期刊
SUSTAINABLE ENERGY & FUELS
卷 3, 期 7, 页码 1668-1681出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c9se00074g
关键词
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资金
- National Tsing Hua University, Taiwan [N103K30211, 103N1200K3]
- Ministry of Science and Technology, Taiwan [MOST 106-2112-M-007-016-MY3, MOST 105-3113-E-006-019-CC2]
- Hierarchical Green-Energy Materials (Hi-GEM) Research Center, from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE)
- Ministry of Science and Technology in Taiwan [MOST 107-3017-F-006-003]
Surface tailoring as well as inner structure design at the atomic scale are of primary importance for the activity and durability of nanocatalysts (NCs) in electrochemical applications. In this study, a novel structural candidate containing a Cu core and Pt cluster decorated Pd shell with a balance struck between the performance and cost considerations for the oxygen reduction reaction (ORR) is proposed. The carbon nanotube supported NCs are synthesized using a wet chemical reduction method with different ratios of Pt from 5 to 14 wt%. Our results demonstrate a robust assessment for programming the ORR performance by Pt loading control in the NCs. For the optimum case (similar to 5.0 wt% of Pt), the mass activity (M.A.) is similar to 639 mA mg(Pt)(-1). This value is improved by 9-folds compared to that of commercial Pt NC (J.M.-Pt/C) at 0.85 V vs. RHE and can be attributed to the formation of a high density of surface truncations in the NC surface. When the Pt loading is similar to 9 wt%, the NC forms multi-faceted twin particles with low surface defects and thus has the highest stability (+/-0.5% of current vibration) in an accelerated degradation test (ADT) among the experimental samples. Further increasing Pt to 14 wt%, restructures the NC into a local ordered crystal with certain amounts of Pt island clusters in the surface. Such a phenomenon results in a vibration of the current density by surface restructure upon oxidation and reduction of Pt oxides in a ADT test and possesses a residual current density of 92% compared to its original value after 40 k cycles. Most importantly, our observations bring fundamental and practical insights into the role of surface defects in electrocatalysis and present a new strategy to surmount a dilemma between the reliability and activity of ORR NCs.
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