TY - JOUR
T1 - Composition effect of oxygen reduction reaction on PtSn nanorods
T2 - An experimental and computational study
AU - Yan, Shao Yan
AU - Liu, Chen Wei
AU - Huang, Tzu Hsi
AU - Guo, Yao Zhang
AU - Lee, Sheng Wei
AU - Wang, Jeng Han
AU - Wang, Kuan Wen
N1 - Funding Information:
This work is supported by the Ministry of Science and Technology , R.O.C. ( MOST 104-2628-E-008-005-MY3 and 106-2113-M-003-003 ). CPU time at Taiwan's National Center for High-performance Computing (NCHC) is greatly appreciated.
Publisher Copyright:
© 2018 Hydrogen Energy Publications LLC
PY - 2018/8/2
Y1 - 2018/8/2
N2 - In the development of emerging energy, proton exchange membrane fuel cells (PEMFCs) have been widely researched. Nevertheless, because of the high price and scarcity of Pt and its sluggish kinetics for oxygen reduction reaction (ORR), the preparation of highly effective cathode catalysts becomes one of the main challenges for PEMFCs in the practical application. In this study, carbon supported PtSn nanorods (NRs) with metal loading of 50 wt % and different Pt/Sn ratios of 80/20, 65/35 and 50/50 have been prepared by formic acid reduction method. The ORR performance of the catalysts can be promoted synergistically by one-dimensional (1-D) NRs and is varied with the Pt/Sn ratios. The experimental and computational efforts reveal that the Sn addition can lower the unoccupied d-band of neighboring Pt and the oxygen-containing species (OCS) on Sn can suppress their oxidation through the repulsion effect. Consequently, PtSn electrodes show the improved ORR activity; Pt50Sn50 with the highest Sn content results in the highest mass activity. On the other hand, the negatively charged OCS on Sn attracts the positively charged Pt and destructs the structures of PtSn NRs. Accordingly, Pt80Sn20 with the lowest Sn contain has the highest concentration of 1-D PtSn NRs and shows the best stability in the accelerated durability test (ADT). Our results clarify the mechanism of ORR on PtSn electrodes and suggest the importance of the precise control of atomic ratios on PtSn catalysts for the practical purpose. The findings open new perspectives about the origins of the activity and stability of the PtSn catalysts, especially for 1-D catalysts.
AB - In the development of emerging energy, proton exchange membrane fuel cells (PEMFCs) have been widely researched. Nevertheless, because of the high price and scarcity of Pt and its sluggish kinetics for oxygen reduction reaction (ORR), the preparation of highly effective cathode catalysts becomes one of the main challenges for PEMFCs in the practical application. In this study, carbon supported PtSn nanorods (NRs) with metal loading of 50 wt % and different Pt/Sn ratios of 80/20, 65/35 and 50/50 have been prepared by formic acid reduction method. The ORR performance of the catalysts can be promoted synergistically by one-dimensional (1-D) NRs and is varied with the Pt/Sn ratios. The experimental and computational efforts reveal that the Sn addition can lower the unoccupied d-band of neighboring Pt and the oxygen-containing species (OCS) on Sn can suppress their oxidation through the repulsion effect. Consequently, PtSn electrodes show the improved ORR activity; Pt50Sn50 with the highest Sn content results in the highest mass activity. On the other hand, the negatively charged OCS on Sn attracts the positively charged Pt and destructs the structures of PtSn NRs. Accordingly, Pt80Sn20 with the lowest Sn contain has the highest concentration of 1-D PtSn NRs and shows the best stability in the accelerated durability test (ADT). Our results clarify the mechanism of ORR on PtSn electrodes and suggest the importance of the precise control of atomic ratios on PtSn catalysts for the practical purpose. The findings open new perspectives about the origins of the activity and stability of the PtSn catalysts, especially for 1-D catalysts.
KW - Number of unoccupied d-states (H)
KW - One-dimensional (1-D) structure
KW - Oxygen reduction reaction (ORR)
KW - Pt/Sn ratio
KW - Repulsion effect
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U2 - 10.1016/j.ijhydene.2018.05.176
DO - 10.1016/j.ijhydene.2018.05.176
M3 - Article
AN - SCOPUS:85049307650
SN - 0360-3199
VL - 43
SP - 14427
EP - 14438
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 31
ER -