Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

Lykhach, Yaroslava; Bruix, Albert; Fabris, Stefano; Potin, Valérie; Matolı́nová, Iva; Matolín, Vladimı́r; Libuda, Jörg; Neyman, Konstantin M.

doi:10.1039/c7cy00710h

Cited by 89 publications

(92 citation statements)

References 159 publications

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“…Pt−O−Ce bond was observed at 71.9 eV clarified by Mori et al ., which was also similar to the reported Ru‐O−Ce bond . Pt−O−Ce bonds in C/PBI/Pt@CeO x were supposed to be formed during the hydrothermal process, agreeing well with previous report . The partially ionized Pt was beneficial for boosting the stability of Pt electrocatalyst since partial ionization made Pt nanoparticles difficult to coalesce/aggregate .…”

Section: Resultssupporting

confidence: 90%

“…[19] PtÀOÀCe bonds in C/PBI/ Pt@CeO x were supposed to be formed during the hydrothermal process, agreeing well with previous report. [14] The partially ionized Pt was beneficial for boosting the stability of Pt electrocatalyst since partial ionization made Pt nanoparticles difficult to coalesce/aggregate. [16] It's worth noting that increment in Ce(III) content indicated that more Pt atoms were ionized at the interfaces and higher oxygen vacancy of CeO x was obtained.…”

Section: Resultsmentioning

confidence: 99%

“…However, sacrifice in electrocatalytic activity was inevitable in these previous studies on account of partial coverage of Pt active sites. [12] Recently, cerium dioxide (CeO 2 ) was introduced into Pt electrocatalyst to promote the CO tolerance, which is capable of offering hydroxyl groups directly reacting with the adsorbed CO species verified by Chu et al [13] Also, support material for Pt, CeO 2 was systematically summarized and reported by Lykhach et al [14] due to the strong interaction between Pt and CeO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Luo

Yang

et al. 2018

ChemElectroChem

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High and stable catalytic activity for the methanol oxidation reaction (MOR) and CO tolerance are essential for anodic electrocatalysts in direct methanol fuel cells (DMFCs). Here, we report a new method to simultaneously boost the CO tolerance as well as MOR stability of a Pt electrocatalyst by decoration with cerium oxide (CeOx). Detailed mechanistic investigations revealed that CeOx decoration can significantly improve the MOR stability of the Pt electrocatalyst due to the formation of Pt−O−Ce bonds ascribed to the high number of oxygen vacancies of CeOx. The simultaneously improved CO anti‐poisoning property of the CeOx decorated Pt electrocatalyst is resulting from Ce(OH)3, which is formed by the adsorption of water to CeOx. Ce(OH)3 could accelerate the formation of Pt(OH)ads species to recover CO poisoned Pt nanoparticles. At the same time, the CO species could also be oxidized by the lattice oxygen from CeOx. The fuel cell performance of the CeOx decorated Pt electrocatalyst is therefore higher than that of bare Pt electrocatalyst.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Luo

Yang

et al. 2018

ChemElectroChem

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“…Highly dispersed platinum nanoparticles (NPs) deposited on oxide supports are commonly used as the active components of catalysts for practically important processes, such as neutralization of harmful gases in automobile converters, reactions in fuel cells, preferential oxidation of carbon monoxide (PROX) reaction, and CO oxidation …”

Section: Introductionmentioning

confidence: 99%

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

et al. 2018

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The pulsed laser ablation (PLA) in alcohol and water media was employed to prepare Pt and CeO2 PLA‐nanoparticles of different sizes and degrees of defectiveness. Interactions of metallic platinum and ceria particles were studied using the thermal activation of Pt–CeO2 mechanical mixtures in the CO+O2 reaction medium or O2 atmosphere. The thermal activation resulted in oxidized Pt2+/Pt4+ states of platinum in the surface solid solutions PtCeOx and/or PtOx clusters. Catalysts formed after calcination of the PLA‐ablated Pt–CeO2 mixtures in oxygen at 450–600 °C revealed CO conversion at very low temperatures up to 70 % depending on the conditions of PLA particles preparation and thermal activation of Pt–CeO2 mechanical mixture.

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“…Interestingly, although the Pt 2+ was found to be thermally and chemically stable, it is apparently inactive for the dissociation of H 2 17 , and thus ineffective for hydrogenation reactions. A full review of the findings was recently published 18 , but in general, the authors conclude that Pt 2+ cations do not interact strongly with adsorbates, and that subnano Pt nanoparticles are likely responsible for catalytic activity arising in this system. 2+ clearly dominates, and is very stable, when the ceria support has a high step density.…”

mentioning

confidence: 99%

Unravelling single atom catalysis: The surface science approach

Parkinson

2017

Chinese Journal of Catalysis

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Understanding the fundamental mechanisms of single-atom catalysis (SAC) is important to design systems with improved performance and stability. This is problematic, however, because singleatom active sites are extremely difficult to characterize with existing experimental techniques. Over the last 40 years, surface science has provided the fundamental insights to understand heterogeneous catalysis, but model systems in which metal atoms are stable on well-characterized metal-oxide substrates at reaction temperatures are scarce. In this perspective, I discuss what is already known about isolated metal atoms adsorbed on model metal-oxide surfaces, and how this information can be used to understand SAC. A key issue is that, although the highly-idealised model systems studied in surface science may not be representative of a real working catalyst, they do very much resemble what can be calculated using state-of-the-art theoretical modelling. Thus, surface science offers an opportunity to rigorously benchmark the theoretical approach to modelling SAC in future. Perhaps more excitingly, several groups have developed model systems where metal adatoms remain stable at elevated temperatures. To date however, there has been no clear demonstration of catalytic activity. The perspective closes with a brief discussion of the prospect for STM experiments under realistic reaction conditions. Main TextThe rapidly emerging field of single-atom catalysis (SAC) aims to slash the precious metal loading in heterogeneous catalysts by replacing metal nanoparticles with so-called "single-atom" active sites 1 . While there are many reports of active SAC systems, the topic remains somewhat controversial because it is very difficult to characterize a system based on single atoms, and to distinguish between these and subnano particles 2 . In practice, most groups use aberration-corrected transmission electron microscopy (TEM) to demonstrate the atomic dispersion, sometimes supplemented by XANES, which can rule out significant metal-metal bonding 1 . The activity of the catalyst is then tested, and although some mechanistic information can be drawn by in-situ techniques such as IRAS, the catalytic mechanism is proposed largely on the basis of theoretical calculations. Such calculations are based on an idealised model of the system, in which both the support structure and active site geometry are assumed. Thus, a one-to-one correspondence between the experimental and theoretical results is difficult to prove.Traditionally, surface science has provided mechanistic information to understand heterogeneous catalysis. The idea is to strip away the complexity of a real catalyst and study well-defined singlecrystal samples in a highly-controlled ultrahigh vacuum (UHV) environment. This way, the adsorption of individual reactants can be studied in detail, and an understanding of the basic interactions can be built up. The downside of the approach is that the highly idealised model system may not be as representative of the real catalyst as o...

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Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

Cited by 89 publications

References 159 publications

Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Unravelling single atom catalysis: The surface science approach

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Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

Cited by 89 publications

References 159 publications

Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Insight Observation of Simultaneously Enhanced CO Tolerance and Stability of Pt Electrocatalysts Decorated with Oxygen Vacancy Rich Cerium Oxide

Transformation of a Pt–CeO2 Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation

Unravelling single atom catalysis: The surface science approach

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Product

Resources

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Transformation of a Pt–CeO₂ Mechanical Mixture of Pulsed‐Laser‐Ablated Nanoparticles to a Highly Active Catalyst for Carbon Monoxide Oxidation