Piezo-Enhanced Photocatalytic Activity of the Electrospun Fibrous Magnetic PVDF/BiFeO(3) Membrane

Microwave-Assisted Synthesis of Flower-like MnMoO4 Nanostructures and Their Photocatalytic Performance

This article describes an affordable method for the synthesis of MnMoO4 nanoflowers through the microwave synthesis approach. By manipulating the reaction parameters like solvent, pH, microwave power, and irradiation duration along this pathway, various nanostructures can be acquired. The synthesized nanoflowers were analyzed by using a powder X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and UV-vis diffuse reflectance spectroscopy (UV-DRS) to determine their crystalline nature, morphological and functional group, and optical properties, respectively. X-ray photoelectron spectroscopy (XPS) was performed for the examination of elemental composition and chemical states by qualitative and quantitative analysis. The results of the investigations demonstrated that the MnMoO4 nanostructures with good crystallinity and distinct shape were formed successfully. The synthesized MnMoO4 nanoflowers were tested for their efficiency as a photocatalyst in the degradation studies of methylene blue (MB) as model organic contaminants in an aqueous medium under visible light, which showed their photocatalytic activity with a degradation of 85%. Through the band position calculations using the electronegative value of MnMoO4, the photocatalytic mechanism of the nanostructures was proposed. The results indicated that the effective charge separation, and transfer mechanisms, in addition to the flower-like shape, were responsible for the photocatalytic performance. The stability of the recovered photocatalyst was examined through its recyclability in the degradation of MB. Leveraging MnMoO4's photocatalytic properties, future studies may focus on scaling up these processes for practical and large-scale environmental remediation.

LiNbO3 Thin Films through a Sol-Gel/Spin-Coating Approach Using a Novel Heterobimetallic Lithium-Niobium Precursor

Lithium niobate is a lead-free material which has attracted considerable attention due to its excellent optical, piezoelectric, and ferroelectric properties. This research is devoted to the synthesis through an innovative sol-gel/spin-coating approach of polycrystalline LiNbO3 films on Si substrates. A novel single-source hetero-bimetallic precursor containing lithium and niobium was synthesized and applied to the sol-gel synthesis. The structural, compositional, and thermal characteristics of the precursor have been tested through attenuated total reflection, X-ray photoelectron spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The LiNbO3 films have been characterized from a structural point of view with combined X-ray diffraction and Raman spectroscopy. Field-emission scanning electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy have been used to study the morphological and compositional properties of the deposited films.

Synthesis, Characterization and Performance of Materials for a Sustainable Future

The current era has been defined as "The Plastic Era", considering that over the past 50 years the role and importance of polymeric materials in our economy has steadily grown, reaching a production of around a few hundred million tons per year which may even double in the next 20 years [...].

Piezoelectric polarization coupled with photoinduced catalytic oxidation technology for environmental pollution control: Recent advances and future prospects

Energy scarcity and environmental pollution concerns have become substantial impediments to sustainable global economic development. The advent of semiconductor photocatalysis technology provides a potential possibility for effectively alleviating excessive energy consumption and maintaining the long-term stability of the aqueous ecosystem. However, the inefficient transmission efficiency of charge carriers and the high recombination rate of photogenerated electron-hole pairs will culminate in the mediocre catalytic performance observed in conventional semiconductor materials. Fortunately, the piezo-photocatalysis ingeniously integrates the piezoelectric properties of piezoelectric crystals with the optoelectronic properties of semiconductors, thus building a theoretical system of photo-electric-chemical three-phase coupled catalysis. Currently, the photo-mechanical energy synergistic catalytic oxidation degradation process, as a cutting-edge technology based on clean renewable energy, has been perceived as a promising environmental remediation strategy. Herein, a critical review of the application of piezo-photocatalysis in environmental pollution control was delivered. We undertook a comprehensive analysis to elucidate the underlying enhancement mechanism of the piezoelectric effect on photocatalysis in terms of charge migration dynamics and pertinent energy band bending phenomena. In addition, we meticulously summarized diverse innovative methods for introducing vibration energy in piezo-photocatalytic degradation systems (ultrasound, fluid mechanical energy, airflow, self-assembled reactors, etc.). Then, state-of-the-art research advances in the field of environmental pollution control and the corresponding environmental decontamination mechanisms were elaborated based on various integration modes of catalysts (single component, noble metal deposition, heterojunction, coupled substrate materials, etc.). Eventually, an in-depth assessment of current limitations and development trends of piezo-photocatalytic degradation technology has been proposed, along with proactive strategies aimed at surmounting the existing challenges.

Combination NIPS/TIPS Synthesis of α-Fe2O3 and α/γ-Fe2O3 Doped PVDF Composite for Efficient Piezocatalytic Degradation of Rhodamine B

Highly porous membranes based on polyvinylidene fluoride (PVDF) with the addition of nanoscale particles of non-magnetic and magnetic iron oxides were synthesized using a combined method of non-solvent induced phase separation (NIPS) and thermo-induced phase separation (TIPS) based on the technique developed by Dr. Blade. The obtained membranes were characterized using SEM, EDS, XRD, IR, diffuse reflectance spectroscopy, and fluorescent microscopy. It was shown that the membranes possessed a high fraction of electroactive phase, which increased up to a maximum of 96% with the addition of 2 wt% of α-Fe2O3 and α/γ-Fe2O3 nanoparticles. It was demonstrated that doping PVDF with nanoparticles contributed to the reduction of pore size in the membrane. All membranes exhibited piezocatalytic activity in the degradation of Rhodamine B. The degree of degradation increased from 69% when using pure PVDF membrane to 90% when using the composite membrane. The nature of the additive did not affect the piezocatalytic activity. It was determined that the main reactive species responsible for the degradation of Rhodamine B were •OH and •O2-. It was also shown that under piezocatalytic conditions, composite membranes generated a piezopotential of approximately 2.5 V.

Polyvinylidene Fluoride/Aromatic Hyperbranched Polyester of Third-Generation-Based Electrospun Nanofiber as a Self-Powered Triboelectric Nanogenerator for Wearable Energy Harvesting and Health Monitoring Applications

Flexible pressure sensors have played an increasingly important role in the Internet of Things and human-machine interaction systems. For a sensor device to be commercially viable, it is essential to fabricate a sensor with higher sensitivity and lower power consumption. Polyvinylidene fluoride (PVDF)-based triboelectric nanogenerators (TENGs) prepared by electrospinning are widely used in self-powered electronics owing to their exceptional voltage generation performance and flexible nature. In the present study, aromatic hyperbranched polyester of the third generation (Ar.HBP-3) was added into PVDF as a filler (0, 10, 20, 30 and 40 wt.% w.r.t. PVDF content) to prepare nanofibers by electrospinning. The triboelectric performances (open-circuit voltage and short-circuit current) of PVDF-Ar.HBP-3/polyurethane (PU)-based TENG shows better performance than a PVDF/PU pair. Among the various wt.% of Ar.HBP-3, a 10 wt.% sample shows maximum output performances of 107 V which is almost 10 times that of neat PVDF (12 V); whereas, the current slightly increases from 0.5 μA to 1.3 μA. The self-powered TENG is also effective in measuring human motion. Overall, we have reported a simpler technique for producing high-performance TENG using morphological alteration of PVDF, which has the potential for use as mechanical energy harvesters and as effective power sources for wearable and portable electronic devices.