well established that there is no need for surfactants in the synthesis of precious metal NPs by the polyol method (see Figure ). Conveniently, the approach is not very sensitive to the concentration of metal: a size of 1–2 nm is obtained for Pt NPs regardless of the concentration of precursor (0.4–51 mM).…”