Title: Mn- and N- doped carbon as promising catalysts for oxygen reduction reaction: Theoretical prediction and experimental validation

Abstract

Development of platinum group metal (PGM)-free as well as iron-free electrocatalysts is imperative to achieve low-cost and long-term durability of polymer electrolyte membrane fuel cells. Here in this paper, we combined computational and experimental studies to investigate the mechanism, activity, and durability of Mn and N co-doped carbon (denoted as Mn-N-C) as promising catalysts for oxygen reduction reaction (ORR) in challenging acid medium. The first-principles density functional theory calculations predict that it is favorable for O₂ to be reduced into H₂O via four-electron pathway on MnN₄ sites embedded in carbon layer. Using the reaction energies calculated from DFT, microkinetic analysis predicts that the MnN₄ sites could catalyze ORR with a half-wave potential only 60 mV lower than that of Pt (111) and 80 mV lower than that of the FeN₄ sites embedded in carbon layer, assuming the same density of active sites in the catalysts. Motivated by the computational prediction, we synthesized a Mn-N-C catalyst using a polymer (i.e., polyaniline-PANI) hydrogel precursors via a high temperature approach. Structural characterization indicates that atomically dispersed Mn sites coordinated with N are very likely formed in the catalyst. Electrochemical measurements show that the synthesized Mn-N-C catalyst can promote four-electron ORR with a catalyticmore » activity in acids comparable to that of the Fe-N-C catalyst prepared using the same procedure. More importantly, the Mn-N-C catalyst exhibits superior potential cyclic stability, only losing 20 mV after 10000 cycles (0.6 to 1.0 V in O₂ saturated electrolyte). In comparison, the Fe-N-C catalyst would loss 80 mV after only 5000 cycles under the same testing conditions. Our computational and experimental results strongly suggest that the Mn and N co-doped carbon could be promising high-performance catalysts for ORR in acidic medium.« less

Authors:

Liu, Kexi ^[1]; Qiao, Zhi ^[2]; Hwang, Sooyeon ^[3]; Liu, Zhenyu ^[1]; Zhang, Hanguang ^[2]; Su, Dong ^[3]; Xu, Hui  ^[4];

• Search DOE PAGES for author "Xu, Hui"
• Search DOE PAGES for ORCID "0000-0001-6829-7187"

Wu, Gang  ^[2];

• Search DOE PAGES for author "Wu, Gang"
• Search DOE PAGES for ORCID "0000-0003-4956-5208"

Wang, Guofeng  ^[1]

• Search DOE PAGES for author "Wang, Guofeng"
• Search DOE PAGES for ORCID "0000-0001-8249-4101"

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+ Show Author Affiliations

1. Univ. of Pittsburgh, PA (United States)
2. Univ. at Buffalo, the State Univ. of New York, NY (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States)
4. Giner Inc., Newton, MA (United States)

Publication Date:

Tue Oct 16 00:00:00 EDT 2018

Research Org.:

Giner, Inc., Newton, MA (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1886835

Alternate Identifier(s):

OSTI ID: 1480960

Report Number(s):

BNL-209359-2018-JAAM
Journal ID: ISSN 0926-3373; 10124

Grant/Contract Number:  

EE0008075; CBET-1804534; CMMI-1662615; CBET- 1604392; ACI-1053575; SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Applied Catalysis. B, Environmental

Additional Journal Information:

Journal Volume: 243; Journal ID: ISSN 0926-3373

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; 36 MATERIALS SCIENCE; Oxygen reduction reaction; Density functional theory; Microkinetic analysis; Mn-N4active site; Polymer hydrogel; oxygen reduction reaction; density functional theory; microkinetic analysis; Mn-N4 active site; polymer hydrogen