Search

Abstract Ferroelectric BaBi4Ti4O15 was prepared using solid-state calcination at 950 °C for four hours. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy were utilized to understand its microstructure and other structural aspects. Particle size was around

Abstract This study presents a novel approach to fabricating interdigitated capacitive (IDC) touch sensors using graphite-based pencils on a wood substrate. The sensors were designed to detect touches and pressure variations, offering a cost-effective and environmentally friendly solution for sensor fabrication. The fabrication process involved abrasion of graphite pencils on a wooden substrate to create conductive traces, followed by the integration of interdigitated electrode structures. Capacitance variations resulting from touch interactions were investigated to calibrate sensor responses for tailored tasks. The sensitivity of the sensor was found to be 1.2 pF/kPa, highlighting its responsiveness to pressure variations. Additionally, the sensors were interfaced with an Arduino Uno microcontroller board to demonstrate practical applications, such as replicating arrow key functionality. Additionally, the sensors exhibit sensitivity to environmental factors, with the relative change in capacitance increasing from 0.1 to 0.65 as relative humidity ranges from 30 to 90%. Furthermore, variations in temperature from 30 to 60ºC result in a relative change in capacitance increasing to approximately 0.5. The results indicate the feasibility and versatility of using wood-based substrates and graphite-based pencils for fabricating IDC touch sensors, offering promising prospects for sustainable and accessible sensor technology.

This research presents the fabrication and characterization of an interdigitated capacitive (IDC) sensor on a wooden substrate using pencil traces. The resistance of the pencil traces decreased from 100 kΩ to 5 kΩ as the pencil grade shifted from HB to 8B. Concurrently, capacitance measurements revealed an increase from approximately 5 pF for a 5-finger IDC made with HB pencil to around 32 pF for an 8B pencil counterpart. Increasing the number of pencil traces from 10 to 50 resulted in a significant decrease in resistance and a proportional increase in capacitance. Application of the IDC sensor demonstrated notable changes in capacitance upon proximity and touch, with a significant decrease upon removal. The interdigitated capacitance sensor exhibits good proximity effects and contact sensitivity in touch, with capacitance increasing exponentially from 0.3 pF (7 cm) to 1.2 pF (direct contact), highlighting its ability to detect objects with high precision. Additionally, environmental factors such as temperature and humidity influence capacitance values. These findings underscore the potential of pencil-drawn IDC sensors for responsive and adaptable applications in various fields.

Abstract The fabrication of a Poly (vinylidene fluoride) membrane (PVDF) and ceramic-assisted bismuth vanadate-polyvinylidene fluoride (BiVO4-PVDF) composite membrane was achieved through the utilization of the electrospinning technique. The composition and structure of the fabricated membranes were characterized by X-ray powder diffraction, Raman analysis, scanning electron microscopy, Thermo gravimetric analyzer, Fourier transform infrared spectroscopy, and UV–Vis spectroscopy techniques. The prepared polymeric membranes were then utilized for catalytic investigation and to explore, how structure affects catalytic activity using 5 mg/L, 10 mL methylene blue (MB) dye solution. Ultrasonication, visible light irradiation, and the combination were used to study piezocatalysis, photocatalysis, and piezo-photocatalysis, moreover, degradation intermediates were also explored using scavengers. Electrospun BiVO4-PVDF (BV-PVDF) composite has been found to have better piezocatalytic and photocatalytic properties than PVDF. The experimental findings reveal that the composite of BiVO4-PVDF demonstrates the highest efficiency in dye degradation, achieving a maximum degradation rate of 61% within a processing time of 180 min. The rate of degradation was calculated to be 0.0047 min−1, indicating a promising potential for the composite in the field of dye degradation.

Abstract The mechanochemical ball milling followed by heating at 650 °C for 5 h successfully produced the single-phase Bi2VO5.5 powder. Catalytic activity for methylene blue dye degradation was investigated. Raman spectroscopy and X-ray diffraction were used to confirm the phase formation. The sample’s charge carrier transportation behavior was ascertained using time-dependent photocurrent analysis. The piezo-photocatalysis experiment yielded a 63% degradation efficiency for the ball-milled Bi2VO5.5 sample. The pseudo-first-order kinetics of the piezo-photocatalytic dye degradation are discerned, and the significant k value of 0.00529 min−1 is achieved. The scavenger test declares the h+ radical is the predominant active species during the piezo-photocatalysis experiment. Vigna radiata seeds were used in a phytotoxicity test to evaluate the germination index. The mechanochemical activation method facilitates reactions by lowering reaction temperature and time. The effect of improved piezo-photocatalytic efficiency on the ball-milled Bi2VO5.5 powder is an unexplored area, and we have attempted to investigate it. Here, ball-milled Bi2VO5.5 powder achieved improved dye degradation performance.

Abstract A thermoregulating smart textile based on phase change material (PCM) polyethylene glycol (PEG) was prepared by chemically grafting carboxyl-terminated PEG onto cotton. Further deposits of graphene oxide (GO) nanosheets were made on the PEG grafted cotton (PEG-g-Cotton) to improve the thermal conductivity of the fabric and to block harmful UV radiation. The GO-PEG-g-Cotton was characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and field emission-scanning electron microscopy (FE-SEM). With an enthalpy of 37 and 36 J/g, respectively, the DSC data revealed that the functionalized cotton's melting and crystallization maxima occurred at 58 °C and 40 °C, respectively. The thermogravimetric analysis (TGA) presented that GO-PEG-g-Cotton was thermally more stable in comparison to pure cotton. The thermal conductivity of PEG-g-Cotton increased to 0.52 W/m K after GO deposition, while pure cotton conductivity was measured as 0.045 W/m K. The improvement in the UV protection factor (UPF) of GO-PEG-g-Cotton was observed indicating excellent UV blocking. This temperature-regulating smart cotton offers a high thermal energy storage capability, better thermal conductivity, thermal stability, and excellent UV protection.

0.5Ba (Zr0.2Ti0.8)O3-0.5(Ba0.7Sr0.3)TiO3 (BST-BZT) ceramic composition is known for exihibiting electrical properties. The present study brings out the prospective approach of utilizing well known BST-BZT ceramic composition for water cleaning application via piezocatalysis, photocatalysis and piezo-photocatalysis process. For this, BST-BZT ceramic composition was synthesized through solid state route reaction method and was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Methylene Blue (MB) a cationic dye was used as a representative organic pollutant, where the maximum degradation was observed in piezo-photocatalysis process (∼92%) followed by photocatalysis process (∼82%) and piezocatalysis process (∼65%) in 240 min. Furthermore, the degradation of MB dye was examined under solar light irradiation in order to assess the potential of the BST-BZT ceramic composition. A study on the BST-BZT ceramic composition's photocatalytic activity in an indoor setting was also conducted. Finally, the phytotoxicity level of “Vigna radiata” seeds was examined to determine the extent of MB dye breakdown and its subsequent usage.

Abstract Finite element studies were conducted on 0.5Ba(Zr0.2 Ti0.8) O3–0.5(Ba0.7 Ca0.3)TiO3 (BCZT) piezoelectric particles embedded in polyethylene matrix to create a piezocomposite having a positive and negative Poisson's ratio of −0.32 and 0.2. Polyethylene with a positive Poisson's ratio is referred to as non-auxetic while those with negative Poisson's ratio are referred to as auxetic or inherently auxetic. The effective elastic and piezoelectric properties were calculated at volume fractions of (4%, 8% to 24%) to study their sensing and harvesting performance. This study compared lead-free auxetic 0–3 piezocomposite for sensing and energy harvesting with non-auxetic one. Inherently auxetic piezocomposites have been studied for their elastic and piezoelectric properties and improved mechanical coupling, but their sensing and energy harvesting capabilities and behavior patterns have not been explored in previous literatures. The effect of Poisson's ratio ranging between −0.9 to 0.4 on the sensing and energy harvesting performance of an inherently auxetic lead free piezocomposite composite with BCZT inclusions has also not been studied before, motivating the author to conduct the present study. Auxetic piezocomposite demonstrated an overall improvement in performance in terms of higher sensing voltage and harvested power. The study was repeated at a constant volume fraction of 24% for a range of Poisson's ratio varied between −0.9 to 0.4. Enhanced performance was observed at the extreme negative end of the Poisson's ratio spectrum. This paper demonstrates the potential improvements by exploiting auxetic matrices in future piezocomposite sensors and energy harvesters.

Abstract Quartz crystals are found in nature. It is believed that these crystals are eco‐friendly and known for healing, decoration, and gem therapy. However, there is no scientific evidence of such effects, except it is a piezoelectric material. The piezocatalytic effect is viewed as having significant potential for tackling environmental challenges such as water cleaning. The piezocatalytic performance of Quartz crystals was examined and reported for a few dyes degradation. The purity of these crystals was confirmed via X‐ray diffraction, Raman spectroscopy, and X‐ray photoelectron spectroscopy analysis before experimentation. Degradation of organic dyes methylene blue, methylene violet, and Rhodamine b (RB) dyes from aqueous solutions was observed using these crystals. Naturally occurred Quartz was exposed to ultrasonic vibrations for dyes and its piezocatalytic property was studied. Furthermore, using the germination index of Cicer arientium the treated water was utilized as a growth parameter. The signature of dye degradation indicates their eco‐friendly behavior. It can be assumed that these crystals can actively participate to clean organic pollutants under the application of mechanical vibrations.

The presence of toxic compounds in waste leads to unfavorable hazardous properties, there is an urgent urge for the remediation of environmental contamination. This work focuses on the removal of organic pollutants from the water. Piezocatalytic properties of transparent glass nanocomposites of Bi2ZnB2O7 (BBZO) were studied for water-cleaning application. Melt quenching followed by heat treatment of fabricated glass-nanocomposites were able to degrade different organic dyes. To study the microstructure of the samples under consideration, X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) were performed. To get the elemental composition of the glass nanocomposite samples, XPS (X-ray photoelectron spectroscopy) was utilized. Methylene blue (MB) dye was used as a model dye for degradation, and it is found that heat-treated glass nanocomposite sample at 475 °C for 1 h (HT/475 °C/1hr) gives maximum dye degradation of 78% under 240 min of ultrasonication with a degradation rate of 0.0065min−1. Furthermore, an obtained by-product from degraded dye was used to experiment to study phytotoxicity assessment using brown gram seeds and it has been found that treated water with BBZO HT/475 °C/1hr sample gives less phytotoxicity of water (Germination Index is found to be 88%).

This study comprises the combined effect of piezocatalytic and photocatalytic activity to obtain improved piezo-photocatalytic dye degradation efficiency in visible light. Single-phase Bi2VO5.5 powder was prepared through solid-state synthesis at 750 °C in 8 h. Time-dependent photocurrent responses were conducted to understand the phenomenon of charge carrier transport in visible light. Bi2VO5.5 powder sample demonstrated high photocatalytic efficiency and good reusability possessing a bandgap value of 2.13 eV. Bi2VO5.5 powder sample attained ∼70% and ∼58% degradation efficiency during photocatalysis and piezocatalysis respectively. The piezo-photocatalytic methylene blue dye attained ∼82% degradation efficiency in 240 min duration of visible light illumination. The scavenger test depicted holes (h+) as the principal active species in the piezo-photocatalytic dye degradation. There incurred no severe loss in photocatalytic efficiency even after 4 cycles which proclaims the reusability of the Bi2VO5.5 powder sample. A study on the kinetic rate constant with varying dye concentrations was conducted. With varied dye concentration of 5, 10, 15 mg/L, the kinetic rate constant obtained was 0.00528, 0.0030, and 0.00125 min−1, respectively. Germination index was found through a phytotoxicity test using vigna radiata seeds. Here visible light along with mechanical energy has been used to achieve higher MB dye degradation efficiency through piezo-photocatalysis.

Paper and pencil have shown wide applicability in the area of flexible electronics. Devices based on paper and pencil offer distinctive advantages, including rapid, straightforward, and cost-effective fabrication, as well as recyclability and eco-friendly characteristics. There are several concepts that have been demonstrated using paper and pencil including thermoelectric, strain gauges, capacitive sensors, and biomedical devices. This review article summarizes state of art of pencil-based thermoelectric devices on paper and their future potential.

Transparent glass-ceramics of CaO–Bi2O3–B2O3 (CBBO) were fabricated using the conventional melt quench technique. X-ray diffraction and Raman spectroscopy were employed to confirm the phase of the prepared samples. Differential scanning calorimetry (DSC) was used to verify that the material was, indeed, glassy. The CBBO glass samples were subjected to heat treatment at 540 °C for 30 min and 1 h based on their crystallization temperature obtained from DSC analysis. This study focused on the piezocatalytic behavior of CBBO glass-ceramic samples. Piezocatalysis experiments were conducted on the fabricated glass-ceramic samples, and it was discovered that the samples heat-treated for 30 min (HT30m) at 540 °C showed maximum dye degradation of 61% under 240 min of ultrasonication. Experiments were repeated multiple times to confirm their reliability. Additionally, a phytotoxicity assessment was performed on the degraded dye using vigna radiata seeds. The antibacterial properties of the CBBO glass-ceramic samples were also investigated via piezocatalysis. It was discovered that the HT30m CBBO glass-ceramic sample removes 98% of Escherichia coli and 99% of Staphylococcus aureus bacteria within 120 min of ultrasonication.

Barium Titanate (BaTiO3) nanoparticles were mixed with a stock paste containing an acrylate-based binder to prepare pigment paste. The formulated paste was applied to the cotton fabric by utilizing screen printing followed by drying and curing. The coated fabric was characterized for surface and elemental composition and uniform deposition of BaTiO3 nanoparticles was observed with minimal agglomeration. The resultant fabric showed an effective bacterial reduction greater than 99% against Escherichia coli and Staphylococcus aureus, and after 15 laundering cycles, the modified fabric showed a bacterial reduction of over 98%. The loaded fabric is capable of blocking harmful ultraviolet (UV) radiations. The modification of the cotton surface did not significantly change its intrinsic properties like water vapor permeability, air permeability, fabric stiffness, and other mechanical properties. The developed product has considerable possibilities and provides a good substitute for antibiotic materials for use in medical products and everyday apparel.

Abstract This paper presents a piezoelectric wind energy harvester that operates by a galloping mechanism with different shaped attachments attached to a bluff body. A comparison is made between harvesters that consist of different shaped attachments on a bluff body; these include triangular, circular, square, Y‐shaped, and curve‐shaped attachments. Simulation of the pressure field and the velocity field variation around the different shaped bluff bodies is performed and it is found that a high pressure difference creates a high lift force on the bluff body with curve‐shaped attachments. A theoretical model based on a galloping mechanism is presented, which is verified by experiments. It is observed that the proposed harvester with curve‐shaped attachments provides the best performance, where the harvester with a curve‐shaped attachments provides the highest voltage and power output compared to the other shaped harvesters examined in this study. This paper provides a new concept for improving the power performance of the piezoelectric wind energy harvesters with modifications made on the bluff body.

Abstract A single‐phase Bi2VO5.5 powder is formed effectively through a mechanochemical ball milling approach at 650 °C in 5 h and its photocatalytic performance on methylene blue dye is explored. X‐ray diffraction and Raman spectroscopy analytical instruments are utilized to confirm the phase formation. The evident presence of irregular‐shaped grains is affirmed using a scanning electron microscope. To ascertain the chemical condition of the components present, the Bi2VO5.5 powdered sample undergo an X‐Ray photoelectron spectroscopy investigation. The sample is analyzed using a time‐dependent photocurrent to discern its charge carrier transportation behavior. A photocatalytic study using Bi2VO5.5 powder produced through the mechanochemical ball milling method has not been explored till now. The efficacy of the ball‐milled Bi2VO5.5 powder to attain enhanced photocatalytic efficiency which hasn't been investigated till now, is explored. The ball‐milled Bi2VO5.5 sample achieved 70% degradation efficiency when performing the photocatalysis investigation. The photocatalytic dye degradation discerns pseudo‐first‐order kinetics and achieves a notable k value of 0.00636 min−1. The scavenger test indicates that h+ radicals are the prominent active species during the photocatalysis experiment. The germination index is determined by conducting a phytotoxicity test with the use of Vigna radiata seeds. Here ball‐milled Bi2VO5.5 powder attains enhanced dye degradation efficiency.

Abstract This study focuses on analyzing the poling effect of BaBi4Ti4O15 (BBT) on the basis of photo and piezo‐catalysis performance. BBT powder is prepared via a solid state reaction followed by calcination at 950 °C for 4 h. BBT is characterized by an X‐ray diffractometer, scanning electron microscopy, Raman spectroscopy, and X‐ray photoelectron spectroscopy. The optical bandgap of BBT is evaluated with the help of Tauc's plot and found to be 3.29 eV, which comes in the photon energy range of ultra‐violet radiation. BBT powder is poled by using Corona poling in the presence of 2 kV mm−1 of electric field. An aqueous solution of methyl blue (MB) dye in the presence of UV radiation is used to evaluate the photo/piezocatalysis performance. Photocatalysis, piezocatalysis, and photo–piezo catalysis degradation efficiencies of poled and unpoled BBT powder are tested for 120 min of UV light irradiation. Photo–piezocatalysis shows degradation efficiencies of 62% and 40% for poled and unpoled BBT powder, respectively. Poling of BBT powder shows significant enhancement in degradation performance of MB dye in aqueous solution. Scavenger tests are also performed to identify reactive species.

Abstract In the present numerical simulation work, effective elastic and piezoelectric properties are calculated and a comparative study is conducted on a cement matrix‐based piezocomposite with 0–3 and gyroid triply periodic minimal surface (TPMS) inclusions. The present study compares the effective properties of different piezoelectric materials having two different types of connectivity of the inclusions namely, 0–3 inclusions where the inclusions are physically separated from each other and are embedded within the matrix and the second one is TPMS inclusions having interpenetrating phase type connectivity. Effective properties are calculated for four different materials at five different volume fractions namely, 10%, 15%, 20%, 25%, and 30% volume fractions of inclusion by volume. In terms of effective properties and direct piezoelectric effect, TPMS piezocomposite is found to perform better compared to 0–3 piezocomposite. Lead‐free piezoelectric material 0.5Ba(Ca0.8Zr0.2)O3 − 0.5(Ba0.7Ca0.3)TiO3 demonstrates better performance compared to all other material inclusions studied. The present study attempts to highlight improved piezoelectric effective properties of lead‐free material‐based piezocomposites with TPMS inclusions.

Flexoelectricity is a symmetry independent electromechanical coupling phenomenon that outperforms piezoelectricity at micro and nanoscales due to its size-dependent behavior arising from gradient terms in its constitutive relations. However, due to this gradient term flexoelectricity, to exhibit itself, requires specially designed geometry or material composition of the dielectric material. First of its kind, the present study put forward a novel strategy of achieving electric field gradient and thereby converse flexoelectricity, independent of geometry and material composition of the material. The spatial variation of the electric field is established inside the dielectric material, Ba0.67Sr0.33TiO3 (BST), by manipulating electrical boundary conditions. Three unique patterns of electrode placement are suggested to achieve this spatial variation. This varying direction of electric field gives rise to electric field gradient, the prerequisite of converse flexoelectricity. A multi-physics coupling based theoretical framework is established to solve the flexoelectric actuation by employing isogeometric analysis (IGA). Electromechanically coupled equations of flexoelectricity are solved to obtain the electric field distribution and the resulting displacements thereby. The maximum displacements of 0.2 nm and 2.36 nm are obtained with patterns I and II, respectively, while pattern III can yield up to 85 nm of maximum displacement.

Abstract Reduced graphene oxide (rGO)/bismuth vanadate BiVO4 composites are fabricated with varied rGO amounts (0, 1, 2, and 3 wt%) through the synergetic effects of ultrasonication, photoinduced reduction, and hydrothermal methods, and the materials are tested as tools for sonophotocatalytic methylene blue (MB) dye degradation. The effect of rGO content on the sonophotocatalytic dye degradation capabilities of the composites are explored. Characterization of the proposed materials is done through transmission electron microscopy (TEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy as well as scanning electron microscopy. The coexistence of BiVO4 and rGO is confirmed using Raman spectroscopy and XRD. TEM confirms the existence of interfaces between rGO and BiVO4 and XPS affirms the existence of varied elemental oxidation states. In order to investigate the charge carriers transportation, time‐dependent photocurrent responses of BiVO4 and 2 wt%‐ rGO/BiVO4 are done under visible light irradiation. The sonophotocatalytic MB dye degradation in an aqueous medium displays promising enhancement with rGO doping in rGO/BiVO4 composite. The 2 wt%‐ rGO/BiVO4 sample exhibits ≈52% MB dye degradation efficiency as compared to pure BiVO4 (≈25%) in 180 min of the sonophotocatalysis experiment. Phytotoxicity analysis through germination index is done using vigna radiata seeds.

In piezocatalysis, the polarization field found in piezoelectric materials enables and enhances catalytic redox reactions. Here, piezocatalysis is demonstrated for organic dye degradation in wastewater for a SiO2–LiNbO3 ferroelectric glass–ceramic.

Composites of Plaster of Paris (POP)-BiOCl (%) are prepared by adding BiOCl of 0%, 1%, 5%, 10% and 20% (by wt.) in the POP matrix. The band gap of the BiOCl powder is calculated about 3.31 eV. Resazurin (Rz) ink is used as an indicator to monitor the photocatalytic activity and self-cleaning property of POP-BiOCl (%) composites under the visible light and the resultant decolourisation of Rz ink is directly related to the photocatalytic performance of the material. Optical images of the coating of Rz ink over the surfaces of POP-BiOCl (%) composite pellets confirmed a steady color change from blue to pink within 60 min time duration. Finally, the rate of decolourisation of Rz ink was calculated by measuring the absorption at two wavelengths (581 nm and 630 nm). Digital photographic methods as well as UV–visible absorption studies are performed to examine qualitative and quantitative decolourisation of the Rz ink.

Paper is one of the most ubiquitous materials. In the present work, it is employed as a flexible, inexpensive, degradable, lightweight and eco-friendly substrate for solvent-free fabrication of the Inter Digitated Capacitor (IDC). IDCs are employed in many sensing and energy harvesting applications recently, thus it was imperative to find a technique to fabricate IDCs using environment friendly and biodegradable processes. With fixed and controlled parameters, Butter paper exhibits the lowest resistance and maximum capacitance which were almost 1 kΩ and in the range of 20–30 pF respectively. Additionally, maximum capacitance per unit area was achieved through configuring the shape of graphite electrodes and it was observed that semi-circular geometry exhibits maximum capacitance, giving a value of almost 60 pF. Furthermore, the investigation has been made on green fabrication process to get the range of scalability and tune-ability of the capacitance of IDCs by impregnating Butter Papers in NaCl solution and also talking about the saturation point of these solutions, post which the IDCs start behaving erraticaly.The capacitance value in this case shows extrememly positive results and we managed to obtain a value of 18 nF which was a significant jump when compared to the untreated samples, which exhibted capacitance values in the range of pico-farads. Thus, it was discovered that Butter Paper(BP) could potentially function as a feasible and promising choice for flexible electronics.

Eggshells have been reported to generate huge tons of waste globally owing to their increasing consumption. Apart from its dietary benefits, the use of eggshell waste as a catalyst, filler in soil-cement bricks, dental cement, bone filler, etc. has been widely reported. This study uses a heat-treated eggshell by extracting calcium oxide, CaO, to prepare cement antibacterial composites. Thermogravimetric Analysis (TGA), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS or EDX), and Fourier transform infrared (FTIR) characterization techniques were used to understand the changes in the eggshell upon heat-treatment. Pure CaO obtained by heating eggshell at 900 °C was also examined for antibacterial activity against E.Coli and was found to be highly effective. CaO derived from eggshell was replaced with 5%, 10%, and 15% of cement weight of mortar and studied for antibacterial activity. It was observed that with increasing CaO content, the capacity of the specimen to kill bacteria increased on the surface. This usage of heat-treated eggshell in mortar can be a potential antibacterial composite. The novelty of this work highlights the use of heat-treated eggshell in preparation of antibacterial composites.

A ferroelectric Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZTO) ceramic was prepared using a solid-state reaction route. A coating of candle soot was provided on poled and unpoled BCZTO samples. X-ray diffraction and Raman spectroscopy confirmed the presence of the graphite form of carbon in the candle soot. Scanning Kelvin probe microscopy determined that the highest surface potentials were ∼34 mV and 1.5 V in the unpoled and poled BCZTO samples, respectively. The candle soot was found to adsorb ∼65%, 80%, and 90% of the methylene blue dye present in acidic, neutral, and basic media, respectively, within 3 h. In both the poled and unpoled cases, the BCZTO samples coated with candle soot showed greater adsorption capacities than the uncoated BCZTO sample. In the cases of poled samples coated with candle soot, the adsorption was found to be greater in the case of candle soot coated on a positively charged surface than that for candle soot coated on a negatively charged BCZTO surface in an acidic medium. In a basic medium, the adsorption was found to be greater in the case of candle soot coated on a negatively charged surface than that for candle soot coated on a positively charged BCZTO surface. The contact angle of the candle soot-coated BCZTO sample was found to be hydrophobic (∼149°). The contact angle decreased (∼149–133°) with an increase in temperature (30–70 °C) in the case of candle soot coated on the positive surface of a poled BCZTO sample. The contact angle increased (∼139–149°) with an increase in temperature (30–70 °C) in the case of candle soot coated on the negative surface of a poled BCZTO sample. Internal electric field-assisted (associated with ferroelectric materials) adsorption could be a potential technique to improve adsorption processes. Keywords: Ferroelectric, Hydrophobic, Adsorption, Candle soot, Poling

In this study, a method for the bacterial disinfection of drinking water in the water storage systems based on the electric potential generated from a piezoelectric wind energy harvester is presented. First, an efficient galloping piezoelectric wind energy harvester is designed by adding curve- shaped attachments to the bluff body of the harvester. The simulated output voltage of the harvester is validated by performing different sets of experiments on an open environment. Later, the output voltage of the harvester is enhanced, using copper oxide nanowires (CuONWs) grown perpendicular to the surface of the center copper wire. The enhanced electric field is able to disinfect the bacterial water in a 25 min time period. The bacterial removal log efficiency of 2.33 is obtained with a supplied rms voltage of 0.1 V from the harvester. The findings of this study will help to provide alternate means to water treatment that are efficient, reliable, and also free from disinfection by-products.

Abstract Piezoelectric materials play an important role in powering nano and microelectromechanical systems. However, these are often limited by their low sensing, actuation, and power outputs. This study proposes a novel poling direction arrangement theoretically in the piezoelectric materials which enhances the output parameters drastically. The poling angle was graded from bottom to top surface of element in linear fashion which helps in utilizing the bending and shear stresses efficiently. The sensing, actuation and energy harvesting performance of Pb[ZrxTi1‐x]O3 in graded mode was compared with those obtained from operating in transverse and shear modes. It was found from finite element simulations that a maximum sensing voltage of 11.85 V was been obtained in graded mode which was around 15 times higher than that obtained in shear mode. Likewise, a maximum strain of 8.2 μm/m and a tip displacement of 34.3 μm was observed in the graded mode. Eventually, the maximum power of 0.12 W was harvested from graded mode harvester followed by shear mode harvester where only : 1.6 × 10−3 W could be harvested. However, the associated challenge with such study is the fabrication and graded poling of piezoelectric which still is an unexplored research area for scientific fraternity.

Abstract This article reports the thermoelectric‐based solar energy harvesting. The effect of candle soot (CS) coating on solar energy harvesting potential of thermoelectric modules is studied. To compare the performance, uncoated/coated modules are exposed to solar radiations (through Fresnel lens) and the other side is kept at lower temperature using continuous water flow. Substantial enhancements in electrical outputs are observed due to CS coating on the upper surface of the thermoelectric module. The open‐circuit voltage and short‐circuit current across coated module improve more than six times in comparison to the uncoated module with maximum voltage and current reaching up to 1.5 V and 14 mA. Similarly, the generator can deliver a maximum power of 10 mW across a resistance of 50 Ω. Results indicate that the CS coating is an effective technique to improve the performance of thermoelectric materials for running sensors and other low‐power electronic devices.

A BiF3 powder sample was prepared from the purchased Bi2O3 powder via the precipitation route. The photocatalytic performance of the prepared BiF3 powder was compared with the Bi2O3 powder and recognized as superior. The prepared BiF3 powder sample was added in a plaster of Paris (POP) matrix in the proportion of 0%, 1%, 5%, and 10% by wt% to form POP–BiF3(0%), POP–BiF3(1%), POP–BiF3(5%), and POP–BiF3(10%) composite pellets, respectively, and activated the photocatalytic property under the UV–light irradiation,in the POP. In this work, Resazurin (Rz) ink was utilized as an indicator to examine the photocatalytic activity and self-cleaning performance of POP–BiF3(0%), POP–BiF3(1%), POP–BiF3(5%), and POP–BiF3(10%) composite pellets. In addition to the digital photographic method, the UV–visible absorption technique was adopted to quantify the rate of the de-colorization of the Rz ink, which is a direct measure of comparative photocatalytic performance of samples.

Abstract Pyroelectric performance is significantly improved using a coating of diesel exhaust soot. Coated pyroelectric sample (lead zirconate titanate) is exposed to a temporal temperature gradient. Under the application of infrared (IR) heating for a given temperature gradient, the maximum open circuit voltage improves more than four times, electric current across a resistance of 10 ohm improves more than six times, and the stored energy in 10 µF capacitor is enhanced by 17 times. These results are important from two aspects: 1) utilization of waste diesel exhaust soot and 2) improving energy harvesting performance of pyroelectric materials.

Temperature-dependent ferroelectric behavior in Ba0.85Ca0.15Ti0.9−xFexZr0.1O3 (BCT-BZT-Fe) (x = 0%, 0.5%, 1%) has been investigated. Olsen cycle is used to estimate the thermal energy conversion potential in the compositions under study. The maximum energy conversion density of 305 kJ/m3 per cycle is obtained for BCT-BZT-Fe (0.5% Fe content) when the cycle is operated between 30 and 110 °C and an electric field of 0–3 MV/m. The obtained energy density is very high for small electric field and temperature gradient as compared to other lead-free ferroelectric materials. A comparison table of previously reported Olsen cycle-based energy conversion in bulk ferroelectric ceramics is presented. Temperature also affects the hysteresis parameters, therefore, scaling relations for coercive field (Ec) and remnant polarization (Pr) as a function of temperature (T) were also observed. The power-law exponents are obtained for all hysteresis parameters in the compositions under study. The scaling relations are found as Ec ∝ T−0.658, Ec ∝ T−0.687 and Ec ∝ T−0.717 for 0%, 0.5% and 1% Fe, respectively. Similarly, Pr ∝ T−1.59, Pr ∝ T−1.65 and Pr ∝ T−1.85 are for 0%, 0.5% and 1% Fe, respectively. Additionally, back-switching polarization (Pbc) behavior as a function of temperature is estimated by well-described Arrhenius law to evaluate the average activation energy for all the compositions.

This paper deals with a study of Ba0.85Ca0.15−xSrxTi0.9Zr0.1O3 (BCT-BZT-Sr) (x = 0%, 5%, 10% and 15%) polycrystalline ceramics for thermal energy conversion applications using the Olsen cycle. A maximum energy conversion density of 108 kJ/m3 was observed in pristine BCT-BZT for cycle operating at 30–90 °C and 0–20 kV/cm. Moreover, the samples with Sr contents (x) of 5%, 10% and 15% display an energy conversion density of 179 kJ/m3, 149 kJ/m3 and 200 kJ/m3, respectively. The Sr addition almost double the energy conversion over the pristine sample under the similar conditions. Also, the temperature (T)-dependent dynamic hysteresis scaling relations for coercive field (EC) and remnant polarization (Pr) were systematically investigated. The power-law scaling exponents are obtained for EC versus T as EC ∝ T−0.65, EC ∝ T−0.61, EC ∝ T−0.56 and EC ∝ T−0.63 for the samples with Sr contents of 0%, 5%, 10% and 15%, respectively. Similarly, the scaling relations for Pr are Pr ∝ T−1.59, Pr ∝ T−1.59, Pr ∝ T−1.36 and Pr ∝ T−1.32 for the samples with Sr contents of 0%, 5%, 10% and 15%, respectively.