Electrosprayed boron nitride nanosheet aggregates for enhanced acoustic energy harvesting with poly(vinylidene fluoride) nanofiber membranes

While often regarded as an annoyance, noise conceals a surprisingly abundant source of untapped energy that can be efficiently harvested to power a variety of micro-devices. However, achieving high electric outputs from acoustic energy harvesters remains a formidable challenge. In this study, we employ a one-step approach that integrates electrospining and electrospraying techniques to fabricate a single-layer composite membrane, comprising a poly(vinylidene fluoride) (PVDF) nanofiber network with uniformly dispersed boron nitride nanosheet aggregates (BNNS-A) for sound energy harvesting. Our 3 × 4 cm2 +PVDF/-BN device generates peak voltage and current outputs of 174.2 V and 19.2 µA, respectively, when exposed to 115 dB, 230 Hz sound. Remarkably, this device exhibits the highest voltage output among other similar PVDF-based acoustoelectric devices operating under comparable sound conditions. Furthermore, the incorporation of BNNS-A enhances maximum peak power output by 30-fold compared to pure PVDF nanofiber devices. This study provides a profound understanding of endogenous triboelectricity mechanism in nanocomposites and presents a promising approach for producing high-performance nanofiber acoustoelectric devices

Nitrogen-Doped Oxygenated Molybdenum Phosphide as an Efficient Electrocatalyst for Hydrogen Evolution in Alkaline Media

Phosphides of transition metals (TMPs) are a developing class of materials for hydrogen evolution reaction (HER) as an alternative to expensive noble metals to produce clean energy. Herein, the nitrogen-doped molybdenum oxide (MoOx) is developed via a facile and simple hydrothermal method, followed by annealing in the N2 atmosphere and phosphorization to form a nitrogen-doped oxygenated molybdenum phosphide (N-MoP) sphere-shaped structure. The developed N-doped phosphide structure depicts enhanced HER activity by reaching a current density of 10 mA cm−2 at a very low overpotential of only 87 mV, which is much better than annealed nitrogen-doped molybdenum oxide (A-MoOx) 138 mV in alkaline medium. N-MoP is a highly efficient electrocatalyst for HER attributed to a more exposed surface, large electrode/electrolyte interface and appropriate binding energies for reactants. This study extends the opportunity of developing nitrogen-doped TMPs, which can display exceptional properties as compared to their oxides

Soft X-ray Detectors Based on SnS Nanosheets for the Water Window Region

The structural characteristics of biological specimens, such as wet proteins and fixed living cells, can be conveniently probed in their host aqueous media using soft X-rays in the water window region (200–600 eV). Conventional X-ray detectors in this area exhibit low spatial resolution, have limited sensitivity, and require complex fabrication procedures. Here, many of these limitations are overcome by introducing a direct soft X-ray detector based on ultrathin tin mono-sulfide (SnS) nanosheets. The distinguishing characteristic of SnS is its high photon absorption efficiency in the soft X-ray region. This factor enables the fabricated soft X-ray detectors to exhibit excellent sensitivity values on the order of (Formula presented.) at peak energies of ≈600 eV. The peak signal is found to be sensitive to the number of stacked SnS layers, with thicker SnS nanosheet assemblies yielding a peak response at higher energies and with peak sensitives of over 2.5 (Formula presented.) at 1 V. Detailed current–voltage and temporal characteristics of these detectors are also presented. These results showcase the excellent performance of SnS nanosheet-based soft X-ray detectors compared to existing direct soft X-ray detectors, including that of the emerging organic–inorganic perovskite class of materials