Title: Rh and Rh Alloy Nanoparticles as Highly Active H₂ Oxidation Catalysts for Alkaline Fuel Cells

Abstract

When moving from acidic to alkaline media, non-Pt-group metal catalysts can be used as the oxygen reduction catalyst, because of their high activity and stability. However, in alkaline electrolytes, we meet another challenge: slower H₂ oxidation kinetics on platinum group metals, relative to acidic electrolytes. We require new robust anode catalysts to enhance H₂ oxidation kinetics in alkaline anion exchange membrane fuel cells (AEMFCs). In this Letter, carbon-supported Rh and Rh alloy nanoparticles such as Pt₇Rh₃/C, Ir₉Rh₁/C, Rh₉Ru₁/C and Rh₉Pd₁/C were found to be highly active hydrogen oxidation and evolution catalysts in alkaline media. A size effect was observed for Rh/C, i.e., the hydrogen oxidation reaction (HOR) activity significantly increased on Rh nanoparticles, relative to bulk Rh. A synergistic effect was noted for the hydrogen oxidation on PtRh and IrRh alloy catalysts. These Rh and Rh alloy nanoparticles outperformed Ir/C and Pt/C as electrocatalysts. In particular, Rh/C with an average particle size of ca. 2 nm was identified to be the best HOR catalyst among all catalysts studied, in terms of its mass activity, while Pt₇Rh₃/C outperformed other studied catalysts, in terms of its specific activity and exchange current density. Ir9Rh1/C was found to be the most effective electrocatalyst amongmore » all studied Ir alloy nanoparticles. These Rh and Rh alloy catalysts could be employed as highly active H₂ electrocatalysts in anion exchange membrane fuel cells.« less

Authors:

Wang, Hongsen  ^[1];

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

Abruña, Héctor D.  ^[1]

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

---

+ Show Author Affiliations

1. Cornell Univ., Ithaca, NY (United States)

Publication Date:

Wed Apr 24 00:00:00 EDT 2019

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Alkaline-Based Energy Solutions (CABES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

Contributing Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Alkaline-Based Energy+B11:C29 Solutions (CABES); Cornell Univ., Ithaca, NY (United States)

OSTI Identifier:

1566572

Grant/Contract Number:  

SC0019445

Resource Type:

Accepted Manuscript

Journal Name:

ACS Catalysis

Additional Journal Information:

Journal Volume: 9; Journal Issue: 6; Journal ID: ISSN 2155-5435

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; catalysis (heterogeneous); electrocatalysis; hydrogen and fuel cells; charge transport; membranes; water; materials and chemistry by design; synthesis (novel materials)