The local coordination environment around catalytically active sites plays a vital role in tuning the activity of electrocatalysts made of carbon-supported metal nanoparticles. However, the rational design of electrocatalysts with improved performance by controlling this environment is hampered by synthetic limitations and insufficient mechanistic understanding of how the catalytic phase forms. Here we show that introducing F atoms into Pd/N–C catalysts modifies the environment around the Pd and improves both activity and durability for the ethanol oxidation reaction and the oxygen reduction reaction. Our data suggest that F atom introduction creates a more N-rich Pd surface, which is favourable for catalysis. Durability is enhanced by inhibition of Pd migration and decreased carbon corrosion. A direct ethanol fuel cell that uses the Pd/N–C catalyst with F atoms introduced for both the ethanol oxidation reaction and oxygen reduction reaction achieves a maximum power density of 0.57 W cm−2 and more than 5,900 hours of operation. Pd/C catalysts containing other heteroatoms (P, S, B) can also be improved through the addition of F atoms.
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This work was supported by a start-up grant from the University of Central Florida. J.C. acknowledges financial support from the Preeminent Postdoctoral Program (P3) at the University of Central Florida. The XPS test was supported by the US National Science Foundation (Division of Electrical, Communications and Cyber Systems, no. 1726636), hosted in the Materials Characterization Facility and Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, College of Engineering and Computer Science, University of Central Florida. Z.F. acknowledges support from the US National Science Foundation (National Nanotechnology Coordinated Infrastructure, no. 2025489). Guofeng Wang and B.L. acknowledge support from the US National Science Foundation (Division of Chemical, Bioengineering, Environmental and Transport Systems, no. 1804534). Computational resources were provided by the University of Pittsburgh Center for Research Computing as well as the Extreme Science and Engineering Discovery Environment, which is supported by National Science Foundation grant no. ACI-1053575. The use of the Advanced Photon Source at Argonne National Laboratory for XAS measurements at beamlines 5-BM and 12-BM was supported by the US Department of Energy under contract no. DE-AC02-06CH11357. DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) is supported through E. I. duPont de Nemours and Company, Northwestern University and the Dow Chemical Company. M.G. acknowledges support from the Guangdong Innovative and Entrepreneurial Research Team Program (grant no. 2019ZT08C044) and the Peacook Team Program supported by the Science, Technology and Innovation Commission of Shenzhen Municipality (KQTD20190929173815000).
The fluorinated fuel cell catalysts disclosed in this work have been filed as US Provisional Patent Application (Serial No. 63/260,768) with Y.Y. and J.C. as inventors. The status of the patent application is pending.
Peer review information Nature Energy thanks Wenzhen Li and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Chang, J., Wang, G., Wang, M. et al. Improving Pd–N–C fuel cell electrocatalysts through fluorination-driven rearrangements of local coordination environment. Nat Energy 6, 1144–1153 (2021). https://doi.org/10.1038/s41560-021-00940-4
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