Enhanced catalytic activity toward O2 reduction on Pt-modified La1-xSrxCo1-yFeyO3-δ cathode: A combination study of first-principles calculation and experiment

Wenqiang Yang; Zhenbin Wang; Zhiquan Wang; Zhenghui Yang; Changrong Xia; Ranran Peng; Xiaojun Wu; Yalin Lu

doi:10.1021/am505900g

Enhanced catalytic activity toward O₂ reduction on Pt-modified La_1-xSr_xCo_1-yFe_yO_3-δ cathode: A combination study of first-principles calculation and experiment

Wenqiang Yang, Zhenbin Wang, Zhiquan Wang, Zhenghui Yang, Changrong Xia, Ranran Peng^*, Xiaojun Wu, Yalin Lu

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

30 Citations (Scopus)

Abstract

Using the first-principles calculation and the electronic conductivity relaxation (ECR) experimental technique, we investigated the adsorption and dissociation behaviors of O₂ on Pt-modified La_0.625Sr_0.375Co_0.25Fe_0.75O_3-δ (LSCF) surface. Toward the O₂ reduction, the calculation results show that the perfect LSCF (100) surface is catalytically less active than both the defective (100) surface and the perfect (110) surface. O₂ molecule can weakly adsorb on the perfect LSCF (100) surface with a small adsorption energy of about -0.30 eV, but the dissociation energy barrier of the O₂ molecule is about 1.33-1.43 eV. Doping of Pt cluster on the LSCF (100) surface can remarkably enhance its catalytic activity. The adsorption energies of O₂ molecules become -1.16 and -1.89 eV for the interfacial Fe_int site and the Pt_bri bridge site of Pt₄-cluster, respectively. Meanwhile, the dissociation energy barriers are reduced to 0.37 and 0.53 eV, respectively. The migration energy barrier of the dissociated oxygen from the interfacial Pt to the LSCF surface is 0.66 eV, and it is 2.58 eV from the top site of the Pt cluster to the interfacial Pt site, suggesting that it is extremely difficult for oxygen to migrate over the Pt cluster. The Bader charge analysis results further indicate that the charges transferring from Pt cluster to LSCF surface promote the adsorption and dissociation of O₂ molecules. Experimentally, a dramatic decrease of the surface oxygen exchange relaxation time was observed on Pt-modified LSCF cathode, with a chemical surface exchange coefficient increased from 6.05 × 10^-5 cm/s of the bare LSCF cathode to 4.04 × 10^-4 cm/s of the Pt-modified LSCF cathode, agreeing very well with our theoretical predictions. © 2014 American Chemical Society.

Original language	English
Pages (from-to)	21051-21059
Journal	ACS Applied Materials and Interfaces
Volume	6
Issue number	23
DOIs	https://doi.org/10.1021/am505900g
Publication status	Published - 10 Dec 2014
Externally published	Yes

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Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

Research Keywords

density functional theory
LSCF
oxygen reduction
Pt modification
solid oxide fuel cells

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@article{ea948036eb7c48bf8209e48784ae429a,

title = "Enhanced catalytic activity toward O2 reduction on Pt-modified La1-xSrxCo1-yFeyO3-δ cathode: A combination study of first-principles calculation and experiment",

abstract = "Using the first-principles calculation and the electronic conductivity relaxation (ECR) experimental technique, we investigated the adsorption and dissociation behaviors of O2 on Pt-modified La0.625Sr0.375Co0.25Fe0.75O3-δ (LSCF) surface. Toward the O2 reduction, the calculation results show that the perfect LSCF (100) surface is catalytically less active than both the defective (100) surface and the perfect (110) surface. O2 molecule can weakly adsorb on the perfect LSCF (100) surface with a small adsorption energy of about -0.30 eV, but the dissociation energy barrier of the O2 molecule is about 1.33-1.43 eV. Doping of Pt cluster on the LSCF (100) surface can remarkably enhance its catalytic activity. The adsorption energies of O2 molecules become -1.16 and -1.89 eV for the interfacial Feint site and the Ptbri bridge site of Pt4-cluster, respectively. Meanwhile, the dissociation energy barriers are reduced to 0.37 and 0.53 eV, respectively. The migration energy barrier of the dissociated oxygen from the interfacial Pt to the LSCF surface is 0.66 eV, and it is 2.58 eV from the top site of the Pt cluster to the interfacial Pt site, suggesting that it is extremely difficult for oxygen to migrate over the Pt cluster. The Bader charge analysis results further indicate that the charges transferring from Pt cluster to LSCF surface promote the adsorption and dissociation of O2 molecules. Experimentally, a dramatic decrease of the surface oxygen exchange relaxation time was observed on Pt-modified LSCF cathode, with a chemical surface exchange coefficient increased from 6.05 × 10-5 cm/s of the bare LSCF cathode to 4.04 × 10-4 cm/s of the Pt-modified LSCF cathode, agreeing very well with our theoretical predictions. {\textcopyright} 2014 American Chemical Society.",

keywords = "density functional theory, LSCF, oxygen reduction, Pt modification, solid oxide fuel cells",

author = "Wenqiang Yang and Zhenbin Wang and Zhiquan Wang and Zhenghui Yang and Changrong Xia and Ranran Peng and Xiaojun Wu and Yalin Lu",

note = "Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].",

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day = "10",

doi = "10.1021/am505900g",

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volume = "6",

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Enhanced catalytic activity toward O₂ reduction on Pt-modified La_1-xSr_xCo_1-yFe_yO_3-δ cathode: A combination study of first-principles calculation and experiment. / Yang, Wenqiang; Wang, Zhenbin; Wang, Zhiquan et al.
In: ACS Applied Materials and Interfaces, Vol. 6, No. 23, 10.12.2014, p. 21051-21059.

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

TY - JOUR

T1 - Enhanced catalytic activity toward O2 reduction on Pt-modified La1-xSrxCo1-yFeyO3-δ cathode

T2 - A combination study of first-principles calculation and experiment

AU - Yang, Wenqiang

AU - Wang, Zhenbin

AU - Wang, Zhiquan

AU - Yang, Zhenghui

AU - Xia, Changrong

AU - Peng, Ranran

AU - Wu, Xiaojun

AU - Lu, Yalin

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

PY - 2014/12/10

Y1 - 2014/12/10

N2 - Using the first-principles calculation and the electronic conductivity relaxation (ECR) experimental technique, we investigated the adsorption and dissociation behaviors of O2 on Pt-modified La0.625Sr0.375Co0.25Fe0.75O3-δ (LSCF) surface. Toward the O2 reduction, the calculation results show that the perfect LSCF (100) surface is catalytically less active than both the defective (100) surface and the perfect (110) surface. O2 molecule can weakly adsorb on the perfect LSCF (100) surface with a small adsorption energy of about -0.30 eV, but the dissociation energy barrier of the O2 molecule is about 1.33-1.43 eV. Doping of Pt cluster on the LSCF (100) surface can remarkably enhance its catalytic activity. The adsorption energies of O2 molecules become -1.16 and -1.89 eV for the interfacial Feint site and the Ptbri bridge site of Pt4-cluster, respectively. Meanwhile, the dissociation energy barriers are reduced to 0.37 and 0.53 eV, respectively. The migration energy barrier of the dissociated oxygen from the interfacial Pt to the LSCF surface is 0.66 eV, and it is 2.58 eV from the top site of the Pt cluster to the interfacial Pt site, suggesting that it is extremely difficult for oxygen to migrate over the Pt cluster. The Bader charge analysis results further indicate that the charges transferring from Pt cluster to LSCF surface promote the adsorption and dissociation of O2 molecules. Experimentally, a dramatic decrease of the surface oxygen exchange relaxation time was observed on Pt-modified LSCF cathode, with a chemical surface exchange coefficient increased from 6.05 × 10-5 cm/s of the bare LSCF cathode to 4.04 × 10-4 cm/s of the Pt-modified LSCF cathode, agreeing very well with our theoretical predictions. © 2014 American Chemical Society.

AB - Using the first-principles calculation and the electronic conductivity relaxation (ECR) experimental technique, we investigated the adsorption and dissociation behaviors of O2 on Pt-modified La0.625Sr0.375Co0.25Fe0.75O3-δ (LSCF) surface. Toward the O2 reduction, the calculation results show that the perfect LSCF (100) surface is catalytically less active than both the defective (100) surface and the perfect (110) surface. O2 molecule can weakly adsorb on the perfect LSCF (100) surface with a small adsorption energy of about -0.30 eV, but the dissociation energy barrier of the O2 molecule is about 1.33-1.43 eV. Doping of Pt cluster on the LSCF (100) surface can remarkably enhance its catalytic activity. The adsorption energies of O2 molecules become -1.16 and -1.89 eV for the interfacial Feint site and the Ptbri bridge site of Pt4-cluster, respectively. Meanwhile, the dissociation energy barriers are reduced to 0.37 and 0.53 eV, respectively. The migration energy barrier of the dissociated oxygen from the interfacial Pt to the LSCF surface is 0.66 eV, and it is 2.58 eV from the top site of the Pt cluster to the interfacial Pt site, suggesting that it is extremely difficult for oxygen to migrate over the Pt cluster. The Bader charge analysis results further indicate that the charges transferring from Pt cluster to LSCF surface promote the adsorption and dissociation of O2 molecules. Experimentally, a dramatic decrease of the surface oxygen exchange relaxation time was observed on Pt-modified LSCF cathode, with a chemical surface exchange coefficient increased from 6.05 × 10-5 cm/s of the bare LSCF cathode to 4.04 × 10-4 cm/s of the Pt-modified LSCF cathode, agreeing very well with our theoretical predictions. © 2014 American Chemical Society.

KW - density functional theory

KW - LSCF

KW - oxygen reduction

KW - Pt modification

KW - solid oxide fuel cells

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U2 - 10.1021/am505900g

DO - 10.1021/am505900g

M3 - RGC 21 - Publication in refereed journal

SN - 1944-8244

VL - 6

SP - 21051

EP - 21059

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

IS - 23

ER -