Refinement of the Microwave‐Assisted Polyol Process for the Low‐Temperature Synthesis of Intermetallic Nanoparticles

Teichert, Johannes F.; Heise, Martin; Chang, Jinyuan; Ruck, Michael

doi:10.1002/ejic.201700966

Cited by 18 publications

(19 citation statements)

References 75 publications

(134 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2,3,4 Foremost among such "soft" chemistry routes is polyol co-reduction, where soluble metal precursors are heated in ethylene glycol or another mildly reducing solvent, usually to produce the desired intermetallic compound. 53,54,55,56,57,58,59,60 While the use of this method is widespread, it may result in phase segregated products due to the different reduction potentials of the metals. Another synthetic method, which is a modification of the polyol approach is coined 'ship-in-a-bottle'.…”

Section: Introductionmentioning

confidence: 99%

“…While many high-temperature solid-state methods to synthesize intermetallic compounds exist, low-temperature solution-phase methods provide some advantages: for example, in enabling the preparation of metastable phases or of intermetallics with smaller particle sizes with increased surface areas for catalytic applications. − Foremost among such “soft” chemistry routes is polyol coreduction, where soluble metal precursors are heated in ethylene glycol or another mildly reducing solvent, usually to produce the desired intermetallic compound. − While the use of this method is widespread, it may result in phase-segregated products due to the different reduction potentials of the metals. Another synthetic method, which is a modification of the polyol approach, is coined “ship in a bottle” .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Intermetallic Nanocatalysts from Heterobimetallic Group 10–14 Pyridine-2-thiolate Precursors

et al. 2020

View full text Add to dashboard Cite

Intermetallic compounds are atomically ordered inorganic materials containing two or more transition metals and main-group elements in unique crystal structures. Intermetallics based on group 10 and group 14 metals have shown enhanced activity, selectivity, and durability in comparison to simple metals and alloys in many catalytic reactions. While high-temperature solid-state methods to prepare intermetallic compounds exist, softer synthetic methods can provide key advantages, such as enabling the preparation of metastable phases or of smaller particles with increased surface areas for catalysis. Here, we study a generalized family of heterobimetallic precursors to binary intermetallics, each containing a group 10 metal and a group 14 tetrel bonded together and supported by pincer-like pyridine-2-thiolate ligands. Upon thermal decomposition, these heterobimetallic complexes form 10-14 binary intermetallic nanocrystals. Experiments and density functional theory (DFT) computations help in better understanding the reactivity of these precursors toward the synthesis of specific intermetallic binary phases. Using Pd2Sn as an example, we demonstrate that nanoparticles made in this way can act as uniquely selective catalysts for the reduction of nitroarenes to azoxyarenes, which highlights the utility of the intermetallics made by our method. Employing heterobimetallic pincer complexes as precursors toward binary nanocrystals and other metal-rich intermetallics provides opportunities to explore the fundamental chemistry and applications of these materials.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intermetallic Nanocatalysts from Heterobimetallic Group 10–14 Pyridine-2-thiolate Precursors

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Heise et al synthesized a plethora of intermetallic nanoparticles using various element combinations. [13][14][15] Even though the polyol process itself was studied and developed intensively over the last 30 years, there are still many details uncovered. Especially for intermetallic particles, little is known about the reaction and formation mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…[16][17][18] They systematically studied the formation of selected particles to elucidate the reaction mechanism and the influence of the solvents. [18,19] In the present study, the formation of bismuth-nickel particles, especially due to the interesting superconducting ferromagnetic behavior of micro-and nanostructured Bi 3 Ni [13,18] has been investigated in ethylene glycol (EG) as a solvent. Systematic experiments have been performed, changing reaction times, temperatures, pH values and metal salts.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Bi−Ni Phase Formation in a Microwave‐Assisted Polyol Process

et al. 2020

Self Cite

View full text Add to dashboard Cite

Typically, intermetallic phases are obtained in solid‐state reactions or crystallization from melts, which are highly energy and time consuming. The polyol process takes advantage of low temperatures and short reaction times using easily obtainable starting materials. The formation mechanism of these intermetallic particles has received little attention so far, even though a deeper understanding should allow for better synthesis planning. In this study, we therefore investigated the formation of BiNi particles in ethylene glycol in a microwave‐assisted polyol process mechanistically. The coordination behavior in solution was analyzed using HPLC‐MS and UV‐Vis. Tracking the reaction with PXRD measurements, FT‐IR spectroscopy and HR‐TEM revealed a successive reduction of Bi3+ and Ni2+, leading to novel spherical core‐shell structure in a first reaction step. Bismuth particles are encased in a matrix of nickel nanoparticles of 2 nm to 6 nm in diameter and oxidation products of ethylene glycol. Step‐wise diffusion of nickel into the bismuth particle intermediately results in the bismuth‐rich compound Bi3Ni, which consecutively transforms into the BiNi phase as the reaction progresses. The impacts of the anion type, temperature and pH value were also investigated.

show abstract

“…Recently, progress was made in the synthesis of intermetallic compounds by mild “soft” chemistry methods (Scheme ). , One approach involves dissolving separate metal salts in tetraethylene glycol, which acts as a mild reducing agent under relatively modest temperatures. − This “modified polyol synthesis” method can be limited due to the different reduction potentials of the separate metal ions, leading in some cases to phase-segregated products rather than to the desired intermetallic compound. Very recently, a new templated approach was developed to overcome this problem .…”

Section: Introductionmentioning

confidence: 99%

Heterobimetallic Single-Source Precursors: A Springboard to the Synthesis of Binary Intermetallics

et al. 2019

View full text Add to dashboard Cite

Intermetallics are atomically ordered crystalline compounds containing two or more main group and transition metals. In addition to their rich crystal chemistry, intermetallics display unique properties of interest for a variety of applications, including superconductivity, hydrogen storage, and catalysis. Because of the presence of metals with a wide range of reduction potentials, the controlled synthesis of intermetallics can be difficult. Recently, soft chemical syntheses such as the modified polyol and ship-in-a-bottle methods have helped advance the preparation of these materials. However, phase-segregated products and complex multistep syntheses remain common. Here, we demonstrate the use of heterobimetallic single-source precursors for the synthesis of 10–15 and 11–15 binary intermetallics. The coordination environment of the precursor, as well as the exact temperature used play a critical role in determining the crystalline intermetallic phase that is produced, highlighting the potential versatility of this approach in the synthesis of a variety of compounds. Furthermore, we show that a recently developed novel plasma-processing technique is successful in removing the surface graphitic carbon observed in some of the prepared compounds. This new single-source precursor approach is a powerful addition to the synthesis of atomically ordered intermetallic compounds and will help facilitate their further study and development for future applications.

show abstract

Refinement of the Microwave‐Assisted Polyol Process for the Low‐Temperature Synthesis of Intermetallic Nanoparticles

Cited by 18 publications

References 75 publications

Intermetallic Nanocatalysts from Heterobimetallic Group 10–14 Pyridine-2-thiolate Precursors

Intermetallic Nanocatalysts from Heterobimetallic Group 10–14 Pyridine-2-thiolate Precursors

Mechanism of Bi−Ni Phase Formation in a Microwave‐Assisted Polyol Process

Heterobimetallic Single-Source Precursors: A Springboard to the Synthesis of Binary Intermetallics

Contact Info

Product

Resources

About