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ABSTRACT Metal/carbon‐based nanocomposites have attracted significant interest for electrochemical water splitting due to their unique interfacial electronic structures, abundant active sites, and catalytic bifunctionality toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, Co/CoO‐rGO composites consisting of Co/CoO heterostructured nanoparticles encapsulated within a graphitized carbon scaffold are produced via magnetic induction heating at controlled currents for 10 s with cobalt(II) nitrate and reduced graphene oxide (rGO) loaded on nickel foam and effectively catalyze both HER and OER in alkaline media. Among the series, the sample prepared at 400 A for 10 s exhibits the best performance, featuring an overpotential of −144 mV for HER and +390 mV for OER at 10 mA cm−2and 50 mA cm−2, respectively. The bifunctional activity can then be exploited for full water splitting, where a low cell voltage of 1.61 V is needed to generate a current density of 10 mA cm−2, 260 mV better than that with commercial Pt/C and RuO2. The remarkable performance is attributed to the synergistic interaction between the Co and CoO domains, enhanced charge transfer at the heterojunction interface, and conductive carbon support. These results highlight the potential of Co/CoO‐based nanocomposites as efficient and low‐cost catalysts for overall water splitting and the scalability of the MIH technology.
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NiFe Nanoparticle Nest Supported on Graphene as Electrocatalyst for Highly Efficient Oxygen Evolution Reaction
Abstract Designing cost‐efffective electrocatalysts for the oxygen evolution reaction (OER) holds significant importance in the progression of clean energy generation and efficient energy storage technologies, such as water splitting and rechargeable metal–air batteries. In this work, an OER electrocatalyst is developed using Ni and Fe precursors in combination with different proportions of graphene oxide. The catalyst synthesis involved a rapid reduction process, facilitated by adding sodium borohydride, which successfully formed NiFe nanoparticle nests on graphene support (NiFe NNG). The incorporation of graphene support enhances the catalytic activity, electron transferability, and electrical conductivity of the NiFe‐based catalyst. The NiFe NNG catalyst exhibits outstanding performance, characterized by a low overpotential of 292.3 mV and a Tafel slope of 48 mV dec−1, achieved at a current density of 10 mA cm−2. Moreover, the catalyst exhibits remarkable stability over extended durations. The OER performance of NiFe NNG is on par with that of commercial IrO2in alkaline media. Such superb OER catalytic performance can be attributed to the synergistic effect between the NiFe nanoparticle nests and graphene, which arises from their large surface area and outstanding intrinsic catalytic activity. The excellent electrochemical properties of NiFe NNG hold great promise for further applications in energy storage and conversion devices.
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- PAR ID:
- 10488177
- Publisher / Repository:
- Small
- Date Published:
- Journal Name:
- Small
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Journal Article:
- https://doi.org/10.1002/smll.202308278
