Title: Facet Impact of CuMn₂O₄ Spinel Nanocatalysts on Enhancement of the Oxygen Reduction Reaction in Alkaline Media

Abstract

Surface-structure engineering represents an attractive strategy to optimize the energy conversion performance of nanocatalysts using their deliberately controlled exposed facets. To further exploit the potential of non-PGM-based spinel catalysts for alkaline oxygen reduction reaction (ORR), a cathodic fuel cell reaction, we hereby report a strategy of ORR improvement by controlling the crystallographic facets of ultra-small CuMn₂O₄ spinel nanocatalysts through a developed colloidal synthesis approach. The synthesis of CuMn₂O₄ nanocrystals with morphological control relies on the design and selection of the Cu-/Mn-precursors with striking discrepancies in reaction kinetics. Following carbon loading and an annealing post-treatment of the as-synthesized nanocatalysts, the exclusively {101} facet-exposed CuMn₂O₄ spinel nano-octahedra exhibit improved electrocatalytic activity toward ORR in 1 M KOH, when compared to their spherical counterparts, exhibiting a mass activity (MA) of 37.6 A/g at 0.85 V. After 10,000 cycles of ORR durability test, the nano-octahedra still retain an MA of 24.5 A/g, which is twice that of the CuMn₂O₄ spinel nanospheres. Structural characterizations after durability testing indicate that the MA decay is likely associated with a decrease in the Mn³⁺ fraction and the emergence of Cu⁺ on CuMn₂O₄ nano-octahedral surfaces. Finally, as a paradigm, this synthesis approach could be extended to other Mn-based spinelmore » nanocatalysts with precise shape control, enabling us to understand and establish the relationship between the surface lattice/valence state and electrocatalytic properties.« less

Authors:

Zhou, Ming  ^[1];

• Search DOE PAGES for author "Zhou, Ming"
• Search DOE PAGES for ORCID "0000-0002-2708-0501"

Wang, Hongsen  ^[2];

• Search DOE PAGES for author "Wang, Hongsen"
• Search DOE PAGES for ORCID "0000-0001-7926-2895"

Zhang, Lihua  ^[3];

• Search DOE PAGES for author "Zhang, Lihua"
• Search DOE PAGES for ORCID "0000-0003-3331-2345"

Li, Can  ^[1];

• Search DOE PAGES for author "Li, Can"
• Search DOE PAGES for ORCID "0000-0001-8894-5110"

Kumbhar, Amar ^[4]; Abruña, Héctor D.  ^[2];

• Search DOE PAGES for author "Abruña, Héctor D."
• Search DOE PAGES for ORCID "0000-0002-3948-356X"

Fang, Jiye  ^[1]

• Search DOE PAGES for author "Fang, Jiye"
• Search DOE PAGES for ORCID "0000-0003-3703-3204"

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+ Show Author Affiliations

1. State Univ. of New York (SUNY), Binghamton, NY (United States)
2. Cornell Univ., Ithaca, NY (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
4. Univ. of North Carolina, Chapel Hill, NC (United States)

Publication Date:

Tue Oct 25 00:00:00 EDT 2022

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

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

OSTI Identifier:

1905227

Report Number(s):

BNL-223801-2022-JAAM
Journal ID: ISSN 2155-5435

Grant/Contract Number:  

SC0012704; SC0019445; DMR 1808383

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 12; Journal Issue: 21; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; nano-octahedron; spinel; ORR; alkaline media; CuMn2O4; catalysts; nanocrystals; redox reactions; transition metals