Liquid–liquid interface-mediated room-temperature synthesis of amorphous NiCo pompoms from ultrathin nanosheets with high catalytic activity for hydrazine oxidation

Wang, Hui; Ma, Yanjiao; Wang, Rongfang; Key, Julian; Linkov, Vladimir; Ji, Shan

doi:10.1039/c4cc09928a

Cited by 65 publications

(37 citation statements)

References 35 publications

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“…S8a . In acidic electrolyte, the Tafel slopes are 53 and 289 mV dec −1 in the low and high potential regions, respectively, indicating that the mechanism possibly follows the processes of (i) b-Pd@Rh-NCs + NH 2 NH 3 + ↔ b-Pd@Rh‒NHNH 2 + 2 H + + e − and then (ii) b-Pd@Rh‒NHNH 2 → b-Pd@Rh-NCs + N 2 + 3 H + + 3e − , where the rate-determining step is believed to be the first dehydrogenation step (i) based on the comparison of the current and previous literature data 12 , 13 . However, in alkaline solution, much lower Tafel slopes of 15 and 206 mV dec −1 are separately obtained in the low and high potential regions (Fig.…”

Section: Resultsmentioning

confidence: 99%

Branched Pd@Rh core@shell nanocrystals with exposed Rh {100} facets: an effective electrocatalyst for hydrazine electro-oxidation

Wang

Jing

Tan

2017

Sci Rep

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Shape control of noble metal (NM) nanocrystals (NCs) is of great importance for improving their electrocatalytic performance. In this report, branched Pd@Rh core@shell NCs that have right square prism-like arms with preferential exposure of Rh {100} facets (denoted as b-Pd@Rh-NCs thereafter) are synthesized and utilized as an electrocatalyst for the hydrazine electrooxidation (HEO) in acidic and alkaline electrolytes. The b-Pd@Rh-NCs are obtained by the heteroepitaxial growth of Rh on the pre-formed branched Pd NCs (denoted as b-Pd-NCs thereafter) core in the presence of poly(vinyl pyrrolidone) (PVP) and bromide ions. A comparative analysis of the voltammetric data for the HEO shows a higher activity on the b-Pd@Rh-NCs exposed with Rh {100} faces than on Rh black, the b-Pd-NCs, and Pd black in acid and alkaline solutions, indicating a structure sensitivity of the reaction. Analysis of the products from the b-Pd@Rh-NCs catalysed HEO reveals a very high hydrazine fuel efficiency, as determined by on-line differential electrochemical mass spectrometry (DEMS).

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Section: Resultsmentioning

confidence: 99%

Branched Pd@Rh core@shell nanocrystals with exposed Rh {100} facets: an effective electrocatalyst for hydrazine electro-oxidation

Wang

Jing

Tan

2017

Sci Rep

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“…And because of this, if Pt shells are attached to Au, the surface redox properties of the Pt shells are changed, improving stability [431]. For example, Zhang et al [428] reported an Au/Pt/C electrode which displayed no apparent loss of ECSA and only 5 mV degradation of ORR halfwave potential (E 1/2 ) after cycling between 0.6 and 1.1 V (vs. RHE) for 30,000 cycles in HClO 4 (Fig. 25), whereas a Pt/C electrode displayed a 45% ECSA loss and a 39 mV negative shift of ORR E 1/2 .…”

Section: Au As Corementioning

confidence: 99%

“…For example, based on kinetic limitation effects, smooth and near perfect Pt monolayers can be grown in the absence of UPD-type energetic stabilization by using a flow cell setup [296,309]. In another example, Tao et al [312] modified a Cu-UPD process by carefully preparing a UPD solution containing Cu, CuSO 4 and AA to allow the process to be free of potential control, resulting in 1~2 nm Pt nanoclusters being deposited onto Pd nanorods. Adzic et al [289] also performed the Cu-UPD twice to deposit double shells consisting of an outmost monolayer shell of Pt and a monolayer subshell of PdAu onto a Pd core.…”

Section: Principles and Development Of Electrodepositionmentioning

confidence: 99%

“…And among the various fuel cell technologies, low-temperature fuel cells (LTFCs) represented by proton exchange membrane fuel cells (PEMFCs) are attracting special attention because of their high energy density and relatively low working temperatures, making them suitable for mobile and stationary applications [2]. The automotive industry has also been researching fuel cell-powered vehicles for commercialization to replace conventional internal combustion vehicles [4][5][6]. However, the commercialization of fuel cell vehicles is severely impeded by several issues with the major issue being the prohibitive cost, with the current cost of FCVs being approximately $350 kW −1 net ( Fig.…”

Section: Low-temperature Fuel Cells and Pt-based Catalystsmentioning

confidence: 99%

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Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Wang

Luo

et al. 2018

Electrochem. Energ. Rev.

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Pt-based catalysts are the most efficient catalysts for low-temperature fuel cells. However, commercialization is impeded by prohibitively high costs and scarcity. One of the most effective strategies to reduce Pt loading is to deposit a monolayer or a few layers of Pt over other metal cores to form core-shell-structured electrocatalysts. In core-shell-structured electrocatalysts, the compositions of the core can be divided into five classes: single-precious metallic cores represented by Pd, Ru, and Au; singlenon-precious metallic cores represented by Cu, Ni, Co, and Fe; alloy cores containing 3d, 4d or 5d metals; and carbide and nitride cores. Of these, researchers have found that carbide and nitride cores can yield tremendous advantages over alloy cores in terms of cost and promotional activities of Pt shells. In addition, desirable shells with reasonable thicknesses and compositions have been recognized to play a dominant role in electrocatalytic performances. And recently, researchers have also found that the catalytic activity of core-shell-structured catalysts is dependent on the binding energy of the adsorbents, which is determined by the d-band center of Pt. The shifting of this d-band center in turn is mainly affected by strain and electronic effects, which can be adjusted by adjusting core compositions and shell thicknesses of catalysts. In the development of these core-shell structures, optimal synthesis methods are of primary concern because they directly determine the practical application potential of the resulting electrocatalysts. And in this article, the principles behind core-shell-structured low-Pt electrocatalysts and the developmental progresses of various synthesis methods along with the traits of each type of core and its effects on Pt shell catalytic activities are discussed. In addition, perspectives on this type of catalyst are discussed and future research directions are proposed.

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“…In alkaline environment, the electrode reaction kinetics has been observed to be higher than those in acid medium, and non‐noble metal catalysts in such medium exhibit better stability . Up to date, a number of non‐noble metals and their alloys for hydrazine oxidation have been investigated, including Co, Cu, Ni and binary and/or ternary Ni‐based metal catalysts (Ni−M, M=Co, Cu, Fe, Zn, B and S) . Among these catalysts reported, the performance of Ni−Zn alloy due to alloying effects stands out as the top level of anode catalysts in DHFCs .…”

Section: Introductionmentioning

confidence: 99%

Ni−Zn Alloy Nanosheets Arrayed on Nickel Foamas a Promising Catalyst for Electrooxidation of Hydrazine

Dai

Wen

et al. 2017

ChemElectroChem

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The development of cost‐effective electrocatalysts is a key issue to promote the practical application of hydrazine as a viable energy carrier. Herein, a nickel‐foam‐supported Ni−Zn alloy catalyst is synthesized by electrodeposition and anodic dissolution methods. The developed catalyst with an opennanowall network structure and robust adhesion exhibits high activity and good durability for electrooxidation of hydrazine in an alkaline medium. For example, a current density of 300 mA cm−2at 0.40 Vand an onset potential of −0.15 V vs. the reversible hydrogen electrode are achieved in a 0.10 M hydrazine and 1.0 M NaOH solution at 30 °C. Phase and structure analysis by XRD, SEM, and XPS is conducted to gain insight into the excellent catalytic performance of theNi−Zn alloy catalyst. Such an understanding is of particular importance in the design of efficient non‐precious catalysts.

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Liquid–liquid interface-mediated room-temperature synthesis of amorphous NiCo pompoms from ultrathin nanosheets with high catalytic activity for hydrazine oxidation

Cited by 65 publications

References 35 publications

Branched Pd@Rh core@shell nanocrystals with exposed Rh {100} facets: an effective electrocatalyst for hydrazine electro-oxidation

Branched Pd@Rh core@shell nanocrystals with exposed Rh {100} facets: an effective electrocatalyst for hydrazine electro-oxidation

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Ni−Zn Alloy Nanosheets Arrayed on Nickel Foamas a Promising Catalyst for Electrooxidation of Hydrazine

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