CeO 2 surface oxygen vacancy concentration governs in situ free radical scavenging efficacy in polymer electrolytes

Panagiotis Trogadas; Javier Parrondo; Vijay Ramani

doi:10.1021/am3016069

CeO ₂ surface oxygen vacancy concentration governs in situ free radical scavenging efficacy in polymer electrolytes

Panagiotis Trogadas
, Javier Parrondo
, Vijay Ramani

Research output: Contribution to journal › Article › peer-review

228 Scopus citations

Abstract

Nonstoichiometric CeO ₂ and Ce _0.25Zr _0.75O ₂ nanoparticles with varying surface concentrations of Ce ³⁺ were synthesized. Their surface Ce ³⁺ concentration was measured by XPS, and their surface oxygen vacancy concentrations and grain size were estimated using Raman spectroscopy. The surface oxygen vacancy concentration was found to correlate well with grain size and surface Ce ³⁺ concentration. When incorporated into a Nafion polymer electrolyte membrane (PEM), the added nonstoichiometric ceria nanoparticles effectively scavenged PEM-degradation-inducing free radical reactive oxygen species (ROS) formed during fuel cell operation. A 3-fold increase in the surface oxygen vacancy concentration resulted in an order of magnitude enhancement in the efficacy of free radical ROS scavenging by the nanoparticles. Overall, the macroscopic PEM degradation mitigation rate was lowered by up to 2 orders of magnitude using nonstoichiometric ceria nanoparticles with high surface oxygen vacancy concentrations

Original language	English
Pages (from-to)	5098-5102
Number of pages	5
Journal	ACS Applied Materials and Interfaces
Volume	4
Issue number	10
DOIs	https://doi.org/10.1021/am3016069
State	Published - Oct 24 2012

Keywords

free radical scavenging
nonstoichiometric cerium oxide
PEM degradation
reactive oxygen species

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10.1021/am3016069

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title = "CeO 2 surface oxygen vacancy concentration governs in situ free radical scavenging efficacy in polymer electrolytes",

abstract = "Nonstoichiometric CeO 2 and Ce 0.25Zr 0.75O 2 nanoparticles with varying surface concentrations of Ce 3+ were synthesized. Their surface Ce 3+ concentration was measured by XPS, and their surface oxygen vacancy concentrations and grain size were estimated using Raman spectroscopy. The surface oxygen vacancy concentration was found to correlate well with grain size and surface Ce 3+ concentration. When incorporated into a Nafion polymer electrolyte membrane (PEM), the added nonstoichiometric ceria nanoparticles effectively scavenged PEM-degradation-inducing free radical reactive oxygen species (ROS) formed during fuel cell operation. A 3-fold increase in the surface oxygen vacancy concentration resulted in an order of magnitude enhancement in the efficacy of free radical ROS scavenging by the nanoparticles. Overall, the macroscopic PEM degradation mitigation rate was lowered by up to 2 orders of magnitude using nonstoichiometric ceria nanoparticles with high surface oxygen vacancy concentrations",

keywords = "free radical scavenging, nonstoichiometric cerium oxide, PEM degradation, reactive oxygen species",

author = "Panagiotis Trogadas and Javier Parrondo and Vijay Ramani",

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T1 - CeO 2 surface oxygen vacancy concentration governs in situ free radical scavenging efficacy in polymer electrolytes

AU - Trogadas, Panagiotis

AU - Parrondo, Javier

AU - Ramani, Vijay

PY - 2012/10/24

Y1 - 2012/10/24

N2 - Nonstoichiometric CeO 2 and Ce 0.25Zr 0.75O 2 nanoparticles with varying surface concentrations of Ce 3+ were synthesized. Their surface Ce 3+ concentration was measured by XPS, and their surface oxygen vacancy concentrations and grain size were estimated using Raman spectroscopy. The surface oxygen vacancy concentration was found to correlate well with grain size and surface Ce 3+ concentration. When incorporated into a Nafion polymer electrolyte membrane (PEM), the added nonstoichiometric ceria nanoparticles effectively scavenged PEM-degradation-inducing free radical reactive oxygen species (ROS) formed during fuel cell operation. A 3-fold increase in the surface oxygen vacancy concentration resulted in an order of magnitude enhancement in the efficacy of free radical ROS scavenging by the nanoparticles. Overall, the macroscopic PEM degradation mitigation rate was lowered by up to 2 orders of magnitude using nonstoichiometric ceria nanoparticles with high surface oxygen vacancy concentrations

AB - Nonstoichiometric CeO 2 and Ce 0.25Zr 0.75O 2 nanoparticles with varying surface concentrations of Ce 3+ were synthesized. Their surface Ce 3+ concentration was measured by XPS, and their surface oxygen vacancy concentrations and grain size were estimated using Raman spectroscopy. The surface oxygen vacancy concentration was found to correlate well with grain size and surface Ce 3+ concentration. When incorporated into a Nafion polymer electrolyte membrane (PEM), the added nonstoichiometric ceria nanoparticles effectively scavenged PEM-degradation-inducing free radical reactive oxygen species (ROS) formed during fuel cell operation. A 3-fold increase in the surface oxygen vacancy concentration resulted in an order of magnitude enhancement in the efficacy of free radical ROS scavenging by the nanoparticles. Overall, the macroscopic PEM degradation mitigation rate was lowered by up to 2 orders of magnitude using nonstoichiometric ceria nanoparticles with high surface oxygen vacancy concentrations

KW - free radical scavenging

KW - nonstoichiometric cerium oxide

KW - PEM degradation

KW - reactive oxygen species

UR - https://www.scopus.com/pages/publications/84867905722

U2 - 10.1021/am3016069

DO - 10.1021/am3016069

M3 - Article

AN - SCOPUS:84867905722

SN - 1944-8244

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EP - 5102

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

IS - 10

ER -

CeO ₂ surface oxygen vacancy concentration governs in situ free radical scavenging efficacy in polymer electrolytes

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