Facile Synthesis of Rhodium Icosahedra with Controlled Sizes up to 12 nm

Abstract

We reportafacile synthesiso fR hi cosahedra with average sizes up to 12.0 AE 0.8 nm through the use of ar elatively slow reduction process. By using Rh(acac) 3 as ap recursor to Rh and poly(vinylp yrrolidone) (PVP) as ar educing agent, the reduction kinetics can be manipulateds uch to promote the formation of twin defects in the Rh nanocrystals. When Rh(acac) 3 is replaced by other precursors containing mono-dentate ligands, single-crystal Rh nanocrystals are obtained due to the acceleration of reduction rate. By in-creasingt he molecular weight of PVP from 10 000 to 1300 000, the resulting Rh nanocrystals are transformed from single-crystal octahedra to multiply twinned icosahedra and stacking-fault-lined plates. These results suggestt hat the successful preparation of Rh icosahedra could be facilitated by varying the binding strength of al igand to Rh in the precursor and/ort he molecular weight of PVP to optimize the reduction kinetics.[a] Prof.

Nanocatalysis by noble metal nanoparticles: controlled synthesis for the optimization and understanding of activities

“…Thus, in the context of the catalytic reaction itself, only surface atoms are considered active and, therefore, in addition to their reactivity, their availability relative to the atoms in the interior of the nanoparticle is crucial. 24,34,58,[85][86][87] Hence, it is not a surprise that the size-controlled synthesis of metal nanomaterials is an important strategy to improve the catalytic activity per mass unit of metal. In addition to increased surface areas, size can also enable the exposure of more reactive sites, such as surface defects, low-coordination, and unsaturated atoms.…”

Designing Efficient Catalysts through Bimetallic Architecture: Rh@Pt Nanocubes as a Case Study

“…Shape‐controlled metal nanoparticles (NPs) are finding use as heterogeneous catalysts, as symmetry matched surface–adsorbate interactions can be selected through the expression of specific facets . In fact, there are numerous reports of the catalytic activity, selectivity, and stability of nanocatalysts being enhanced by manipulation of NP size or shape . This control can be augmented through NP composition, with bimetallic NPs often yielding increased performance over their monometallic counterparts .…”

“…[1][2][3] In fact, there are numerous reports of the catalytic activity,s electivity,a nd stabilityo fn anocatalysts being enhanced by manipulationo fN Ps ize [4][5][6] or shape. [7][8][9][10][11][12] This control can be augmented through NP composition, with bi-metallicN Ps often yieldingi ncreased performance over their monometallic counterparts. [13][14][15][16][17][18][19][20][21][22] Such enhancements arise from the ability to controlt he electronic structure of the surface throughs train ande lectron transfer between metals.…”

Rhodium Decahedral Nanocrystals: Facile Synthesis, Mechanistic Insights, and Experimental Controls

“…In 2010, our group reported the synthesis of starfish‐like Rh nanocrystals with five twinned arms by preventing oxidative etching in a polyol synthesis . More recently, we successfully synthesized thirty‐fold twinned Rh icosahedra with well‐defined {111} facets by optimizing the reaction conditions . In a typical synthesis, benzyl alcohol containing Rh(acac) 3 , PVP (MW≈40 kDa), and 4‐benzoylbenzoic acid was heated to 195 °C under vigorous stirring for 3 h. The success of this reaction was attributed to the deceleration of the initial reduction rate of a Rh precursor to facilitate the formation of multiply‐twinned seeds.…”