A kind of pollution known as electromagnetic interference (EMI), which results from ubiquitous usage of various electronic communication and military radar equipment, has been receiving increasing attention recently. However, large-area EMI shielding on transparent and/or curved surfaces, including building windows, curved glass wall, and special requirements spaces (SRSs), remains hard to achieve. In this paper, a silver nanofiber (AgNF) based flexible and transparent EMI shielding film was successfully assembled via a room-temperature roll-to-roll production method. For transparent application scenario, AgNF with 89% transmittance in visible range and 1 μm thickness shows~20 dB shielding efficiency (EMI SE). On the other hand, total shielding (>50 dB) is obtained when the thickness of AgNF increases to 10 μm, while its transmittance in visible range remains higher than 75%. Considering the facile and scale-free production technology, this material can be readily applied in large-scale, transparent, and/or SRSs EMI shielding.
The representative spinel-type materials AB2O4 (both A and B are transition metals) electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been investigated and significant improvements have been achieved in the activity and durability for ORR and OER in the alkaline solution. But CoFeCoO4 was not explored widely like ZnCo2O4 (or NiCo2O[Formula: see text] as the ORR electrocatalyst for its relatively complicated atomic site occupation. CoFeCoO4 has a typical cubic spinel structure with Co[Formula: see text] in the tetrahedron and Co[Formula: see text] and Fe[Formula: see text] in the octahedron. A mixture of Co[Formula: see text] and Fe[Formula: see text] in the B site makes the oxide have a wider overlap between transition metal 3d orbit and O 2p orbit, which can lead to an effective charge transfer in the rate-determining steps of ORR process and then enhance the ORR activity. The high electronic conductivity and specific surface area of rGO can accelerate charger transfer and provide more catalytic sites, which would contribute to a faster ORR process. In this work, the porous spindle CoFeCoO4 microparticles which were synthesized by hydrothermal technology, were assembled on the rGO surface to obtain the CoFeCoO4/rGO composite, which exhibited enhanced ORR activity and catalytic stability comparable to that of Pt/C. On the other hand, the OER catalytic activity of the prepared samples was also studied to explore the potential of CoFeCoO4/rGO as a bifunctional oxygen catalyst.
The novel composite structure of TiN nanoparticles enclosed by graphite carbon coating (TiN/C) has been successfully prepared through a facile one-step solid state method under N 2 atmosphere using the TiO 2 powder and melamine as raw materials. TiN nanoparticles with size ranging from 12 to 15 nm are covered by filmy graphite carbon layer, and their electrocatalytic properties towards oxygen reduction are further investigated. Benefiting from the surface chemical bonding of oxide and oxynitride components, TiN/C nanocomposite exhibit a considerable catalytic activity. The current density of TiN/C nanocomposite (4.65 mA cm −2 at 0.2 V) is comparable to that of commercial Pt/C catalyst, in spite of a little more negative gap in onset potential. Moreover, the TiN/C nanocomposite has excellent long time durability and methanol tolerant performance with the protection of graphite carbon coating.
Ultrathin porous spinel structure ZnCo 2 O 4 nanosheets (ZCONSs) are successfully prepared by a facile combination of hexamethylenetetramine-assisted mild water bath reaction and a heat treatment process. The ultrathin film shape and porous of the as-prepared ZCONSs were demonstrated by a transmission electron microscope. Such a specific nanostructure of the as-prepared ZCONS provided an efficient charge transfer process, as well as an efficient mass transport process. Therefore, in the oxygen reduction reaction (ORR) test, ZCONS shows good electrocatalytic ability. Additionally, because of the ultrathin nanosheets possess enough extra free space for alleviating, so that endow long-term cycling stability, make the catalyst possesses superior durability and excellent methanol tolerance ability.
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