Carbon nanocomposites based on transition-metal oxides have been attracting extensive attention as cost-effective catalysts towards the oxygen reduction reaction (ORR). However, the activity remains subpar as compared to state-of-the-art platinum catalysts. One way to enhance the ORR performance is to dope a second metal into the nanocomposite to manipulate the electronic structure and hence the interactions with key reaction intermediates. Herein, dual metal (Ru and Fe) and nitrogen codoped carbon (RuFe-NC) nanocomposites were synthesized by controlled pyrolysis of a Fe–Ru–Fe trinuclear complex along with zeolitic imidazolate framework-8. The obtained porous nanocomposites consisted of Ru-doped Fe 2 O 3 nanoparticles embedded within a carbon scaffold, and exhibited an ORR activity in alkaline media rivaling that of commercial Pt/C, which was also markedly better than those of the monometallic counterparts and nanocomposites prepared with a simple mixture of the individual monometallic compound precursors. Structural characterization suggests that the use of the trinuclear complex facilitated the atomic dispersion of ruthenium within the iron oxide nanoparticles and charge transfer between the metal centers led to a high ORR activity. Results from this study suggest that rational design of heteronuclear complexes may be a unique strategy in the structural engineering of carbon-metal nanocomposites for high-performance electrocatalysis.
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Nanoscale Design of Pd‐Based Electrocatalysts for Oxygen Reduction Reaction Enhancement in Alkaline Media
Palladium (Pd)‐based electrocatalysts have recently emerged as one class of the foremost promising candidates for the oxygen reduction reaction (ORR) in alkaline media due to their excellent ORR activity and durability and lower costs compared with platinum. Insightful design of Pd‐based nano‐architectures with optimized active surface sites and maximal intrinsic performance is central to promoting the ORR applications. To further accelerate the sluggish ORR kinetics at the cathode of fuel cells and substantially decrease the overall cost of the electrocatalysts, various strategies, including controlled sizes and shapes with selected crystallographic facets, crystal‐phase engineering, heteroatom doping, tailored surface strains, and surface engineering by de‐alloying, have been extensively developed in the past decade. In this review, a brief introduction to the fundamental ORR mechanisms of Pd‐based electrocatalysts in alkaline media is presented, followed by a thorough discussion on various strategies for delicately designing high‐performance Pd‐based catalysts with corresponding examples. Thereafter, the perspectives and new insights into the challenges are outlined, and some emerging research directions related to the rational design and controlled synthesis of Pd‐based ORR electrocatalysts are also proposed.
- Award ID(s):
- 1808383
- NSF-PAR ID:
- 10362292
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small Structures
- Volume:
- 3
- Issue:
- 2
- ISSN:
- 2688-4062
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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