Facile Sol-gel Technique Research Articles

Thiram Determination in Milk Samples by Surface Plasmon Resonance Based on Molecularly Imprinted Polymers and Sulphur-Doped Titanium Dioxide.

In this work, a new surface plasmon resonance (SPR) sensor based on sulphur-doped titanium dioxide (S-TiO2) nanostructures and molecularly imprinted polymer (MIP) was presented for thiram (THI) determination in milk samples. Firstly, the S-TiO2 nanomaterial with a high product yield was prepared by using a facile sol-gel hydrolysis technique with a high product yield. After that, UV polymerization was carried out for the preparation of the THI-imprinted SPR chip based on S-TiO2 using a mixture including ethylene glycol dimethacrylate (EGDMA) as the cross-linker, N,N'-azobisisobutyronitrile (AIBN) as the initiator, and methacryloylamidoglutamicacid (MAGA) as the monomer. The reliability of the sensor preparation procedure has been successfully proven by characterization studies of the prepared nanomaterials and SPR chip surfaces through spectroscopic, microscopic, and electrochemical methods. As a result, the prepared SPR sensor showed linearity in the range of 1.0 × 10-9-1.0 × 10-7 M with a detection limit (LOD) of 3.3 × 10-10 M in the real samples, and a sensor technique for THI determination with high sensitivity, repeatability, and selectivity can be included in the literature.

Sol-Gel Derived ZnO Thin Films with Nonvolatile Resistive Switching Behavior for Future Memory Applications

Herein we report on a facile sol-gel spin-coating technique to fabricate ZnO thin films that grow preferentially along the (002) plane on FTO substrates. By employing the magnetron sputtering technique to deposit a tungsten (W) top metal electrode onto these ZnO thin films, we successfully realize a W/ZnO/FTO memory device that exhibits self-rectifying and forming-free resistive switching characteristics. Notably, the as-prepared device demonstrates impressive nonvolatile and bipolar resistive switching behavior, with a high resistance ratio (RHRS/RLRS) exceeding two orders of magnitude at a reading voltage of 0.1 V. Moreover, it exhibits ultralow set and reset voltages of approximately +0.5 V and −1 V, respectively, along with exceptional durability. In terms of carrier transport properties, the low resistance state of the device is dominated by ohmic conduction, whereas the high resistance state is characterized by trap-controlled space-charge-limited current conduction. This work highlights the potential of the ZnO-based W/ZnO/FTO memory device as a promising candidate for future high-density nonvolatile memory applications.

Enhancing anti-fouling performance of ceramic membranes through iron oxide modification for the separation of oil-containing fermentation broth

Ceramic membranes are increasingly recognized for their effectiveness in processing fermentation broths. However, developing ceramic membranes with superior anti-fouling properties remains a challenge for large-scale applications. Iron oxide nanomaterials have gained significant research interest as a cost-effective and readily available solution for mitigating membrane fouling, thanks to their excellent hydrophilicity. This study introduces ceramic membranes enhanced with iron oxide via a facile sol-gel technique. The membrane's resistance to fouling, hydrophilicity, adhesion force, and surface potential were assessed. Post-modification, a consistent distribution of iron elements on the membrane surface was achieved, with negligible alteration in pore size. Although the pure water permeance (450 ± 45 L m−2 h−1·bar−1) did not change significantly, the permeance of the modified membrane (225 L m−2 h−1·bar−1) was nearly 20 % higher than that of the original membrane when separating a 1000 ppm oil-in-water emulsion, with both membranes achieving 99 % oil droplet rejection. Moreover, the flux recovery rate of the modified membrane surpassed that of the original membrane by approximately 30 %, indicating a significant improvement in anti-fouling performance. Upscaling experiments further validated the modified membrane's anti-fouling performance and capability to rapidly process broths with high oil content. Overall, this study presents a novel anti-fouling ceramic membrane for the treatment of oil-containing fermentation systems.

Green energy generation via water splitting by non-photocatalytic process based on Gd doped magnesium ferrite hydroelectric cells

This study presents compelling empirical evidence that highlights the notable effect of increased defect concentration on the splitting of water molecules in MgGdxFe2-xO4 hydroelectric cells (HECs), which serve as a promising avenue for environmentally friendly electricity generation. The MgGdxFe2-xO4 (x = 0.00, 0.02, 0.06 and 0.10) series for eco-friendly electricity generation has been successfully synthesized using a facile sol-gel technique. These materials exhibit the characteristic spinel cubic structure with the Fd-3 m space group confirmed using Rietveld analysis of X-ray diffraction plots. A maximum strain of 7.49×10-3 was observed in the MgGd0.10Fe1.90O4, indicating the formation of a probable defective structure. Moreover, the X-ray density values decrease with increase in Gd concentration, suggesting an increase in porosity of the samples. Langmuir hysteresis curve follows a typical type IV pattern further consolidating the mesoscopic nature of the materials. Furthermore, the conclusive identification of defects, particularly oxygen vacancies, through Photoluminescence and X-ray Photoelectron Spectroscopic (XPS) studies, holds an utmost importance in facilitating the water dissociation process at room temperature by ferrites. Impedance spectroscopy has been employed to scrutinize the contribution of small polaron hopping-assisted ionic conduction to the observed improved current density. The maximum short circuit output current of 6.8, 10.1, and 13.4 mA was achieved for MgGd0.02Fe1.98O4 (GMF-1), MgGd0.06Fe1.94O4 (GMF-2) and MgGd0.10Fe1.90O4 (GMF-3) HECs, respectively. The corresponding open cell voltage values were found to be 0.85 V, 0.92 V and 0.98 V. Off-load peak power output was 5.78 mW, 9.29 mW, and 13.13 mW, respectively. The estimated Gibbs free energy values were -164.02, -177.53, and −189.11 kJ/mol. MgGdxFe2-xO4-based hydroelectric cells possess the advantages of being cost-effective and yielding eco-friendly by-products without reliance on photocatalytic activity, acid/alkali solutions, or electrolytes. The incorporation of Gadolinium (Gd) dopant not only enhances the hydroelectric current but also contributes to sustained current generation over extended periods. The extended operational lifespan of the cell positions it as an excellent candidate for practical applications

Structural and dielectric properties of CaCu3Ti4O12 synthesized by sol–gel method

CaCu3Ti4O12 (CCTO) nanomaterials were synthesized using the low-cost facile sol-gel technique. X-ray diffraction (XRD) patterns confirmed the cubic structure of the prepared sample. Scherrer’s formula and the W-H (Williamson-Hall) plot was used to calculated the average crystallite size of the prepared sample and it was found to be 27 nm and 31.3 nm, respectively, while the strain created in the lattice is 5.008 × 10−4. Based on the absorbance plot, the band-gap (Eg ) of the sample was determined using Tauc’s plot and it was found out to be 2.74 eV. The frequency dependence of dielectric permittivity (ε) and tangent loss (tan δ) of CCTO was analyzed at different temperature range from 300 K to 663 K over a frequency range from 10 Hz to 1 MHz. ε and tan δ decrease monotonically in entire frequency range and an anomalous frequency-dependent behavior was observed at different temperatures. High ε (in the range of 104) was found out at lower frequency range. Electrical conductivity was also analyzed in range of frequencies and temperature, it was found out that in higher region of frequency conductivity slightly increases. The room temperature values of ε, tanδ and conductivity was 7.5 × 103, 1.5 and 0.4 × 10−5 Ω−1 m−1, respectively. The reduction in Eg is achieved which was the major concern in this work. Furthermore, we have extensively studied the ε along with tan δ and ac conductivity for electronic application usage. According to these observations, CCTO is particularly prepared so that it could be suitable for microelectronic applications due to its high ε and low tan δ.

Improving charge transfer properties and solar cell performance by In-doped TiO2 as an efficient photoanode for dye-sensitized solar cells (DSSCs)

Dye-sensitized-solar cells (DSSCs) are of great interest as cost-effective and green energy producers. The vastly explored photoanodes are one of the most significant parts of DSSC and still play a crucial role. We employed the fast and facile sol-gel technique to synthesize and dope TiO2 mesoporous structure with indium atoms. Although In doping in the TiO2 structure has been used previously, there have been few research on its application as photoanode in DSSCs. We investigated TiO2:In as an appropriate candidate for photoanode in DSSC and evaluated its charge transfer and optical, structural, and electrochemical properties. Mott-Schottky results show that indium doping can increase the carrier concentration up to 1.1 × 1017 cm−3 and elevate the conductivity as well as charge transfer properties. The optical and structural properties were investigated by PL, Raman, and UV–visible methods, and the results showed that TiO2:In has suppressed recombination in its structure. Also, In-doping improves the electrochemical properties of the photoanodes. The EIS results establish that In corporation can reduce the charge transfer resistance to 33 Ω cm2. The champion TiO2:In-based DSSC shows an 8.62 % efficiency, which indicates a 55 % improvement compared to the non-doped TiO2.

In situ fabrication of lanthanum-doped nickel oxide nanostructures using sol-gel for the degradation of rhodamine B.

Nanoscale science represents a thriving field of research for environmental applications within materials science. This study focuses on the fabrication of pure and La-doped nickel oxide (NiO) nanostructures with varying concentrations (1.0, 2.0, 3.0, and 4.0 wt%) of lanthanum using a facile sol-gel technique. This study explores the structural, morphological, chemical composition, and optical characteristics of the resulting pure and La-doped NiO nanostructures. Techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, UV-visible spectroscopy, and photoluminescence (PL) spectroscopy were used for material analysis. The observed trend in the energy band gap (Eg) values demonstrates a continuous decrease up to a La-doping concentration of 3 wt% in NiO. However, after this concentration (at 4.0 wt%), there is a noticeable increase in the energy band gap. At lower La-doping concentrations (up to 3 wt%), the incorporation of La ions into the NiO lattice may result in the formation of defects and oxygen vacancies. The presence of these imperfections may lead to new energy levels into the band gap, resulting in partial filling and a subsequent reduction in the band gap. Beyond a specific doping concentration (e.g., 3 wt%), excess La atoms may aggregate or cluster inside the NiO lattice. This agglomeration may cause structural distortions, strain, and disturbances in the crystal lattice, resulting in an increase in the band gap. The 3 wt% La-doped NiO sample demonstrated a notable 84% degradation efficiency of the synthesized nanomaterials coupled with its inherent stability, highlighting its dual attributes of effective pollutant removal and sustained performance. Furthermore, the cyclic stability of the optimized nanostructure is anticipated to be ∼77.42% after six cycles, suggesting promising future applications in photocatalysis.

Enhanced electrocatalytic degradation of acid orange 7 by using double perovskite La2CoxNi1-xMnO6/nickel foam as the electro-Fenton cathodes

Adequate generation of hydrogen peroxide and its subsequent activation into reactive oxygen species (ROS) play a crucial role in the catalytic efficiency of heterogeneous electro-Fenton for the degradation of contaminants. Herein, a series of La2NiMnO6 double perovskite with Co doping (La2CoxNi1-xMnO6) were prepared by a facile sol-gel technique and applied as catalysts in heterogeneous electro-Fenton system to removal acid orange 7 (AO7). Nickel foam was chosen as the supporting substrate for the catalyst owing to its excellent physical properties to accelerate the conversion of O2 to H2O2. La2Co0.5Ni0.5MnO6 achieved 90.22 % of AO7 decomposition rate at 120 min via the heterogeneous electro-Fenton system, which was a significant improvement over the catalytic efficiency of both only NF and La2NiMnO6 electrodes. Further studies have shown that the introduction of Co could heighten the efficient redox recycling of Ni2+/Ni3+ and Mn3+/Mn4+ on the electrode surface, synergically facilitating the conversion of H2O2 to OH. Meanwhile, the three redox pairs (Ni2+/Ni3+, Mn3+/Mn4+ and Co2+/Co3+) also stimulated the production of superoxide radicals (O2−), which was also not negligible in enhancing degradation. Finally, the possible pathway and mechanism of the degradation of AO7 were proposed. This work demonstrates that La2CoxNi1-xMnO6/NF has the potential to be a satisfactory electrode for decomposition of organic dyes in aqueous solution.

Plasmonic enhanced branched Ag sensitized Cu2O–CuO/TiO2 heterojunction with unprecedented photocatalytic degradation under visible light

A novel plasmonic Ag assisted Cu2O–CuO/TiO2 heterojunction photocatalyst was prepared using a facile sol-gel technique, and its MB degradation efficiency was explored. The physicochemical, morphostructural, and spectroscopic analyses using XRD, UV–vis-DRS, SEM, TEM, Raman, ESR, PL and XPS showed the formation of Ag@Cu2O–CuO/TiO2 hybrid photocatalyst, exhibiting surface plasmon resonance (SPR) and interfacial ternary heterojunctions. The SPR exhibited by the bulbous branched Ag nanostructures resulted in broad visible light absorption that extended into the near-infrared region. This plasmonic-heterojunction hybrid photocatalyst has shown excellent photocatalytic degradation, far surpassing the performance of its pristine counterparts under visible light illumination. The improved photocatalytic degradation of MB is attributable to the synergistic impact of reduced electron-hole pair recombination owing to Cu2O–CuO/TiO2 ternary junction, broad visible light absorption and near-field enhancement through the surface plasmon resonance effect. The current study demonstrates an integrated plasmonic-heterojunction photocatalytic system that offers a promising avenue for enhancing photocatalytic performance in dye-contaminated water treatment.

Facile synthesis of reusable Ag/TiO2 composites for efficient removal of antibiotic oxytetracycline under UV and solar light irradiation

BackgroundsIn this work, Ag-doped TiO2 nanomaterials (TiAgx, where x denotes the weight percentage of Ag) were prepared using a facile one-step sol-gel technique. The combination of Ag with TiO2 promises to enhance the lifetime of photogenerated electron-hole pairs and widen the photocatalytic activity in the visible light region, leading to improved photocatalytic activity. MethodsThe synthesized materials were characterized using different analyses and afterwards applied as photocatalysts to degrade oxytetracycline (OTC) in aqueous solution under ultraviolet (UV) and solar light illumination. Significant findingsThe highest photocatalysis was achieved for TiAg2 with 99.6% OTC removal after 120-min UV irradiation. Moreover, the best OTC removal under solar light irradiation was gotten for TiAg5, of which 94.1% of OTC was removed after 180 min. Reactive species of ∙O2− radicals were presented as the dominant agents in OTC oxidization; meanwhile, ∙OH and h+ contributed to the photodegradation process. The mineralization efficiency of OTC using TiAg2 reached 59.6% after 240-min UV irradiation. Furthermore, the OTC removal of TiAg2 by photocatalysis still maintained over 97% after 5 cycles.

“An insight into the microstructural properties and dielectric behavior of Ce doped WO3 nanoparticles”

W1-xCexO3 (0.0≤x≤0.08) nanoparticles were successfully synthesized via surfactant assisted facile sol-gel technique. Influence of dopant ion on microstructural properties, dielectric response, ac conductivity, impedance, and electric modulus of WO3 nanoparticles have been studied. The particle morphology was affected upon Ce insertion from irregular to spherical to flakes as revealed by TEM images. XRD backed by Rietveld refinement confirmed monoclinic phase of all samples without any impurity. The microstructural properties like stress, strain and energy density have been determined using different W–H methods (UDM, UDSM, UDEDM). The FTIR spectra illustrated the presence of characteristic m-WO3 absorption bands centered at 612, 769 and 822 cm−1. The dielectric properties found to be significantly tuned with Ce doping and ac conductivity follows the Jonscher power law where the value of ‘s’ lies below unity. The Cole-Cole plots and electrical modulus analysis suggested the non-Debye type relaxation mechanisms.

Sol-gel based synthesis to explore structure, magnetic and optical properties of double perovskite Y2FeCrO6 nanoparticles

In this present investigation, nanoparticles of B-site disordered Y2FeCrO6 (YFCO) double perovskite have been successfully synthesized for the first time by optimizing synthesis steps and temperatures of facile sol-gel technique to investigate their structural, magnetic, and optical properties. The Rietveld refinement of the X-ray diffraction pattern of YFCO nanoparticles revealed a single-phase orthorhombic structure with pbnm space group. The average size of the nanoparticles is around 67±15 nm determined by both field emission scanning electron microscopy and transmission electron microscopy imaging. The existence of mixed valence states of Fe and Cr ions was confirmed by X-ray photoelectron spectroscopy which is an indication of the absence of proper B site long range ordering. The temperature dependent magnetization curves demonstrated negative magnetization of this double perovskite material with compensation temperature at around 170 K. The field-dependent magnetic hysteresis loops exhibited the coexistence of weak ferromagnetic and antiferromagnetic domains in YFCO nanoparticles. The exchange bias effect was observed below Néel temperature which is tunable by a cooling magnetic field. The UV–visible spectroscopy ensured that YFCO nanoparticles have a direct band gap of ∼ 1.90 eV, which was further confirmed by steady-state photoluminescence spectroscopy. This B-site disordered YFCO might enhance interest on basic fundamental research on disordered rare-earth and transition metal-based perovskite systems and can be used for spintronics as well as photocatalytic applications because of its favorable magnetic and optical properties.

A facile sol–gel synthesis and characterization of europium (Eu) doped β-Bi2Mo2O9 nanoparticles with remarkably enhanced photocatalytic activity for waste-water treatments

• The pure and Eu doped β-Bi 2 Mo 2 O 9 nanoparticles were synthesised via sol gel method using acid medium and water medium. • Single phase β - Bi 2 Mo 2 O 9 formation and porous natured self-assembly was confirmed with XRD, SEM and Raman. • Eu doped Bi 2 Mo 2 O 9 shows enhanced photocatalytic activity thereby degrading the Methylene blue completely when compared to pure sample. A facile sol-gel technique was employed to synthesize the nanoparticles of β-Bi 2 Mo 2 O 9 in acidic and water medium and Eu doped β-Bi 2 Mo 2 O 9 in acidic medium. The crystalline structure of the synthesized nanoparticles was characterized by powder X-ray Diffractometry, thereby confirming the monoclinic structure of pure β-Bi 2 Mo 2 O 9 and Eu-doped β-Bi 2 Mo 2 O 9 . Raman analysis was performed to verify the phase purity and to identify the vibrational modes of synthesized pure and doped molybdates. The surface morphology of synthesized particles was examined using scanning electron microscopy, which shows the formation of a honeycomb-like structure with numerous pores. UV-visible spectroscopy and XPS studied the optical properties of synthesized nanoparticles. The dye degradation process demonstrated the photocatalytic activity under visible light radiation in which Methylene blue acts as a model dye. The change in the absorbance of the dye with synthesized β-Bi 2 Mo 2 O 9 and Eu-doped β-Bi 2 Mo 2 O 9 with different concentrations of Eu 3+ was studied by a UV-Visible spectrophotometer. The results indicate that the water-based β-Bi 2 Mo 2 O 9 shows more dye degradation than acidic-based β-Bi 2 Mo 2 O 9 . The doping of Eu3+ increased the photocatalytic activity of acidic-based β-Bi 2 Mo 2 O 9 synthesis, and the efficiency increased with an increase in the doping percentage of Eu 3+ . The 10% Eu:Bi 2 Mo 2 O 9 completely degraded the Methylene Blue dye (100%) within a period of 4hours.

Investigating the structural, optical, and photocatalytic activity of TiO2/SnO2 nanocomposites synthesized by the facile sol-gel technique for dye degradation

The photocatalytic degradation of dyes using semiconducting metal oxides has received a lot of interest recently. In this work, TiO2, SnO2, and TiO2/SnO2 nanocomposites with different SnO2 contents were synthesized via the facile and cost-effective sol-gel method and fully characterized. X-ray diffraction (XRD) pattern analysis indicated that the crystallite size reduced remarkably and the transformation of anatase to rutile phase accelerated significantly with increasing the SnO2 content. Raman spectroscopy confirmed the XRD results. Electron microscope images revealed that the TiO2/SnO2 composites have composed of semi-spherical fused particles, where increasing the SnO2 content causes the reduction of the particles’ size. The addition of SnO2 caused the photoluminescence (PL) intensity reduction due to the easy migration of photoelectrons from the TiO2 to the SnO2 conduction band, leading to a decrease in the recombination of photogenerated electron-hole pairs. Catalytic activity was tested by methylene blue under 360 nm ultraviolet (UV) irradiation. Intrinsic TiO2 showed better photocatalytic activity than pure SnO2, but the color degradation was still less than 50% after 90 min. UV irradiation. Increasing the SnO2 content in the TiO2 produced nanocomposites with higher color degradation rates of about 73% after 90 min. UV irradiation, suggesting the binary metal oxide TiO2/SnO2 nanocomposite photocatalyst as a promising candidate for effluent dye removal.

Vanadium-doped CuO: Insight into structural, optical, electrical, terahertz, and full-spectrum photocatalytic properties

Aiming to widen the band gap, minimize the charge-carrier recombination, and enhance the transport properties, we reported the first synthesis of high purity vanadium-doped CuO as a promising photocatalyst nanopowder for water purification. Pure CuO and Cu1-xVxO (where x = 0.00, 0.01, 0.03, 0.05, and 0.07 mol) were synthesized by a facile sol-gel technique. The structural investigation performed by both X-ray and selected area electron diffraction patterns evidenced the formation of highly pure monoclinic CuO. The vanadium inclusion caused a noticeable red shift in Bragg's positions. The grain size was estimated by both Debye-Scherrer and Halder-Wagner methods and ranged from 21 to 28 nm. All the vibrational absorption bands disclosed by FTIR measurement are affiliated with monoclinic CuO exhibiting a small shift for V-doped nanopowders. The stoichiometry of the constituent elements (Cu, O, and V) was assured by energy dispersive X-ray analysis (EDX). The presence of agglomeration is the main feature in field emission scanning electron microscope images revealing the nanostructure property of CuO. The band gap energy of Cu0.93V0.07O determined from diffuse reflectance is 1.44 eV which meets exactly the peak of the solar spectrum rendering it a promisingly photocatalytic material. The rise of absorption in the terahertz range as measured by THz time-domain spectroscopy (THz-TDS) established the increase of density of states owing to the inclusion of vanadium. The incorporation of 0.07 mol of V considerably increases the free sunlight photocatalytic activity of CuO for high concentration Congo red pollutant (20 ppm) from 30 to 76% at the same time of 100 min (over 1.53 times as pure CuO)

Beneficial effect of Sn doping on bismuth ferrite nanoparticle-based sensor for enhanced and highly selective detection of trace formaldehyde

Pure and sn-doped bismuth ferrite (BFO) nanoparticles were synthesized via facile sol–gel technique. Structural and morphological analysis of the nanoparticles were systematically carried out by using X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy and Brunauer–Emmett–Teller techniques. The gas sensing properties of the sensors based on prepared nanoparticles towards formaldehyde in the temperature range from 200 °C to 400 °C revealed that the doping of Sn enhances the formaldehyde sensing performance of BFO nanoparticle by few folds. Prepared sensors demonstrate p-type behaviour and high selectivity towards formaldehyde. It was observed that the sensor based on 1.5 % Sn doped BFO nanoparticles exhibited maximum sensing response of 3.05 (Rg/Ra) to 1 ppm formaldehyde. Prepared sensors were ultra-fast (response/recovery time of 2.71 s/25.22 s) and very stable having low detection limit of 100 ppb. The enhancement of formaldehyde sensing property due to sn-doping is a combined effect of variation of charge carriers due to valency mismatch and enhanced oxygen defects as confirmed from X-ray photoelectron spectroscopy study. sn-doped BFO nanoparticles could be a potential candidate for the detection of trace formaldehyde gas towards the monitoring of both indoor and outdoor environmental air quality.

Study on the role of rGO in enhancing the electrochromic performance of WO3 film

In the present work, an improved electrochromic thin film has been developed with faster color switching time on incorporation of rGO in WO3 film. Here, pristine WO3 and rGO-WO3 (rGO concentration varying from 1–7wt%) based nanocomposite electrochromic films were fabricated on ITO coated glass substrate, by utilizing a facile sol-gel dip-coating technique. Detailed structural and morphological analyses of the films were carried out using XRD, FESEM, TEM and Raman Spectroscopy. Assimilating the electrochromic properties of all the films showed that, 5wt% rGO incorporated WO3 film gave a maximized electrochemical performance with minimum degradation in optical transmittance. The film also exhibited an optical modulation of ∼ 50% and a better switching response having coloration time (tc) ~ 5.3 s and bleaching time (tb) ~ 6.2 s as compared to the pristine film (tc~ 9.6 s, tb ~ 10.4 s). Incorporation of rGO also resulted in an enhancement of coloration efficiency from ∼ 81 to ∼ 386 cm2/C. The Electrochemical Impedance Spectroscopy (EIS) analysis of pristine and rGO loaded film clearly revealed better charge transfer on incorporation of rGO. The cyclic stability study exhibited ∼ 25% deterioration in optical transparency of the bare WO3 film which was < 10% for the rGO impregnated film. An ex-situ XRD analysis demonstrated that a crystal dislocation occurring in pristine WO3 sample was responsible for the same.

Sol-gel synthesis of nanostructured ZnO/SrZnO2 with boosted antibacterial and photocatalytic activity

Due to extensive industrialization, toxic dyes and pathogenic microbes are contaminating water supplies at an alarming rate. This situation is alarming for humans and all other living organisms that directly or indirectly depend upon water. Photocatalysis is the best technique for eliminating harmful dyes and pathogenic microbes from drinking water since it is cost-effective and ecologically acceptable. To improve the effectiveness of the photocatalysis technique, materials researchers must develop an ideal photocatalyst with a narrow-bandgap, a broad absorption range, and efficient charge separation. Here, we adopted a facile sol-gel technique to synthesize a nanostructured ZnO/SrZnO 2 composite that acts as an efficient visible light-triggered photocatalyst. The prepared photocatalyst mineralized the azo dye (Congo red, CR) and destroyed the bacterial strain ( Escherichia Coli, E-Coli ) under visible-light-irradiation. The photocatalytic test findings revealed that the as-prepared ZnO/SrZnO 2 composite exhibited a higher photocatalytic efficiency of mineralizing 92.4% of the CR dye as compared to SrZnO 2 (57.9%) and ZnO (34.6%). Kinetic analysis revealed that the CR dye degradation rate over ZnO/SrZnO 2 nanocomposite was 5.6 times faster than pure ZnO while 2.5 times faster than SrZnO 2 . Scavenger's experiments proposed that the peroxide free-radical play a key role, while the positively charged holes play a minor role in the mineralization of CR dye. Additionally, the ZnO/SrZnO 2 composite also shows better antibacterial action, as it kills E.coli more effectively by interfering with its essential cellular activities/functions. The photocatalytic and antibacterial properties of our manufactured ZnO/SrZnO 2 nanocomposite indicate that it has significant potential to mineralize the poisonous dyes and kill pathogenic microbes.

Dual-shell silicate and alumina coating for long lasting and high capacity lithium ion batteries

Here we demonstrate a theory-driven, novel dual-shell coating system of Li2SrSiO4 and Al2O3, achieved via a facile and scalable sol-gel technique on LiCoO2 electrode particles. The optimal thickness of each coating can lead to increased specific capacity (∼185 mAh/g at 0.5C-rate) at a cut-off potential of 4.5 V, and greater cycling stability at very high C rates (up to 10C) in half-cells with lithium metal. The mechanism of this superior performance was investigated using a combination of X-ray and electron characterization methods. It shows that the results of this investigation can inform future studies to identify still better dual-shell coating schemes, achieved by such industrially feasible techniques, for application on similar, nickel-rich cathode materials.

Large temperature coefficient of resistivity (TCR) of La1-xCaxMnO3 films prepared by spin-coating method

La1-xAxMnO3 (A = alkaline-earth or alkali metal) perovskites with large temperature coefficient of resistivity (TCR) offer immense opportunity for the application in high-performance infrared bolometer. However, numerous studies have revealed that the manganite films with large TCR values are not easily obtained by various fabrication technologies. Herein, a facile sol-gel spin-coating technique was used to prepare La1-xCaxMnO3 (LCMO, 0.280 ≤ x ≤ 0.375) films. All the samples were highly oriented along the out-of-plane direction of La0.3Sr0.7Al0.65Ta0.35O3 (001) substrates. With the rise in Ca doping amount, the resistivity of the films first decreased, and then, increased. This change can be attributed to the competition between the carrier concentration and lattice distortion. The LCMO films displayed large TCR and low-field magnetoresistance (MR) values, which exceeded those of previously reported thin films. The maximum TCR and low-field MR values were observed at x = 0.330, reaching 30.13% K−1 (266.43 K) and 68.6% (270.08 K), respectively. The La0.67Ca0.33MnO3 film with large TCR and MR values presents potential for the applications in high-sensitivity infrared bolometers and magnetic sensors.