&amp;lt;i&amp;gt;In&amp;lt;/i&amp;gt;-&amp;lt;i&amp;gt;Situ&amp;lt;/i&amp;gt; XAFS Characterization of PtPd Nanoparticles Synthesized by Galvanic Replacement

Tymen, Simon; Scheinost, Andreas C.; Friebe, Christian; Schubert, Ulrich S.

doi:10.4236/anp.2017.62007

Cited by 3 publications

(2 citation statements)

References 32 publications

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“…In contrast to the monometallic system, it is difficult to provide a straightforward explanation for these peaks that are typically observed in PtPd bimetallic systems. [ 47–50 ] This is because PtPt and PtPd bond distances are very similar to each other, as also reported in our fitting results. Nonetheless, it is possible to discuss the atomic coordination from the EXAFS spectrum.…”

Section: Resultssupporting

confidence: 85%

Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

Shin

Park

et al. 2021

Adv Funct Materials

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Single‐atom catalysts (SACs) supported on inorganic materials have attracted much attention in numerous research fields for their high catalytic performance. However, such SACs have been limited by the low metal loading, especially on different types of inorganic supports. Herein, a general approach is presented for preparing SACs on metallic, metal oxide, and perovskite nanosheet (NS) supports to reach a high metal loading of up to 3.94 wt%, by utilizing N‐doped graphene as a sacrificial template that spatially confines the single atoms (SAs). Specifically, the target support material precursors are adsorbed onto the SAs‐stabilized sacrificial template, followed by subsequent heat treatment to transfer the SAs to the support material and to remove the graphene layer. Pt SAs on oxide support exhibits little to no aggregation throughout >10 000 min of annealing at 275 °C, demonstrating high thermal stability, as also supported by ex situ post‐anneal electron microscopy and X‐ray absorption fine structure studies. As a proof‐of‐concept, Pt SACs on SnO2 NSs exhibit high catalytic activity toward chemiresistive sensing of acetone gas (response = 95.4 at 10 ppm, 7.6‐fold enhancement compared with pristine SnO2 NSs) and unprecedented stability under highly humid conditions (27.4% response deterioration at 95% relative humidity).

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Section: Resultssupporting

confidence: 85%

Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

Shin

Park

et al. 2021

Adv Funct Materials

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“…The kinetic current density j k is calculated with the values of the current densities j at 0.85 V and j L at 0.50 V for the anodic scan. The received kinetic current density at 0.85 V was normalized to the mass of catalyst (m PtPd ) to compare the catalytic performances of the particles for the ORR: [8] For the different samples, the ORR mass activities were determined (Table IV) whereas the Pd nanocubes show the lowest mass activity (4.8 A. g −1 ) due to the absence of Pt. It is known from literature that Pd possesses a significantly lower catalytic activity for the oxygen reduction reaction in acid media than Pt or bimetallic NPs based on Pd alloys 30 or core-shell structures.…”

Section: Characterization Of the Ptpd Nanoparticles By Tem And Eds-mentioning

confidence: 99%

From Cubic Palladium to Concave Core-Shell Platinum Palladium Nanoparticles: Evolution of the Structure and Their Electrochemical Properties

Tymen¹,

Scheinost²,

Lozano-Rodriguez³

et al. 2018

J. Electrochem. Soc.

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of the particles (with and without oxide). With the iterative transfer factor analysis (IFTA), we followed the relative concentration of the oxide at different potentials. 8 MethodSynthesis of PtPd nanoparticles.-Depending on the particle's type, size, shape, and composition, different methods were used to synthesize PtPd nanoparticles (NPs) in aqueous or organic solution. [9][10][11] Inspired by the method of Zhang et al., using galvanic replacement for the synthesis of bimetallic core-shell nanoparticles 12 or PtPd alloy nanocages, 13 the hexachloroplatinic acid (H 2 PtCl 6 ) was replaced by potassium tetrachloroplatinate (K 2 PtCl 4 ), Sigma Aldrich, 98%), which possesses platinum(II) instead of platinum(IV). The particles were prepared in two steps by galvanic replacement: Firstly the synthesis of cubic Pd nanoparticles, followed by the preparation of the core (Pd)-shell (Pt) nanoparticles. The synthesis of the Pd NPs was performed in aqueous solution: 0.6 g of ascorbic acid (AA, Sigma Aldrich, 98%), 3 g of potassium bromide (KBr, Sigma Aldrich, 99%), 1.85 g of potassium chloride (KCl, Sigma Aldrich, 99%), and 1.05 g of poly(vinylpyrrolidone) (PVP, Alfa Aesar, 98%) were added to 80 mL of distilled water. The solution was sonicated for 2 min and heated to 80 • C. After 10 min, 30 mL of sodium tetrachloropalladate (Na 2 PtCl 4 , 6.5 × 10 −2 mol L −1 , Sigma Aldrich, 98%) were added with a syringe (1 mL min −1 ). Afterward, the solution was maintained at 80 • C under magnetic stirring for 3.5 h. The PtPd NPs were prepared in a second step: 10 mL of the solution containing Pd nanoparticles were mixed with 70 mL of an aqueous solution composed of 3 g of KBr and 0.333 g of PVP. The solution was heated to 90 • C and 30 mL of K 2 PtCl 4 (3 × 10 −3 mol L −1 , Sigma Aldrich, 98%) were added (1 mL min −1 ) under magnetic stirring. Different times of synthesis were used to study the evolution of the particles: 0.6 h, 2 h, 4 h, 6 h, 8 h, and 17 h. After the synthesis, the particles, collected by centrifugation, were washed and rinsed several times with water and ethanol. Afterwards, the solution containing clean particles was dried in the oven at 70 • C.Coating the particles on carbon powder.-For a sample, composed of 40% particles and 60% of carbon, 40 mg of particles were added to 25 mL of ethylene glycol (VWR), and the mixture was sonicated for 15 min. A mixture of 60 mg of Vulcan XC-72R carbon powder in 25 mL of ethylene glycol at pH 2 (adjusted with

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Insights and comparison of structure–property relationships in propane and propene catalytic combustion on Pd- and Pt-based catalysts

Yang

Streibel

Choksi

et al. 2021

Journal of Catalysis

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<i>In</i>-<i>Situ</i> XAFS Characterization of PtPd Nanoparticles Synthesized by Galvanic Replacement

Cited by 3 publications

References 32 publications

Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

From Cubic Palladium to Concave Core-Shell Platinum Palladium Nanoparticles: Evolution of the Structure and Their Electrochemical Properties

Insights and comparison of structure–property relationships in propane and propene catalytic combustion on Pd- and Pt-based catalysts

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