In Situ Engineering of a Metal Oxide Protective Layer into Pt/Carbon Fuel-Cell Catalysts by Atomic Layer Deposition

Lee, Woo‐Jae; Bera, Susanta; Woo, Hyun‐Jae; Kim, Hyun Gu; Baek, Ji-Hu; Hong, Woongpyo; Park, Jung-Yeon; Oh, Seung‐Jeong; Kwon, Sun-Hong

doi:10.1021/acs.chemmater.2c00928

Cited by 15 publications

(10 citation statements)

References 47 publications

(79 reference statements)

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“…The cause of this is membrane deterioration by hydroxyl free radicals generated from the decomposition of H 2 O 2 formed by ORR on the cathode side of PEMFC. 1 When operating PEMFCs at high temperature/low humidity, more oxygen crossover occurs, and gas crossover because of the creation of pinholes in the membrane makes long-term use of PEMFCs difficult. 2 Figure 8a indicates the OCV hold condition test of Pt/C| NRE-212 and Pt/C+CZTO-1|Nafion-CZTO-1.0 MEA at 20% RH.…”

Section: Eis Analysismentioning

confidence: 99%

“…A PEMFC has been applied and developed for residential, military, and portable power sources. Recently, as an automobile engine system, it has been attracting much attention in the automobile industry as a friendly, eco-friendly, and energy-efficient device . A PEMFC has attracted much attention and anticipation for its advantages of being environmentally friendly and rapid and having high energy efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Cerium-Based Perovskite Mixed Metal Oxide as the Radical Scavenger for PEM Fuel Cells Operating under Low Humidity Conditions

Son

Shanmugam

2023

ACS Appl. Mater. Interfaces

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When the polymer electrolyte membrane fuel cell (PEMFC) is operated under low humidity, the proton conductivity decreases due to membrane dehydration, causing adverse effects on fuel cell performance. Introducing appropriate additives to the membrane and catalyst layer to prevent membrane degradation at low humidity brings significant performance improvements to proton exchange membrane fuel cells. We developed a perovskitestructured multi-metal oxide Ce 0.667 Zr 0.05 Ti 0.95 O 3-δ (CZTO) with high radical scavenging properties and good structural stability. The nanostructured ceramic CZTO is introduced into the membrane and cathode catalyst layer to improve the durability of the membrane electrode assembly. The Nafion-CZTO membrane exhibited maximum power densities of 1298 and 519 mW cm -2−2 at 100 and 20% relative humidity, respectively. The improved performance of Nafion-CZTO membranes over commercial Nafion membranes is due to the high proton conductivity and better radical scavenging properties of the CZTO additive. In addition, the expected positive effects of applying CZTO additives to the catalyst layer are verified by low charge transfer resistance and high electrochemical surface activity of the CZTO catalyst through electrochemical impedance spectroscopy and electrochemical surface area analyses.

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Section: Eis Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cerium-Based Perovskite Mixed Metal Oxide as the Radical Scavenger for PEM Fuel Cells Operating under Low Humidity Conditions

Son

Shanmugam

2023

ACS Appl. Mater. Interfaces

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“…Reducing the amount of Pt while improving the activity and stability of the catalysts is an efficient route to address these issues . Owing to its advantages of versatility and excellent controllability, ALD has become the method of choice for the synthesis of advanced Pt-based catalysts for fuel cell technologies, including proton-exchange-membrane fuel cells (PEMFCs), ,,,− solid-oxide fuel cells (SOFCs), ,,− and polymer electrolyte fuel cells. ,, Many studies have demonstrated that the ALD-grown Pt catalysts provide a higher Pt utilization efficiency in comparison with the commercial catalysts and the catalysts synthesized by other methods. Jiang et al deposited Pt films by two different techniques, i.e., ALD and sputtering, and investigated their performance as anode catalytic layers for SOFCs .…”

Section: Dimension Control and Applications Of Ald-grown Pt Nanostruc...mentioning

confidence: 99%

Dimension Control of Platinum Nanostructures by Atomic Layer Deposition: From Surface Chemical Reactions to Applications

Dinh

Nguyen

et al. 2023

Chem. Mater.

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For over 20 years, atomic layer deposition (ALD) of platinum (Pt) has gained significant achievements in the fabrication of a variety of Pt nanostructures for applications in different fields, including microelectronics, sensors, catalysis, and energy conversion, storage, and utilization devices. By relying on its unique self-saturating surface reactions with diverse precursor chemistries, tunable deposition conditions, and various surface engineering methods, ALD offers the capability of controlling the amount of deposited Pt at the atomic level precision and enables the fabrication of various low-dimensional nanostructures, such as single atoms, nanoclusters, core/shell nanoparticles, and ultrathin continuous films. These ALD-fabricated Pt nanostructures not only provide outstanding performances but also maximize the Pt usage efficiency that can address the cost-related issues of Pt. Nevertheless, to achieve a controllable deposition, it is important to acquire a deep understanding on the precursor chemistry, the surface reaction, nucleation, and growth mechanisms, as well as the influence of deposition conditions and surface engineering, which are the key factors that govern the growth of Pt. By reviewing the advances in Pt ALD since its inauguration with the focus on these factors as well as its potential applications, we expect that this article can provide the fundamentals of Pt ALD, which may serve as a guide to achieve a desired Pt nanostructure for a targeted application.

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“…Another steric protection strategy lies in encapsulating the active catalyst using a thin conductive (oxide) layer. Specifically, TiO 2 has been targeted and demonstrated to be effective in protecting platinum particles from agglomeration. , Increasing the metal–support interaction and the use of confinement strategies lead to a decrease in particle agglomeration.…”

Section: What Are the Dominant Degradation Pathways In Aqueous Electr...mentioning

confidence: 99%

“…Specifically, TiO 2 has been targeted and demonstrated to be effective in protecting platinum particles from agglomeration. 141,142 Increasing the metal− support interaction and the use of confinement strategies lead to a decrease in particle agglomeration.…”

Section: What Are the Dominant Degradation Pathways In Aqueous Electr...mentioning

confidence: 99%

Catalyst Stability in Aqueous Electrochemistry

2022

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The main challenges in catalysis are high activity, selectivity, cost efficiency, and stability. In industrial processes, stability in particular is of pressing concern, and its importance has become more and more acknowledged in academia. At the same time, the need for alternatives to replace fossil raw materials is omnipresent, and the electrification of synthetic processes is picking up in speed. New processes are being developed and novel materials are being tested, while assessing the stability of emerging catalysts can be time-consuming and frustrating but, at the same time, highly important. This problem is exacerbated by a clear lack of realistic stability measurements of new catalysts and an understanding of the key driving forces for the specific degradation pathway. In this perspective, deactivation processes in aqueous electrochemistry are selectively discussed and mitigation strategies are presented. A special focus is placed on the intrinsic material properties that react to the surrounding environment. The applied conditions not only predefine the product spectrum and activity of the catalytic material but also strongly influence the catalyst’s stability. We review various concepts to increase the stability, for instance, by tailoring the coordination environment around the active center, and highlight the importance of the support material. The presented concepts together with stability descriptors serve as important guidelines toward stable and sustainable catalyst systems.

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In Situ Engineering of a Metal Oxide Protective Layer into Pt/Carbon Fuel-Cell Catalysts by Atomic Layer Deposition

Cited by 15 publications

References 47 publications

Cerium-Based Perovskite Mixed Metal Oxide as the Radical Scavenger for PEM Fuel Cells Operating under Low Humidity Conditions

Cerium-Based Perovskite Mixed Metal Oxide as the Radical Scavenger for PEM Fuel Cells Operating under Low Humidity Conditions

Dimension Control of Platinum Nanostructures by Atomic Layer Deposition: From Surface Chemical Reactions to Applications

Catalyst Stability in Aqueous Electrochemistry

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