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Atomically dispersed metal catalysts have demonstrated superb electrocatalytic activity because of optimal atom efficiency. However, a rational design of low-cost, high-performance single atom catalysts remains a great challenge due to the elusive chemical reactions of the formation of metal active sites. In this work, biomass hydrogel is prepared as a template for mass production of three-dimensional carbon aerogel-supported single metal atom catalysts. By tailoring the structure of the hydrogel templates, the obtained carbon aerogels exhibit an increase of microporous defects which capture and stabilize isolated metal atoms and minimize aggregation during pyrolysis. Extended X-ray absorption fine structure, Mössbauer spectroscopy, and nitrogen adsorption–desorption isotherm measurements indicate that single metal centers of FeN 4 are formed and embedded within the hierarchical porous carbon frameworks. The obtained composites exhibit outstanding catalytic activity towards oxygen reduction in alkaline media, with a high onset potential of +1.05 V and half-wave potential of +0.88 V, as well as excellent durability. Remarkably, when the carbon aerogels are used as the cathode catalyst in an aluminum–air battery, the battery achieves an ultrahigh open-circuit voltage of 1.81 V, large power density of 181.1 mW cm −2 and stable discharge voltage of 1.70 V at 20 mA cm −2 , markedly better than those with commercial Pt/C as the cathode catalyst.
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Carbon‐Supported Single Atom Catalysts for Electrochemical Energy Conversion and Storage
Abstract Single atoms of select transition metals supported on carbon substrates have emerged as a unique system for electrocatalysis because of maximal atom utilization (≈100%) and high efficiency for a range of reactions involved in electrochemical energy conversion and storage, such as the oxygen reduction, oxygen evolution, hydrogen evolution, and CO2reduction reactions. Herein, the leading strategies for the preparation of single atom catalysts are summarized, and the electrocatalytic performance of the resulting samples for the various reactions is discussed. In general, the carbon substrate not only provides a stabilizing matrix for the metal atoms, but also impacts the electronic density of the metal atoms due to strong interfacial interactions, which may lead to the formation of additional active sites by the adjacent carbon atoms and hence enhanced electrocatalytic activity. This necessitates a detailed understanding of the material structures at the atomic level, a critical step in the construction of a relevant structural model for theoretical simulations and calculations. Finally, a perspective is included highlighting the promises and challenges for the future development of carbon‐supported single atom catalysts in electrocatalysis.
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- Award ID(s):
- 1710408
- PAR ID:
- 10072764
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 30
- Issue:
- 48
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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