April 7 - 11, 2025
Seattle, Washington
Symposium Supporters
2025 MRS Spring Meeting & Exhibit
SU05.05.20
(ORR) kinetics at the cathode side, which demands highly efficient and durable catalysts for generating adequate rates. By keeping
this in view, herein, we report a systematic study to unveil the effect of structure configuration on the ORR activity of tri-metallic
nanocatalysts (NC)s comprising atomic iridium (Ir) cluster (0.5 wt % of Ir)-anchored Pd nanoparticles (NP)s on the tetrahedral
symmetric Ni-oxide support (denoted as NPI), prepared via a temperature-controlled wet chemical reduction method. For the
optimum condition when the impregnation temperature for Ni-crystal growth is 40 °C, the Ir-cluster-decorated Ni@Pd nanoislands
are formed (hereafter denoted as NPI-40), outperforming the commercial Johnson Matthey-Pt/C (J.M.-Pt/C; 20 wt % Pt) catalyst
by 181-fold with an unprecedented high mass activity of 12,163 mAmgIr−1 at 0.85 V vs RHE in alkaline ORR (0.1 M KOH). More
importantly, NPI-40 NC retained 100% ORR performance with no degradation up to 20,000 accelerated degradation test (ADT)
cycles, while only a 5 mV loss in half-wave potential (E1/2) is observed after 30 k ADT cycles. Besides, Ir-cluster-decorated Nicore@
unconformable Pdshell and Ni-to-Pd epitaxial structures are formed at 25 °C (NPI-RT) and 70 °C (NPI-70) impregnation
temperatures, respectively, showing the significantly decreased mass activities of 997 and 5146 mAmgIr−1 at 0.85 V vs RHE. The
results of physical structure inspections and electrochemical analysis suggest that such an exceptional ORR performance of NPI-40
NC originates from the potential synergism between the high density of the occupied Ir-d orbital and the adjacent compressively
strained Ni−Pd interface, where Ir sites offer optimal adsorption energy for O2 splitting and the Ni−Pd interface facilitates the
subsequent desorption of hydroxide ions (OH−). We believe that the obtained results will open new avenues for the facile design of Pt-free NCs for fuel cell cathodes and will benefit fuel-cell technology via both ecologically and economically friendly means.
Enhancement of Oxygen Reduction Reaction Performance by Iridium-Cluster-Decorated Ni@Pd Nanocatalysts
When and Where
Apr 9, 2025
5:00pm - 7:00pm
5:00pm - 7:00pm
Summit, Level 2, Flex Hall C
Presenter(s)
Co-Author(s)
Pochun Chen1,Wei-Tze Sun1,Tsan-Yao Chen2
National Taipei University of Technology1,National Tsing Hua University2
Abstract
Pochun Chen1,Wei-Tze Sun1,Tsan-Yao Chen2
National Taipei University of Technology1,National Tsing Hua University2
The widespread market introduction of fuel cells is severely restricted by the sluggish oxygen reduction reaction(ORR) kinetics at the cathode side, which demands highly efficient and durable catalysts for generating adequate rates. By keeping
this in view, herein, we report a systematic study to unveil the effect of structure configuration on the ORR activity of tri-metallic
nanocatalysts (NC)s comprising atomic iridium (Ir) cluster (0.5 wt % of Ir)-anchored Pd nanoparticles (NP)s on the tetrahedral
symmetric Ni-oxide support (denoted as NPI), prepared via a temperature-controlled wet chemical reduction method. For the
optimum condition when the impregnation temperature for Ni-crystal growth is 40 °C, the Ir-cluster-decorated Ni@Pd nanoislands
are formed (hereafter denoted as NPI-40), outperforming the commercial Johnson Matthey-Pt/C (J.M.-Pt/C; 20 wt % Pt) catalyst
by 181-fold with an unprecedented high mass activity of 12,163 mAmgIr−1 at 0.85 V vs RHE in alkaline ORR (0.1 M KOH). More
importantly, NPI-40 NC retained 100% ORR performance with no degradation up to 20,000 accelerated degradation test (ADT)
cycles, while only a 5 mV loss in half-wave potential (E1/2) is observed after 30 k ADT cycles. Besides, Ir-cluster-decorated Nicore@
unconformable Pdshell and Ni-to-Pd epitaxial structures are formed at 25 °C (NPI-RT) and 70 °C (NPI-70) impregnation
temperatures, respectively, showing the significantly decreased mass activities of 997 and 5146 mAmgIr−1 at 0.85 V vs RHE. The
results of physical structure inspections and electrochemical analysis suggest that such an exceptional ORR performance of NPI-40
NC originates from the potential synergism between the high density of the occupied Ir-d orbital and the adjacent compressively
strained Ni−Pd interface, where Ir sites offer optimal adsorption energy for O2 splitting and the Ni−Pd interface facilitates the
subsequent desorption of hydroxide ions (OH−). We believe that the obtained results will open new avenues for the facile design of Pt-free NCs for fuel cell cathodes and will benefit fuel-cell technology via both ecologically and economically friendly means.
Keywords
Ir
Symposium Organizers
Chong Liu, The University of Chicago
Sui Zhang, National University of Singapore
Karen Mulfort, Argonne National Laboratory
Ying Li, University of Wisconsin--Madison
Session Chairs
Ying Li
Chong Liu
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