Superior Catalysts for Oxygen Reduction Reaction Based on Porous Nanostars of a Pt, Pd, or Pt–Pd Alloy Shell Supported on a Gold Core

Venarusso, Luna B.; Bettini, Jefferson

doi:10.1002/celc.201600046

Cited by 28 publications

(20 citation statements)

References 38 publications

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“…Figures and S2). These structures with highly rough surface can be ascribed to the presence of Pluronic F‐127 during the synthesis procedure . Furthermore, one notices the presence of clear crystalline pattern of Pt or Pt alloy, e. g., the lattice fringes with an average distance of 0.22 nm observed mainly at the rough external part of the particles (black lines, Figure C), which is expected for planes (1 1 1) of face‐centered cubic crystalline Pt systems .…”

Section: Resultsmentioning

confidence: 99%

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Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

2020

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Over the last few years, there has been an intensive search for stable and highly active electrocatalysts, which are intended to be applied in oxygen reduction reaction (ORR) preferably without the use of noble metals or with the application of a very small quantity of these metals in the process. Electrocatalysts that satisfy these conditions can be composed of Ti and other metals, supported or not by carbonaceous materials. The present work reports the application of synthesized threedimensional Ti/PtÀ Pd nanoparticles with highly rough surfaces supported on graphene nanoribbons (Ti/PtÀ Pd/GNR nanocomposite) by a single one-pot reaction, and applied in ORR. Unlike the effect of strong metal-support interaction (SMSI), which favors electrons transfer from the metal support to the catalyst, the mechanism employed in this study favored the transfer of electrons from the catalyst to the metal support; in other words, the mechanism led to the oxidation of Pt and Pd. Pt, which exhibited PtÀ Pd type alloy features, was found to be more externally distributed at the rough surface of the metallic structures. Additionally, Ti, which presented oxide features, was found to be even more externally distributed at the surface of PtÀ Pd on non-electrochemically and electrochemically stabilized Ti/PtÀ Pd/GNR nanocomposite electrodes. Since all these metals have great amounts of different oxides (i. e. are highly oxidized), the oxides are found to be energetically responsible for the improvement in ORR electrocatalytic activity and stability of Ti/PtÀ Pd/GNR/GC electrodes in comparison with the ORR responses for PtC TKK/GC and PtÀ Pd/GNR/GC modified electrodes. To Ti-containing catalysts, the high activity is attributable to enhancing the intrinsic activity and the high selectivity to 4-electron ORR is due to the fact that presence of Ti contributes to oxygen-binding energy of these nanocomposites shifts toward more positive values (weakening oxygen bonding).[a] G.

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Section: Resultsmentioning

confidence: 99%

“…Visible metallic structures with highly rough surface can be observed on GNR (Figures , S1, and S2) with PSD of 12.8±3.4 nm on average (c.f. Figures and S2).…”

Section: Resultsmentioning

confidence: 99%

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

2020

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“…where J is the measured current density, J K and J L are the kinetic and diffusion-limiting current densities, B = 0.62nFCo 2 D 2/3 u À1/6 , w is the angular velocity of the disk (w = 2pN, N is the linear rotation speed), n is transferred electron number, F is the Faraday constant (96485 C · mol À1 ), Co 2 is the concentration of dissolved oxygen in electrolyte (0.84 10 À6 mol · cm À3 in 0.1 mol · L À1 KOH, 1.26 10 À6 mol · cm À3 in 0.1 mol · L À1 HClO 4 ), [52,53] D is the diffusion coefficient of dissolved oxygen (1.65 10 À5 cm 2 · s À1 in 0.1 mol · L À1 KOH, 1.93 10 À5 cm 2 · s À1 in 0.1 mol · L À1 HClO 4 ), [52,53] and v is the kinematic viscosity of the electrolyte (0.01 cm 2 · s À1 ). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 …”

Section: Electrochemical Measurementsmentioning

confidence: 99%

Doping Copper Ions into an Fe/N/C Composite Promotes Catalyst Performance for the Oxygen Reduction Reaction

Wei

Wang

et al. 2017

ChemElectroChem

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Developing new non-precious-metal catalysts for the cathodic oxygen reduction reaction (ORR) in low-temperature fuel cells is highly desirable for replacing Pt-based noble-metal electrocatalysts. Herein, we report a two-step method to prepare Fe, Cu, and N-doped reduced graphene oxide/carbon nanotube (rGO/CNT) composites through the low-temperature hydrothermal treatment of iron-porphyrin-modified graphene and copper-chloride-loaded CNTs followed by high-temperature calcination, for use as efficient and stable electrocatalysts for the ORR. The optimized Fe/CuÀN-rGO/CNT catalyst exhibited higher ORR activity and superior stability, as compared to a commercial Pt/C catalyst in 0.1 mol · L À1 KOH solutions, and also demonstrates good stability in acidic electrolytes. These results suggest that additional doping of Cu ions into the Fe/N/C catalyst significantly promotes the catalyst ORR performance.

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“…One approach to increase its surface area is by 'dealloying' to create a porous structure. [10] Dealloying may also alter the electrocatalytic properties due to the ensemble, ligand, and strain effect. To explore these hypotheses, we dealloyed amorphous and quasicrystalline alloy and calibrated changes in electrocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Activated Porous Highly Enriched Platinum and Palladium Electrocatalysts from Dealloyed Noncrystalline Alloys for Enhanced Hydrogen Evolution

2020

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Modulation of activity of a quasicrystalline or amorphous matrix by selective dealloying of a less reactive metal is a trade-off between an activity increment due to enhanced electronic structure/surface area and an activity decrement due to an increase in crystallinity. We evaluate this trade-off in melt-spun ribbons of amorphous PtZr 4 and quasicrystalline PdZr 3 metallic glasses for the hydrogen evolution reaction (HER). Selective electrochemical dissolution of Zr generates highly porous, stable, predominantly Pt and Pd electrocatalysts and having three and eight times higher HER specific activity. Dealloyed Pt has two times higher specific HER activity than dealloyed Pd. The heat of mixing between Pt (Pd) and Zr is correlated to the extent of dealloying from PtZr 4 (PdZr 3) alloys. Dealloying glassforming element Zr enhances the activity of the resultant porous material due to the reduction in oxide layer formation and better optimized MÀ H bond strength. X-ray photoelectron spectroscopy analysis suggests that activity enhancement is due to Pt/Pd atoms gaining a partial negative charge leading to the promotion of H + absorption and an increase of HER activity upon dealloying. The present work also provides insight into the challenging search for a glass-former that does not have a debilitating effect on the electronic structure of the noble metals.

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Superior Catalysts for Oxygen Reduction Reaction Based on Porous Nanostars of a Pt, Pd, or Pt–Pd Alloy Shell Supported on a Gold Core

Cited by 28 publications

References 38 publications

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

Doping Copper Ions into an Fe/N/C Composite Promotes Catalyst Performance for the Oxygen Reduction Reaction

Activated Porous Highly Enriched Platinum and Palladium Electrocatalysts from Dealloyed Noncrystalline Alloys for Enhanced Hydrogen Evolution

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