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Impact of controlling the crystallinity on bifunctional electrocatalytic performances toward methanol oxidation and oxygen reduction in binary Pd-Cr solid solution
- Title
- Impact of controlling the crystallinity on bifunctional electrocatalytic performances toward methanol oxidation and oxygen reduction in binary Pd-Cr solid solution
- Authors
- Jin D.; Lee Y.; Kim I.Y.; Lee C.; Kim M.H.
- Ewha Authors
- 이종목; 이영미; 김명화; 김인영
- SCOPUS Author ID
- 이종목; 이영미; 김명화; 김인영
- Issue Date
- 2023
- Journal Title
- Journal of Materials Chemistry A
- ISSN
- 2050-7488
- Citation
- Journal of Materials Chemistry A vol. 11, no. 30, pp. 16243 - 16254
- Publisher
- Royal Society of Chemistry
- Indexed
- SCIE; SCOPUS
- Document Type
- Article
- Abstract
- Understanding the relationship between crystallographic structure and electrocatalytic performance is important to successfully design an efficient electrocatalyst. With finely controlled thermal H2-reduction condition, herein, binary Pd-Cr nanofibers were fabricated as a bifunctional electrocatalyst toward both methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) for direct methanol fuel cells (DMFCs), retaining the distinct crystalline characters. The Pd-Cr nanofiber series was synthesized through the thermal reduction of single-phase PdxCr1−xOy nanofibers in the presence of a hydrogen gas flow. The resulting nanofibers exhibited different levels of crystallinity, which were significantly influenced by the reduction temperature. At a temperature of 350 °C, the Pd-Cr nanofibers were synthesized in an amorphous state, while the nanofibers reduced at temperatures above 500 °C gradually crystallized into a face-centered cubic (fcc) structure. Notably, the amorphous Pd-Cr nanofibers exhibited superior alkaline MOR performance, including high mass activity and a small Tafel slope, compared to the other crystalline counterparts in the Pd-Cr series. In situ Raman spectroscopy and CO stripping measurements further confirmed the remarkable catalytic activity and stability of the amorphous nanofibers, outperforming commercial Pd/C catalysts. Similarly, for alkaline ORR, the amorphous Pd-Cr nanofibers demonstrated superior catalytic performance, with a higher onset potential and positive half-wave potential, compared to the crystalline counterparts. Additionally, the amorphous catalyst exhibited improved resistance against agglomeration and methanol crossover issues, which are commonly observed with commercial Pt/C catalysts, serving as a benchmark for alkaline ORR. Therefore, this study highlights the facile strategy of designing optimal electrocatalysts for DMFCs by controlling the novel crystallographic structure within the binary Pd-Cr solid solution. © 2023 The Royal Society of Chemistry.
- DOI
- 10.1039/d3ta02782a
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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