TY - JOUR
T1 - The effect of Mn addition on the promotion of oxygen reduction reaction performance for PtCo/C catalysts
AU - Hsu, Shu Ping
AU - Liu, Chen Wei
AU - Chen, Hong Shuo
AU - Chen, Tsan Yao
AU - Lai, Chien Ming
AU - Lee, Chih Hao
AU - Lee, Jyh Fu
AU - Chan, Ting Shan
AU - Tsai, Li Duan
AU - Wang, Kuan Wen
N1 - Funding Information:
This work was supported by the National Science Council of Taiwan under contract no. NSC-101-2221-E-008-042 and 101-2120-M-007-013 . The authors also gratefully acknowledge the financial support granted by the NCU-ITRI Joint Research Center under Project No. 1001163 .
PY - 2013
Y1 - 2013
N2 - The effect of Mn addition on the promotion of oxygen reduction reaction (ORR) performance for PtCo/C catalysts is investigated. The structures, surface compositions, chemical compositions, local structural parameters including coordination numbers and bond distances, morphologies and electrochemical properties of prepared catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectrometer (ICP-AES), extended X-ray absorption fine structure (EXAFS), high resolution transmission electron microscopy (HRTEM) and rotating disk electrode (RDE) technique, respectively. For PtCo/C catalysts modified with 0.4 and 3.2 wt% of Mn, the Pt/Co atomic ratio is 3.5 and the size is about 3.0 nm with the same face centered cubic (fcc) structure. Moreover, Mn-modified PtCo/C catalysts have the same surface composition, which is about Pt/Co/Mn of 62/32/6, and their ORR activity are both higher than that of PtCo/C and commercial Pt/C catalysts. After accelerated durability test (ADT) of 1700 cycles, Mn-2 with 3.2 wt% Mn addition still presents the best ORR mass activity, which is about 420% of commercial Pt/C. In the Mn-modified PtCo/C system, due to the existence of the neighboring Co and/or Mn oxide, there is OH repulsion between Pt-OH and these non-noble metal hydroxides or oxides, decreasing the OH coverage on Pt and increasing the number of free Pt active sites. Besides, based on the XAS analysis, the unfilled d-orbital values and extent of hybridization of Pt and Co/Mn of the PtCo and Mn-modified samples are very similar. Therefore, the promotional effect on ORR performance of Mn-2 is attributed to the most enhanced Pt-skin structure, highest Pt usage, and comparable electron transfer number during ORR instead of changes in d-orbital vacancy and alloying degree.
AB - The effect of Mn addition on the promotion of oxygen reduction reaction (ORR) performance for PtCo/C catalysts is investigated. The structures, surface compositions, chemical compositions, local structural parameters including coordination numbers and bond distances, morphologies and electrochemical properties of prepared catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectrometer (ICP-AES), extended X-ray absorption fine structure (EXAFS), high resolution transmission electron microscopy (HRTEM) and rotating disk electrode (RDE) technique, respectively. For PtCo/C catalysts modified with 0.4 and 3.2 wt% of Mn, the Pt/Co atomic ratio is 3.5 and the size is about 3.0 nm with the same face centered cubic (fcc) structure. Moreover, Mn-modified PtCo/C catalysts have the same surface composition, which is about Pt/Co/Mn of 62/32/6, and their ORR activity are both higher than that of PtCo/C and commercial Pt/C catalysts. After accelerated durability test (ADT) of 1700 cycles, Mn-2 with 3.2 wt% Mn addition still presents the best ORR mass activity, which is about 420% of commercial Pt/C. In the Mn-modified PtCo/C system, due to the existence of the neighboring Co and/or Mn oxide, there is OH repulsion between Pt-OH and these non-noble metal hydroxides or oxides, decreasing the OH coverage on Pt and increasing the number of free Pt active sites. Besides, based on the XAS analysis, the unfilled d-orbital values and extent of hybridization of Pt and Co/Mn of the PtCo and Mn-modified samples are very similar. Therefore, the promotional effect on ORR performance of Mn-2 is attributed to the most enhanced Pt-skin structure, highest Pt usage, and comparable electron transfer number during ORR instead of changes in d-orbital vacancy and alloying degree.
KW - (EXAFS)
KW - Electron transfer number
KW - Extended X-ray absorption fine structure
KW - Mn
KW - Oxygen reduction reaction (ORR)
KW - PtCo/C catalysts
UR - http://www.scopus.com/inward/record.url?scp=84878325399&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2013.04.138
DO - 10.1016/j.electacta.2013.04.138
M3 - 期刊論文
AN - SCOPUS:84878325399
SN - 0013-4686
VL - 105
SP - 180
EP - 187
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -