Designing and developing high-efficient and durable non-precious-metal oxygen evolution reaction (OER) electrocatalysts is relevant for hydrogen generation from seawater splitting. Herein, a novel ...interfacial-coupled Fe-BDC/CoWO4/NF nanosheet array has been demonstrated via a two-step solvothermal method, which can effectively accelerate OER with an ultra-low overpotential of 254 mV at 100 mA cm−2 in 1.0 M KOH. More interestingly, it exhibits overpotentials of 290, 296, and 301 mV at 100 mA cm−2, when using 1.0 M KOH with 0.5, 1.0, and 2.0 M NaCl as simulated seawater and a lifetime of more than 250 h. The excellent performance for OER is benefit from the distinctive interfacial-structure, optimizing the OER process energy barrier of and lowering the adsorption energy of oxygen-containing intermediates, effectively speeding up the OER kinetics. This work opens a new strategy for designing versatile base metal OER electrocatalysts.
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•Interface-coupled Fe-BDC/CoWO4/NF nanosheets arrays were successfully synthesized.•The catalyst has excellent OER activity and good corrosion resistance to Cl− in simulated seawater.•This work opens a new strategy for designing versatile base metal OER electrocatalysts.
Abstract Seawater electrolysis is a sustainable technology for producing hydrogen that would neither cause global freshwater shortages nor create carbon emissions. However, this technology is ...severely hampered by the insufficient stability and the competition from the chlorine evolution reaction (ClER) in actual application. Herein, a metal–organic framework (MOF)‐on‐MOF heterojunction (Ni‐BDC/NH 2 ‐MIL‐88B(Fe)) denoted as (Ni‐BDC/NM88B(Fe)) is synthesized as an effective oxygen evolution reaction (OER) electrocatalyst for high‐performance seawater electrolysis, which exhibits a long stability of 200 h and low overpotentials of 232 and 299 mV at 100 mA cm −2 in alkaline freshwater and seawater solution, respectively. The exceptional performance is attributed to the rapid self‐reconstruction of Ni‐BDC/NM88B(Fe) to produce NiFeOOH protective layer, thereby avoiding ClER‐induced dissolution. Moreover, the interface interaction between Ni‐BDC and NM88B(Fe) could form the Ni─O─Fe bonds in Ni‐BDC/NM88B(Fe) to promote the electron transfer and lower the energy barrier of the rate‐determining step, thereby accelerating the OER. These electrochemical properties make it intriguing candidate as an efficient electrocatalyst for practical alkaline seawater electrolysis.
The (Fe,Ni)OOH-NiSe2 electrocatalyst with dual active sites was obtained by designing the FeOOH-NiSe2 pre-electrocatalyst via an electrochemical self-activation strategy. The electronic structure and ...d-band center of the metal sites are effectively regulated by the unique interface between (Fe,Ni)OOH and NiSe2, which is bound by M(Fe,Ni)-O-Se. This lowers the energy barrier of the rate-determining step (RDS) in the OER reaction processes, speeding up the kinetics of oxygen evolution reaction.
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•Low-cost catalyst, (Fe,Ni)OOH-NiSe2 heterostructure, was obtained by an in-situ electrochemical activation strategy.•Fe/Ni dual sites have been mediated by combined O/Se anions due to the unique interface.•(Fe,Ni)OOH-NiSe2 heterostructure possessed superior OER activity and stability.
Metal oxyhydroxides produced by the surface reconstruction were widely considered as active catalytic species in the oxygen evolution reaction (OER). However, simultaneous activation of metal sites in surface oxyhydroxides remains a great challenge. In this study, the interface self-activation strategy was utilized to simultaneously activate both the iron and nickel sites at the surface oxyhydroxides of (Fe,Ni)OOH-NiSe2 nano heterostructure. The OER activity was greatly boosted by the dual activation of active sites, resulting in an overpotential of 245 mV@100 mA cm−2 with a small Tafel slope of 44 mV dec−1. The finely constructed FeOOH-NiSe2 heterostructure was transformed into (Fe,Ni)OOH-NiSe2 through the formation of distinct bonds of M(Fe,Ni)-O-Se during the OER process, which was discovered through a combination of experimental studies with DFT calculations. A fast OER reaction dynamic was achieved due to the unique self-optimized interface structure which produced a dual synergistic effect between the interface structure and the active sites of Fe and Ni of oxyhydroxides, modulated the electronic structure and d band center of active sites, and increased the number of optimum active sites. This work paves a way to design high-performance electrocatalysts with multiple active sites for other electrochemical reactions.
•A simple and fast microwave-assisted strategy of synthesizing Ni3S2/NiCo2S4 nanosheets.•Numerous ultra-thin Ni3S2 nanosheets were produced on the surface of NiCo2S4 due tounequal ion diffusion.•The ...Ni3S2/NiCo2S4-15 electrode attained an ultra-high specific capacitance of 3299 F/g at 13.3 A/g.
The advanced structural design of supercapacitor (SC) electrodes is an effective approach to enhance their performance towards energy conversion and storage. Herein, ultrathin NiCo2S4 nanosheets on Ni foam (NF) with uniform Ni3S2 nanocrystals were synthesised via a simple microwave-assisted sulfidation process. The cooperation of massive ultrathin Ni3S2 nanocrystals and cross-linking NiCo2S4 nanosheets endowed the Ni3S2/NiCo2S4/NF electrodes with a high specific capacitance of 3299 F/g at 13.3 A/g (11.5 F/cm2 at 5 mA/cm2), a remarkable rate capacity of 77% retention at 20 A/g, and cycling performance of 61% retention after 8000 cycles at 50 mA/cm2. This work illustrates that the Ni3S2/NiCo2S4/NF electrodes synthesised via a simple microwave-assisted method are promising anode materials in asymmetric SCs.
Seawater electrolysis is a sustainable technology for producing hydrogen that would neither cause global freshwater shortages nor create carbon emissions. However, this technology is severely ...hampered by the insufficient stability and the competition from the chlorine evolution reaction (ClER) in actual application. Herein, a metal–organic framework (MOF)‐on‐MOF heterojunction (Ni‐BDC/NH2‐MIL‐88B(Fe)) denoted as (Ni‐BDC/NM88B(Fe)) is synthesized as an effective oxygen evolution reaction (OER) electrocatalyst for high‐performance seawater electrolysis, which exhibits a long stability of 200 h and low overpotentials of 232 and 299 mV at 100 mA cm−2 in alkaline freshwater and seawater solution, respectively. The exceptional performance is attributed to the rapid self‐reconstruction of Ni‐BDC/NM88B(Fe) to produce NiFeOOH protective layer, thereby avoiding ClER‐induced dissolution. Moreover, the interface interaction between Ni‐BDC and NM88B(Fe) could form the Ni─O─Fe bonds in Ni‐BDC/NM88B(Fe) to promote the electron transfer and lower the energy barrier of the rate‐determining step, thereby accelerating the OER. These electrochemical properties make it intriguing candidate as an efficient electrocatalyst for practical alkaline seawater electrolysis.
A hetero‐structured Ni‐BDC/NM88B(Fe) metal–organic framework is synthesized to be as an outstanding electrocatalyst for seawater oxidation. The unique electronic channel (Ni─O─Fe) in this heterostructure not only enables the rapid reconstruction to generate the protective layer of NiFeOOH, thereby avoiding the effects of CER, but also optimizes the adsorption energy of the intermediates, leading to superior seawater oxidation performance.
Facile and controllable synthesis of efficient and stable nonprecious electrocatalysts for the oxygen evolution reaction (OER) is crucial for prospective sustainable energy conversion and storage ...technologies. Iron-doped nickel sulfide nanosheet electrodes were synthesized through simple in situ sulfidation of nickel foil with ferrous chloride, which resulted in the formation of ultrathin Fe-doped Ni3S2 nanosheets on the Ni foam (NF) substrate (Fe x -Ni3S2/NF). The developed Fe1-Ni2S3/NF electrocatalyst shows superb catalytic activity during the oxygen evolution reaction, owing to its high intrinsic activity, abundant active sites, and a superior transfer coefficient, requiring low overpotentials of only 244 and 306 mV at 100 mA cm–2 for the OER in 1.0 M KOH and 1.0 M KOH + 0.5 M NaCl solutions. This catalyst can maintain stable electrolysis in alkaline seawater for more than 100 h. The excellent activity and stability of this catalyst proved it to be an economical alternative to commercial noble metal-based catalysts in renewable energy-related technologies.
In electrochemical energy storage and conversion systems, urea oxidation reaction (UOR) can produce hydrogen and mitigate pollution from urea-rich wastewater in a low-energy manner, whereas the ...development of this technique was limited via a lack of economical and cost-effective UOR catalysts. Herein, a unique electrocatalyst of MoO3/Ni-N-C was synthesized from a Mo element-incorporated Ni-MOF by heating under an inert atmosphere. The prepared MoO3/Ni-N-C electrode shows superior activity toward UOR, which only needs a low potential of 1.42 V (vs RHE) at 50 mA cm–2 in 1.0 M KOH with 0.5 M urea. The excellent performance for UOR is attributed to the synergistic effect between molybdenum and nickel, the modulation of the electronic structure for the nickel site by MoO3, accelerating the charge transfer, and tuning the reaction interface adsorption energy to enhance electrocatalytic activity. This work provides strategies and directions for exploring other advanced UOR electrode material designs.
Owing to the increasing power density of miniaturized and high‐frequency electronic devices, flexible thermal interface materials (TIMs) with the electromagnetic interference (EMI) shielding property ...are in urgent demand to maintain the system performance and reliability. Recently, carbon‐based TIMs receive considerable attention due to the ultrahigh intrinsic thermal conductivity (TC). However, the large‐scale production of such TIMs is restricted by some technical difficulties, such as production‐induced defects of graphite sheets, poor microstructure architecture within the matrix, and nonnegligible interfacial thermal resistance result from the strong phono scattering. In this work, inspired by the structure and production process of millefeuille cakes, a unique double self‐assembly strategy for fabricating ultrahigh thermal conductive TIMs with superior EMI shielding performance is demonstrated. The percolating and oriented multilayered microstructure enables the TIM to exhibit an ultrahigh in‐plane TC of 233.67 W m−1 K−1 together with an outstanding EMI shielding effectiveness of 79.0 dB (at 12.4 GHz). In the TIM evaluation system, a nearly 45 °C decrease is obtained by this TIM when compared to the commercial material. The obtained TIM achieves the desired balance between thermal conduction and EMI shielding performance, indicating broad prospects in the fields of military applications and next‐generation thermal management systems.
Herein, a multifunctional thermal interface material is fabricated through the double self‐assembly technique to fulfil advanced thermal management applications concerning electromagnetic interference (EMI). According to the building of oriented multilayered microstructure and interfacial enhancement via nano‐coating, the composite maintains optimized coordination of the EMI shielding (shielding efficiency over 99.9999%) and thermal conductivity (in‐plane TC of 233.67 W m−1 K−1).
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