Mechanistic Insights into a Non‐Classical Diffusion Pathway for the Formation of Hollow Intermetallics: A Route to Multicomponent Hollow Structures

Anumol, E. A.; Nethravathi, C.; Ravishankar, N.

doi:10.1002/ppsc.201300022

Cited by 9 publications

(7 citation statements)

References 59 publications

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“…Subsequently, the Bi 3+ ions were gradually reduced and Pd/Bi atoms interdiffused to form the ordered structure at higher temperatures. The diffusion of Pd to the surface could be influenced by the segregation energy and curvature, while the diffusion barrier of Bi was decreased during the annealing reductive process due to the generation of vacancies, which are formed due to the removal of O and Cl. − Further increasing the concentration of Bi helps in the formation of β-PdBi at a lower temperature, although with increased byproducts (Figure S1b). Thus, the interdiffusion rate of Bi and Pd atoms is mainly responsible for the formation of the ordered β-PdBi structure.…”

Section: Resultsmentioning

confidence: 99%

Tailoring the Antipoisoning Performance of Pd for Formic Acid Electrooxidation via an Ordered PdBi Intermetallic

et al. 2020

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Pd-based materials are promising electrocatalysts for the formic acid oxidation reaction (FAOR) but suffer from poor durability due to the poisoning of adsorbed carbon monoxide species (COads). In this work, PdBi ordered intermetallic (O-PdBi) nanoparticles were prepared in an effort to mitigate the formation of adsorbed species like COads through isolating the Pd atoms. The enhanced antipoisoning capability of O-PdBi, relative to Pd, gave rise to superior activity and stability during FAOR. Differential electrochemical mass spectrometry (DEMS) and CO stripping results indicated that COads could be removed more easily on O-PdBi compared with that on Pd. In situ attenuated total reflection-infrared spectroscopy showed that the formation of COads on O-PdBi was effectively suppressed, while both the hollow and bridged COads were detected on Pd with continuous Pd sites. In addition to the higher content of Bi atoms on the Pd-Bi surface, the ordered atomic distribution has played an important role in this effect. This work demonstrates the superiority of ordered intermetallic Pd-based nanocatalysts and provides guidance for promoting stability in FAOR by precluding the formation of COads.

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Section: Resultsmentioning

confidence: 99%

Tailoring the Antipoisoning Performance of Pd for Formic Acid Electrooxidation via an Ordered PdBi Intermetallic

et al. 2020

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“…Anumol et al conducted in situ TEM studies of the formation of hollow intermetallic PtBi NPs. 143 A solution containing H 2 PtCl 6 and Bi(acetate) 3 was microwave heated at 100 °C. Initially, small Pt NPs grew and formed larger aggregates (Fig.…”

Section: Void Formation Through Solid-state Diffusion Couplesmentioning

confidence: 99%

Nanoparticle conversion chemistry: Kirkendall effect, galvanic exchange, and anion exchange

2014

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Conversion chemistry is a rapidly maturing field, where chemical conversion of template nanoparticles (NPs) into new compositions is often accompanied by morphological changes, such as void formation. The principles and examples of three major classes of conversion chemical reactions are reviewed: the Kirkendall effect for metal NPs, galvanic exchange, and anion exchange, each of which can result in void formation in NPs. These reactions can be used to obtain complex structures that may not be attainable by other methods. During each kind of conversion chemical reaction, NPs undergo distinct chemical and morphological changes, and insights into the mechanisms of these reactions will allow for improved fine control and prediction of the structures of intermediates and products. Conversion of metal NPs into oxides, phosphides, sulphides, and selenides often occurs through the Kirkendall effect, where outward diffusion of metal atoms from the core is faster than inward diffusion of reactive species, resulting in void formation. In galvanic exchange reactions, metal NPs react with noble metal salts, where a redox reaction favours reduction and deposition of the noble metal (alloying) and oxidation and dissolution of the template metal (dealloying). In anion exchange reactions, addition of certain kinds of anions to solutions containing metal compound NPs drives anion exchange, which often results in significant morphological changes due to the large size of anions compared to cations. Conversion chemistry thus allows for the formation of NPs with complex compositions and structures, for which numerous applications are anticipated arising from their novel catalytic, electronic, optical, magnetic, and electrochemical properties.

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“…With a higher magnification (Figure d and inset in d), the hollow structured Pt–Ni NPs with an average size of 10 nm can be clearly seen. The hollow Pt–Ni NPs synthesized by this simple method surprised us because such structures of Pt-M alloys are generally synthesized using the galvanic replacement, − template-assisted method, , and Kirbendall effect. − Recently, there has been a popular method to synthesize hollow PtNi/C , or PtCo/C nanocrystallites involving the galvanic replacement and the nanoscale Kirkendall effect. The hollow structure can be first formed during the galvanic replacement between Pt z+ ions and Ni-rich/C or Co-rich/C templates.…”

Section: Resultsmentioning

confidence: 99%

Newly Designed Graphene Cellular Monolith Functionalized with Hollow Pt-M (M = Ni, Co) Nanoparticles as the Electrocatalyst for Oxygen Reduction Reaction

Zhou

Yang

Zhu

et al. 2016

ACS Appl. Mater. Interfaces

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Newly designed graphene cellular monoliths (GCMs) functionalized with hollow Pt-M nanoparticles (NPs) (Pt-M/GCM, M = Ni, Co) have been successfully achieved by a facile and powerful method on the basis of sonochemical-assisted reduction and gelatinization processes. First, hollow Pt-M (M = Ni, Co) NPs were synthesized and distributed on graphene oxide sheets (Pt-M/GO) by sodium borohydride reduction of metal precursors in the ultrasonic environment. Second, the hollow structure was further formed by ascorbic acid (AA) reduction of Pt precursors in gelatinization process. Meanwhile, GO sheets with hollow Pt-M NPs were reduced to graphene, and were assembled into Pt-M/GCM hydrogels by gelatinization process. The Pt-M/GCM (M = Ni, Co) electrocatalysts have a factor of 9.4-18.9 enhancement in electrocatalytic activity and higher durability toward oxygen reduction reaction (ORR), compared with those of commercial Pt/C catalyst. In detail, the mass activities for Pt-Ni/GCM and Pt-Co/GCM are 1.26 A mg and 1.79 A mg, respectively; meanwhile, the corresponding specific activities are 1.03 and 2.08 mA cm. The successful synthesis of such attractive materials paves the way to explore a series of porous materials in widespread applications.

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Mechanistic Insights into a Non‐Classical Diffusion Pathway for the Formation of Hollow Intermetallics: A Route to Multicomponent Hollow Structures

Cited by 9 publications

References 59 publications

Tailoring the Antipoisoning Performance of Pd for Formic Acid Electrooxidation via an Ordered PdBi Intermetallic

Tailoring the Antipoisoning Performance of Pd for Formic Acid Electrooxidation via an Ordered PdBi Intermetallic

Nanoparticle conversion chemistry: Kirkendall effect, galvanic exchange, and anion exchange

Newly Designed Graphene Cellular Monolith Functionalized with Hollow Pt-M (M = Ni, Co) Nanoparticles as the Electrocatalyst for Oxygen Reduction Reaction

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