Hydrophobic sponge structure‐based triboelectric nanogenerators using an inverse opal structured film for sustainable energy harvesting over a wide range of humid atmosphere have been successfully ...demonstrated. The output voltage and current density reach a record value of 130 V and 0.10 mA cm−2, respectively, giving over 10‐fold power enhancement, compared with the flat film‐based triboelectric nanogenerator.
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•Graphene used as support for active materials to improve catalytic activity.•NPs were loaded onto GO and thermally reduced to obtain both GO and rGO properties.•The surface ...functional groups of graphene improve NPs dispersion.•MnCe/GO-r/Ti catalyst shows high NOx removal efficiency of over 99% at low temperatures.
The MnCe oxides based catalysts with partially reduced graphene oxide support were synthesized, and the prepared catalyst exhibited high NOx removal characteristics at low temperatures. Generally, the graphene oxide has many functional groups on its surface which enables the enhanced dispersion behavior, whereas, the reduced graphene oxide can provide high specific surface area. In order to exploit the advantages graphene oxide and reduced graphene oxide, partially reduced graphene oxide support was synthesized by impregnating the active materials on graphene oxide and the graphene oxide support was further reduced with thermal reduction process. The prepared catalysts exhibited high NOx removal characteristics of 99% at the temperature range 150–300 °C, and further elucidated with TEM, BET, NH3-TPD, H2-TPR, and XPS analysis. By using the partially reduced graphene oxide support, we can synthesize a catalyst exhibiting high NOx removal efficiency with low content of active materials.
For existing triboelectric nanogenerators (TENGs), it is important to explore unique methods to further enhance the output power under realistic environments to speed up their commercialization. We ...report here a practical TENG composed of three layers, in which the key layer, an electric double layer, is inserted between a top layer, made of Al/polydimethylsiloxane, and a bottom layer, made of Al. The efficient charge separation in the middle layer, based on Volta's electrophorus, results from sequential contact configuration of the TENG and direct electrical connection of the middle layer to the earth. A sustainable and enhanced output performance of 1.22 mA and 46.8 mW cm
under low frequency of 3 Hz is produced, giving over 16-fold enhancement in output power and corresponding to energy conversion efficiency of 22.4%. Finally, a portable power-supplying system, which provides enough d.c. power for charging a smart watch or phone battery, is also successfully developed.
Ever since a new energy harvesting technology, known as a triboelectric nanogenerator (TENG), was reported in 2012, the rapid development of device fabrication techniques and mechanical system ...designs have considerably made the instantaneous output power increase up to several tens of mW/cm². With this innovative technology, a lot of researchers experimentally demonstrated that various portable/wearable devices could be operated without any external power. This article provides a comprehensive review of polyvinylidene fluoride (PVDF)-based polymers as effective dielectrics in TENGs for further increase of the output power to speed up commercialization of the TENGs, as well as the fundamental issues regarding the materials. In the end, we will also review PVDF-based sensors based on the triboelectric and piezoelectric effects of the PVDF polymers.
Highly stretchable 2D fabrics are prepared by weaving fibers for a fabric-structured triboelectric nanogenerator (FTENG). The fibers mainly consist of Al wires and polydimethylsiloxane (PDMS) tubes ...with a high-aspect-ratio nanotextured surface with vertically aligned nanowires. The fabrics were produced by interlacing the fibers, which was bonded to a waterproof fabric for all-weather use for fabric-structured triboelectric nanogenerator (FTENG). It showed a stable high-output voltage and current of 40 V and 210 μA, corresponding to an instantaneous power output of 4 mW. The FTENG also exhibits high robustness behavior even after 25% stretching, enough for use in smart clothing applications and other wearable electronics. For wearable applications, the nanogenerator was successfully demonstrated in applications of footstep-driven large-scale power mats during walking and power clothing attached to the elbow.
Junction networks made of longitudinally connected metal oxide nanowires (MOx NWs) have been widely utilized in resistive-type gas sensors because the potential barrier at the NW junctions leads to ...improved gas sensing performances. However, conventional MOx–NW-based gas sensors exhibit limited gas access to the sensing sites and reduced utilization of the entire NW surfaces because the NW networks are grown on the substrate. This study presents a novel gas sensor platform facilitating the formation of ZnO NW junction networks in a suspended architecture by growing ZnO NWs radially on a suspended carbon mesh backbone consisting of sub-micrometer-sized wires. NW networks were densely formed in the lateral and longitudinal directions of the ZnO NWs, forming additional longitudinally connected junctions in the voids of the carbon mesh. Therefore, target gases could efficiently access the sensing sites, including the junctions and the entire surface of the ZnO NWs. Thus, the present sensor, based on a suspended network of longitudinally connected NW junctions, exhibited enhanced gas response, sensitivity, and lower limit of detection compared to sensors consisting of only laterally connected NWs. In addition, complete sensor structures consisting of a suspended carbon mesh backbone and ZnO NWs could be prepared using only batch fabrication processes such as carbon microelectromechanical systems and hydrothermal synthesis, allowing cost-effective sensor fabrication.
High‐output triboelectric nanogenerators (TENGs) are demonstrated based on polyimide (PI)‐based polymers by introducing functionalities (e.g., electron‐withdrawing and electron‐donating groups) into ...the backbone. The TENG based on 6FDA‐APS PI, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, produces the highest effective charge density of about 860 µC m−2 in practical working conditions with the ion injection process. This may be ascribed to the excellent charge‐retention characteristics as well as the enhanced charge transfer capability, which increases the output power by 7 times compared to the commercially available Kapton film‐based TENG. Finally, a 6FDA‐APS‐driven sensor network system is demonstrated, providing the identity of three gases (H2, CO, and NO2) by illuminating the light‐emitting diodes within several seconds.
A polyimide‐based polymer based on 6FDA‐APS is synthesized for the effective dielectric of triboelectric nanogenerator (TENG). A maximum charge density of about 860 µC m−2 is obtained from the TENG, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, which leads to excellent charge retention characteristics and enhanced charge transfer capability. A 6FDA‐APS‐driven gas sensor network system is demonstrated.
Single silver nanowires produced by DC electrodeposition in porous anodic alumina templates were surface-functionalized with the bifunctional molecule 4-aminobenzenthiol (ABT) then exposed to aqueous ...silver nanoparticles resulting in a silver nanoparticle-decorated silver nanowire. The polarization dependent surface-enhanced Raman (SERS) signal from this system showed significant intensity anisotropy when measured at a midsection of the nanowire, where the largest SERS intensities were observed when the incident light was polarized perpendicular to the nanowire’s long axis but was almost isotropic near the tip of the nanowire. The observed effects were accounted for in terms of the electromagnetic fields concentrated in the collection of hot spots created through the ABT-linker-driven nanoparticle-nanowire self-assembly process.
Since 2012, a triboelectric nanogenerator (TENG) has provided new possibilities to convert tiny and effective mechanical energies into electrical energies by the physical contact of two objects. Over ...the past few years, with the advancement of materials' synthesis and device technologies, the TENGs generated a high instantaneous output power of several mW/cm
2
, required to drive various self-powered systems. However, TENGs may suffer from intrinsic and practical limitations such as air breakdown that affect the further increase of the outputs. This article provides a comprehensive review of high-output TENGs from fundamental issues through materials to devices. Finally, we show some strategies for fabricating high-output TENGs.
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