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Activating Mn3O4 by Morphology Tailoring for Oxygen Reduction Reaction
- Source :
- Electrochimica Acta. 205:38-44
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- Oxygen reduction reaction (ORR) is becoming increasingly important with the development of fuel cells and metal-air batteries. Manganese oxides have been one of the focuses of recent research for Pt-alternative ORR catalysts. However, the structure-activity relationships of manganese oxides have not been well studied or understood. In the present work, we report a new finding that there is a strong dependence of the ORR activity of Mn 3 O 4 on its morphology. By adopting different solvents in the wet-chemical synthesis, we are able to tailor the morphology of Mn 3 O 4 from nanoparticles (NP-L, 12.5 nm and NP-S, 5.95 nm) to nanorods (NR, exposure of Mn 3 O 4 (101)) and nanoflake (NF, exposure of Mn 3 O 4 (001)). Surprisingly, surface-specific activity of NF toward the ORR was found to be one order of magnitude higher than NP-L. The morphology-activity relationships of Mn 3 O 4 were further studied through a combination of electrochemical experiments and density functional theory (DFT) calculations. It was discovered that the formation of *OOH, concomitant with the first electron transfer, is the potential determining step, which is thermo-dynamically more facile on Mn 3 O 4 (001) than (101) plane. The underlying mechanism could be ascribed to the strong interaction between O 2 and Mn 3 O 4 (001) surface as indicated by the DFT calculations. The study enlarges our understanding of Mn 3 O 4 catalysis and provides clues for rational design of highly efficient transitional metal oxide electrocatalysts for the ORR.
- Subjects :
- Chemistry
General Chemical Engineering
Inorganic chemistry
Oxide
chemistry.chemical_element
02 engineering and technology
Manganese
010402 general chemistry
021001 nanoscience & nanotechnology
Electrochemistry
Electrocatalyst
01 natural sciences
0104 chemical sciences
Catalysis
Electron transfer
chemistry.chemical_compound
Transition metal
Nanorod
0210 nano-technology
Subjects
Details
- ISSN :
- 00134686
- Volume :
- 205
- Database :
- OpenAIRE
- Journal :
- Electrochimica Acta
- Accession number :
- edsair.doi...........1cd9c71b69762f00ff8b6e7fc3766901