Core–shell catalysts consisting of nanoporous cores for oxygen reduction reaction

Shao, Minhua; Smith, Brandon H.; Guerrero, Sandra; Protsailo, Lesia; Su, Dong; Kaneko, Keiichi; Odell, Jonathan H.; Humbert, Michael P.; Sasaki, Kotaro; Marzullo, Jesse Michael; Darling, Robert M.

doi:10.1039/c3cp52252k

Cited by 32 publications

(44 citation statements)

References 48 publications

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“…In addition to the Pt precursor, citric acid was also included in the Pt precursor solution to minimize the formation of Pt clusters. 12,22 After the reaction was complete, typically in 30 minutes, catalysts were filtered and rinsed with ultrapure water (Milli-Q UVplus water). The resulting catalyst powder, denoted as Pt/Pd/C, was dried in a vacuum at 60…”

Section: Methodsmentioning

confidence: 99%

Fuel Cell Performance of Palladium-Platinum Core-Shell Electrocatalysts Synthesized in Gram-Scale Batches

Khateeb¹,

Guerreo²,

et al. 2016

J. Electrochem. Soc.

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This paper presents the performance of palladium-platinum core-shell catalysts (Pt/Pd/C) for oxygen reduction synthesized in gramscale batches in both liquid cells and polymer-electrolyte membrane fuel cells. Core-shell catalyst synthesis and characterization, ink fabrication, and cell assembly details are discussed. The Pt mass activity of the Pt/Pd core-shell catalyst was 0.95 A mg −1 at 0.9 V measured in liquid cells (0.1 M HClO 4 ), which was 4.8 times higher than a commercial Pt/C catalyst. The performances of Pt/Pd/C and Pt/C in large single cells (315 cm 2 ) were assessed under various operating conditions. The core-shell catalyst showed consistently higher performance than commercial Pt/C in fuel cell testing. A 20-60 mV improvement across the whole current density range was observed on air. Sensitivities to temperature, humidity, and gas composition were also investigated and the core-shell catalyst showed a consistent benefit over Pt under all conditions. However, the 4.8 times activity enhancement predicated by liquid cell measurements was not fully realized in fuel cells. Polymer electrolyte membrane (PEM) fuel cells face hurdles to commercialization in automotive applications in part because of the high cost of Pt-based catalysts used in the anode and cathode.

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Section: Methodsmentioning

confidence: 99%

Fuel Cell Performance of Palladium-Platinum Core-Shell Electrocatalysts Synthesized in Gram-Scale Batches

Khateeb¹,

Guerreo²,

et al. 2016

J. Electrochem. Soc.

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“…5,19,20 The Pt mass activity of Pd@Pt/C was improved by two times with the assistance of citric acid in the synthesis process. 20 It should be noted that the undisclosed additive in Refs.…”

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confidence: 98%

“…1). 5 The mechanism underlying this observation is that the SLRR process involves the electron transfer from the substrate (Pd in this case) to PtCl 4 2− ions, rather than direct electron exchange = These authors contributed equally to this work. * Electrochemical Society Student Member.…”

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confidence: 99%

“…4 For some core-shell catalysts, the Pt mass activities can be 10 times higher than that of Pt/C measured by RDE. 5,16,17 Ideally, a uniform Pt monolayer is deposited on the core after all the Cu atoms are replaced. However, our previous study demonstrated that Pt clusters rather than a uniform Pt shell are formed on Pd nanoparticles (Fig.…”

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confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] As only surface atoms actively participate in the oxygen reduction reaction (ORR), this approach can significantly enhance the utilization of Pt, i.e., lower the ratio of unexposed Pt atoms wasted inside of the particles. The core-shell structure can also provide significant benefits in cost reduction since the core is less expensive than Pt.…”

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The Role of Citric Acid in Perfecting Platinum Monolayer on Palladium Nanoparticles during the Surface Limited Redox Replacement Reaction

Zhu

Yue

Qin

et al. 2016

J. Electrochem. Soc.

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Cu-mediated-Pt-displacement method that involves the displacement of an underpotentially deposited (UPD) Cu monolayer by Pt has been extensively studied to prepare core-shell catalysts. It has been found that Pt clusters instead of a uniform Pt monolayer were formed in the gram batch synthesis. With a suitable surfactant, such as citric acid, the Pt shell could be much more uniform. In this study, the role of citric acid in controlling the Cu-Pt displacement reaction kinetics was studied by electrochemical techniques and theoretical approaches. It was found that citric acid strongly adsorbed on Pd, Pt, Cu/Pd, and Pt/Pd surfaces, especially in the double layer region in acid solutions. The strong adsorption of citric acid slowed down the Cu-Pt displacement reaction. The main characteristics of such strong interaction most likely arises from the OH groups in the citric acid molecule according to the molecular dynamics simulation results.

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Highly Stable Pt‐Based Ternary Systems for Oxygen Reduction Reaction in Acidic Electrolytes

Kim

Hong

Lee

et al. 2020

Advanced Energy Materials

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electrolytes, have received considerable attention. PAFCs are best suited for stationary power with combined heat and power, and have high overall efficiency and long system lifetimes, while PEMFCs are typically used in automobiles and portable electronics because of their compact size, light weight, high power density, and low operating temperature. [5,6] However, critical components in both PAFCs and PEMFCs, including electrodes, membranes, and catalysts, are still being intensively developed to resolve serious issues in performance, cost, and durability. The latest development plan for fuel cells from the U.S. Department of Energy suggests that more durable and stable catalysts for PAFCs will be necessary to ensure prolonged operation with less cost. [7] Also, the durability and cost of PEMFCs must be improved for commercialization in lightduty vehicles (Figure 1a). This is due in part to costly Pt catalysts, which comprise a significant fraction of the total production cost of PEMFCs (Figure 1b). [8] Overall, more highly efficient and robust Pt-based catalysts are essential to ensure wider use of clean and sustainable hydrogen fuel cell systems.

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Core–shell catalysts consisting of nanoporous cores for oxygen reduction reaction

Cited by 32 publications

References 48 publications

Fuel Cell Performance of Palladium-Platinum Core-Shell Electrocatalysts Synthesized in Gram-Scale Batches

Fuel Cell Performance of Palladium-Platinum Core-Shell Electrocatalysts Synthesized in Gram-Scale Batches

The Role of Citric Acid in Perfecting Platinum Monolayer on Palladium Nanoparticles during the Surface Limited Redox Replacement Reaction

Highly Stable Pt‐Based Ternary Systems for Oxygen Reduction Reaction in Acidic Electrolytes

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