A triboelectric nanogenerator based on a spiral rotating shaft for efficient marine energy harvesting of the hydrostatic pressure differential

Equipment used in underwater sensing and exploration typically relies on cables or batteries for energy supply,resulting in a limited and inconvenient energy supply and marine environmental pollution that hinder the sustainable development of distributed ocean sensing networks.Here,we design a deep-sea differential-pressure triboelectric nanogenerator(DP-TENG)based on a spiral shaft drive using modified polymer materials to harness the hydrostatic pressure gradient energy at varying ocean depths to power underwater equipment.The spiral shaft structure converts a single compression into multiple rotations of the TENG rotor,achieving efficient conversion of differential pressure energy.The multi-pair electrode design enables the DP-TENG to generate a peak current of 61.7μA,the instantaneous current density can reach 0.69μA cm^(-2),and the output performance can be improved by optimizing the spiral angle of the shaft.The DP-TENG can charge a 33μF capacitor to 17.5 V within five working cycles.It can also power a digital calculator and light up 116 commercial power light-emitting diodes,demonstrating excellent output capability.With its simple structure,low production cost,and small form factor,the DP-TENG can be seamlessly integrated with underwater vehicles.The results hold broad prospects for underwater blue energy harvesting and are expected to contribute to the development of self-powered equipment toward emerging“smart ocean”and blue economy applications.

Dual-functional MnS_(2)/MnO_(2) heterostructure catalyst for efficient acidic hydrogen evolution reaction and assisted degradation of organic wastewater

The design and synthesis of non-precious metal dual-functional electrocatalysts through the modulation of electronic structure are important for the development of renewable hydrogen energy.Herein,MnS_(2)/MnO_(2)-CC heterostructure dual-functional catalysts with ultrathin nanosheets were prepared by a twostep electrodeposition method for efficient acidic hydrogen evolution reaction(HER) and degradation of organic wastewater(such as methylene blue(MB)).The electronic structure of Mn atoms at the MnS_(2)/MnO_(2)-CC heterostructure interface is reconfigured under the joint action of S and O atoms.Theoretical calculations show that the Mn d-band electron distribution in MnS_(2)/MnO_(2)-CC catalyst has higher occupied states near the Fermi level compared to the MnO_(2) and MnS_(2) catalysts,which indicates that MnS_(2)/MnO_(2)-CC catalyst has better electron transfer capability and catalytic activity.The MnS_(2)/MnO_(2)-CC catalysts require overpotential of only 66 and 116 mV to reach current density of 10 and 100 mA cm^(-2)in MB/H_(2)SO_(4) media.The MnS_(2)/MnO_(2)-CC catalyst also has a low Tafel slope(26.72 mV dec^(-1)) and excellent stability(the performance does not decay after 20 h of testing).In addition,the MB removal efficiency of the MnS_(2)/MnO_(2)-CC catalyst with a better kinetic rate(0.0226) can reach 97.76%,which is much higher than that of the MnO_(x)-CC catalyst(72.10%).This strategy provides a new way to develop efficient and stable non-precious metal dual-functional electrocatalysts for HER and organic wastewater degradation.

Triboelectric nanogenerator enhanced multilayered antibacterial nanofiber air filters for efficient removal of ultrafine particulate matter

We developed a high-efficiency rotating triboelectric nanogenerator （R-TENG）- enhanced multi.layered antibacterial polyimide （PI） nanofiber air filters for removing ultrafine particulate matter （PM） from ambient atmosphere. Compared to single- layered PI nanofiber filters, the multilayered nanofiber filter can completely remove all of the particles with diameters larger than 0.54 ffm and shows enhanced removal efficiency for smaller PM particles. After connecting with a R-TENG, the removal efficiency of the filer for ultrafine partides is further enhanced. The highest removal efficiency for ultrafine particulate matter is 94.1% at the diameter of 53.3 nm and the average removal efficiency reached 89.9%. Despite an increase in the layer number, the thickness of each individual layer of the film decreased, and hence, the total pressure drop of the filter decreased instead of increasing. Moreover, the nanofiber film exhibited high antibacterial activity because of the addition of a small amount of silver nanoparticles. This technology with zero ozone release and low pressure drop is appropriate for cleaning air, haze treatment, and bacterial control.

Triboelectrification induced UV emission from plasmon discharge

UV is a high-energy electromagnetic radiation that has been widely used in industrial production and the scientific research domain. In this work, a deep UV light emission was obtained using triboelectrification induced plasma discharge without any extra power supply. By a mechanical friction between polymer and quartz glass, the triboelectric charges cause a changing electric field, which may bring plasma discharge of low pressure gas （Ar-Hg） and give out 253.7 nm irradiation. The UV light caused by continuous friction can excite a trichromatic phosphor and afford a bright white light emission. A UV sterilization experiment shows that -98% of Escherichia coil can be killed in 30 min by UV irradiation, which reveals that a self-powered sterilization apparatus with good sterilization effect was fabricated. This work provides a novel design to fabricate a self- powered UV light emitting device using low-frequency mechanical friction and realizes the coupling of triboelectrificafion and plasma luminescence, which may further expand the application of UV light in special circumstances.

Cylindrical spiral triboelectric nanogenerator

In recent years, triboelectric nanogenerators have attracted much attention because of their unique potential in self-powered nanosensors and nanosystems. In this paper, we report a cylindrical spiral tdboelectric nanogenerator （S-TENG）, which not only can produce high electric output to power display devices, but also can be used as a self-powered displacement sensor integrated on a measurement ruler. At a sliding speed of 2.5 m/s, S-TENG can generate a short-circuit current （Isc） of 30 μA and an open-circuit voltage （Voc） of 40 V. As the power source, we fabricate a transparent and flexible hand-driven S-TENG. Furthermore, we demonstrate a self-powered S-TENG-based measuring tapeline that can accurately measure and display the pulled-out distance without the need for an extra battery. The results obtained indicate that TENG-based devices have good potential for application in self-powered measurement systems.