Synthesized PANI/CeO2 Nanocomposite Films for Enhanced Anti-Corrosion Performance.

This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm-1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm-1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.

Enhanced Electrocatalytic Oxygen Reduction Reaction of TiO2 Nanotubes by Combining Surface Oxygen Vacancy Engineering and Zr Doping.

This work examines the cooperative effect between Zr doping and oxygen vacancy engineering in anodized TiO2 nanotubes (TNTs) for enhanced oxygen reduction reactions (ORRs). Zr dopant and annealing conditions significantly affected the electrocatalytic characteristics of grown TNTs. Zr doping results in Zr4+ substituted for Ti4+ species, which indirectly creates oxygen vacancy donors that enhance charge transfer kinetics and reduce carrier recombination in TNT bulk. Moreover, oxygen vacancies promote the creation of unsaturated Ti3+(Zr3+) sites at the surface, which also boosts the ORR interfacial process. Annealing at reductive atmospheres (e.g., H2, vacuum) resulted in a larger increase in oxygen vacancies, which greatly enhanced the ORR activity. In comparison to bare TNTs, Zr doping and vacuum treatment (Zr:TNT-Vac) significantly improved the conductivity and activity of ORRs in alkaline media. The finding also provides selective hydrogen peroxide production by the electrochemical reduction of oxygen.

Chitosan magnetic graphene grafted polyaniline doped with cobalt oxide for removal of Arsenic(V) from water.

The present study reports the successful functionalization/magnetization of bio-polymer to produce chitosan-magnetic graphene oxide grafted polyaniline doped with cobalt oxide (ChMGOP-Co3O4). Analytical techniques furrier transform infra-red (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the formation of ChMGOP-Co3O4. The effects of several experimental factors (solution pH, adsorbent dosage and coexisting ions) on the uptake of As(V) ions using ChMGOP-Co3O4 were examined through batch experiments. As(V) removal process was validated by experimentally and theoretically investigating the adsorption capacity, rate, and thermal effects. Thermodynamic parameters such as free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) were also calculated and were used to explain the mechanism of adsorption. Based on the results, the sorbent showed a high adsorption capacities (90.91 mg/g) at favorable neutral pH and superior removal efficiencies as high as 89% within 50 min. In addition, the adsorption isotherm followed the Langmuir isotherm in compare to the Freundlich, due to its higher R2 value (0.992 < 0.941). Meanwhile, the kinetic data revealed that the of As(V) adsorption was controlled by pseudo-second-order. Overall, the adsorption mechanism studies revealed a spontaneous endothermic nature with predominance of physisorption over chemisorption. This study indicated that ChMGOP-Co3O4 is an exceptional novel adsorbent material for the efficient isolation of As(V) from aqueous media.

TD-DFT Simulation and Experimental Studies of a Mirrorless Lasing of Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)].

In this work, we investigate the TD-DFT simulation, optical, and mirrorless laser properties of conjugated polymer (CP) Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], also known as (PFO-co-PPV-MEHB) or ADS125GE. TD-DFT calculations were performed for three monomer units with truncated tails using time-dependent density functional theory (TD-DFT) calculations. The calculations showed a highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) structure and a very high oscillator strength of 6.434 for the singlet-singlet transition at 374.43 nm. Experimentally, the absorption and fluorescence spectra were examined at various concentrations in verity of solvents, such as benzene, toluene, and hexane. The experimental results obtained in hexane were comparable with theoretical UV-VIS spectra calculated under vacuum. Amplified spontaneous emission (ASE) spectra peaked at approximately 509 nm for CO PFO-co-PPV-MEHB in solution and were obtained at suitable concentrations and pump energies. Additionally, the photochemical stability of this CP and coumarin (C510) were compared. Time-resolved spectroscopy (TRS) studies with a sub-nanosecond resolution were performed for the CO under various pump energies. These results showed the excited state dynamics and single-pass optical gain of CO PFO-co-PPV-MEHB.

Metagenomic analysis of microbial community and its role in bioelectrokinetic remediation of tannery contaminated soil.

Tanneries create a serious threat to the environment by generating a significant amount of toxic metal-containing solid waste. This study deals with the application of bio-electrokinetic remediation (Bio-EK) of tannery effluent contaminated soil (TECS). Metagenomes representing the TECS sample were sequenced using the Illumina HiSeq platform. The bioreduction of hexavalent chromium Cr(VI)to trivalent chromium Cr (III) was achieved by BIO-EK techniques. NGS-data (Next Generation Sequencing) analysis was revealed that Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Planctomycetes were identified in the bio-electrokinetic system. Proteobacteria are responsible for the bioreduction of chromium hexavalent by the formation of FeS particles. The bio-generated FeS particles can be reduced the toxic chromium (VI) to non-toxic chromium (III) in soil. Simultaneously total chromium and organic content were significantly removed in BIO-EK (40 and 290 mg kg-1) when compared to control soil (182 and 240 mg kg-1). The presence of pollutant degrading microbes such as Desulfovibrio, Pseudomonas, Bacillus, Clostridium, Halanaerobium enhanced the bioreduction of the chromium during the electrokinetic remediation. This study can be claimed that the microbial cultures assisted electrokinetic remediation of total chromium, organic and iron in the tannery effluent contaminated soil was one of the suitable efficient techniques. In addition, the viability of the new combination technology developed (Electrokinetic + Bio) to treat low-permeability polluted soils was demonstrated.

A straightforward synthesis of visible light driven BiFeO3/AgVO3 nanocomposites with improved photocatalytic activity.

Herein, an efficient visible-light-driven BiFeO3/AgVO3 nanocomposite was effectively fabricated via a facile co-precipitation procedure. The physicochemical properties of BiFeO3/AgVO3 nanocomposites were investigated via Fourier transform-infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), UV visible diffuse reflectance spectroscopy (DRS) and photoelectrochemical studies (PEC). The photocatalytic activity (PCA) of BiFeO3/AgVO3 nanocomposites was assessed with regard to the photocatalytic degradation of Rhodamine-B (RhB) when subjected to visible light irradiation (VLI). Upon 90 min of illumination, the optimal 3%-BiFeO3/AgVO3 nanocomposite showed a greater photocatalytic degradation, which was ∼3 times higher than the bare AgVO3. The lower PL intensity of 3%-BiFeO3/AgVO3 nanocomposite exposed the low recombination rate, which improved the photo-excited charge carriers separation efficiency. The experimental outcomes showed that the BiFeO3/AgVO3 nanocomposite might be an encouraging material for treatment of industrial and metropolitan wastewater. Moreover, a plausible RhB degradation mechanism was proposed proving the participation of the generated OH and O2- radicals in the degradation over BiFeO3/AgVO3 nanocomposite.

Biological mediated synthesis of RGO-ZnO composites with enhanced photocatalytic and antibacterial activity.

In this study, we reported the biological approach to synthesis of ZnO nanorod (NR) on the reduced graphene oxide (RGO) for photocatalytic, antibacterial activity and hydrogen production under sunlight. Bacillus subtilis played a vital role in the production of biogenic ammonia from synthetic urine and utilized for the synthesis of ZnONR on the RGO sheet. The morphological study revealed that RGO sheets displayed a tremendous role in anchoring ZnONR. XRD patterns showed the ZnO crystal phase on the RGO sheets. XPS and Raman spectra confirmed that the bio-hydrothermal method as suitable for GO converted into RGO. The transient photocurrent and I/V measurement are exhibited as an increment on the RGO-ZnONR compared to ZnONR. The RGO-ZnONR composites showed excellent performance with decolorization of MB and textile dyes and efficient control of the E. coli and S. aureus. RGO-ZnONR exhibited remarkable noted as a higher photocatalytic hydrogen evolution rate (940 µmol/h/gcat) than the ZnONR (369.5 µmol/h/g cat). As a result of photocatalytic performance to correlate with sunlight intensity was extensively studied. RGO plays an essential role in interface electron transfer from sunlight to ZnONR for enhancing •OH radical formation to cleavage of dye color substance and eradicated bacterial cells.

Time-resolved spectroscopy of radiative energy transfer between a conjugated oligomer and polymer in solution.

We report a short investigation of the energy transfer process between the conjugated oligomer 1,4-bis(9-ethyl-3-carbazo-vinylene)-9,9-dihexyl-fluorene (BECV-DHF) and the conjugated polymer poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene-vinylene] - end capped with DMP (MDMO-PPV). The radiative energy transfer (RET) process shows a time delay, and the formation of the excimer causes a further delay. All these processes were studied using time-resolved spectroscopy (TRS), which has three-dimensional (3D) features with wavelength, intensity and time (picosecond) as the X, Y and Z-axis, respectively. We observed a definitive delay (1 ns) in the fluorescence from MEDMO-PPV concerning the fluorescence of the oligomer, indicating the RET. The TRS of different relative concentrations and temperature effects on the energy transfer process was also studied. The quantum yield, critical distance, polarizability and change of MEDMO-PPV were calculated. The excimer of the MEDMO-PPV produces Amplified Spontaneous Emission (ASE) after a time delay of at least 0.5 ns, which was also observed in this study.

Narrowband Spontaneous Emission Amplification from a Conjugated Oligomer Thin Film.

In this paper, we studied the laser and optical properties of conjugated oligomer (CO) 1,4-bis(9-ethyl-3-carbazo-vinylene)-9,9-dihexyl-fluorene (BECV-DHF) thin films, which were cast onto a quartz substrate using a spin coating technique. BECV-DHF was dissolved in chloroform at different concentrations to produce thin films with various thicknesses. The obtained results from the absorption spectrum revealed one sharp peak at 403 nm and two broads at 375 and 428 nm. The photoluminescence (PL) spectra were recorded for different thin films made from different concentrations of the oligomer solution. The threshold, laser-induced fluorescence (LIF), and amplified spontaneous emission (ASE) properties of the CO BECV-DHF thin films were studied in detail. The ASE spectrum was achieved at approximately 482.5 nm at a suitable concentration and sufficient pump energy. The time-resolved spectroscopy of the BECV-DHF films was demonstrated at different pump energies.

Antimicrobial and catalytic activities of biosynthesized gold, silver and palladium nanoparticles from Solanum nigurum leaves.

The field of nanobiotechnology and nanomedicine paves way for the use of several nanoparticles. Especially, in biomedical applications, the silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and palladium nanoparticles (PdNPs) are found most vital and promising, among other nanoparticles. The biomedical activities of these particles mostly depend on their shape, size and distribution. Preparation of these particles in an eco-friendly method is an immediate need of the society. Herein, AuNPs, AgNPs and PdNPs (MNPS) were synthesized by Solanum nigrum Leaves (SNL) extract. The structural and morphological studies were carried out by using TEM, XRD and EDAX, while the optical and chemical properties were studied using UV-visible spectrum and FTIR spectroscopy. The particles obtained were found to possess a FCC (Face Centered Cubic) structure. TEM images of Ag, Au and PdNPs showed spherical well dispersed nanoparticles with average size of 3.46 nm, 9.39 nm and 21.55 nm respectively. The FTIR spectra confirmed polyphenols and antioxidants in SNL extract act as reducing and capping agents respectively in the synthesis of MNPs. The EDX technique confirmed the presence of silver, gold and palladium nanoparticles. Antimicrobial studies noted that the AgNPs have effective inhibition against E. coli. The complete reduction of 4-Nitrophenol and the formation of 4-Aminophenol with the presence of NaBH4 was chosen for the study of catalytic activities of the prepared MNPs. The reduction time of Au and Pd catalyst were smaller compared to that of Ag. This viable preparation method for producing small spherical shaped nanoparticles expected to the applied to the fields of nanomedicine.

Optically Pumped Intensive Light Amplification from a Blue Oligomer.

We demonstrated the time-resolved dynamics of laser action from the conductive oligomer (CO) 1,4-Bis(9-ethyl-3-carbazo-vinylene)-9,9-dihexyl-fluorene (BECV-DHF). Absorption and fluorescence spectra were studied for BECV-DHF in different solvents under a wide range of concentrations. The Fourier-transform infrared spectroscopy (FTIR) spectrum was measured using simulation and experiments. The Ultraviolet-Visible (UV-VIS) spectra of the BECV-DHF were simulated in two different solutions. This CO formed a dimer and had two vibration bands in nonpolar solvents, partially dissolved in polar protic solvents, and created an H-type aggregate in polar aprotic solvents. BECV-DHF produced amplified spontaneous emission (ASE) at 464 nm in many solvents. The high efficiency of ASE is due to the waveguiding and self-assembly nature of the oligomer, which is very rare for optically pumped systems. However, BECV-DHF did not produce ASE in polar protic solvents. BECV-DHF produced ASE in both longitudinal and transverse pumping, and the full-width half maximum (FWHM) was 4 nm and 8 nm respectively for different solvents, such as toluene and acetone. The CO had a very low threshold pump energy (~0.5 mJ). The ASE efficiency was approximately 20%. The time-resolved spectroscopy (TRS) studies showed a temporal Gaussian-shaped ASE output from this CO. BECV-DHF shows remarkably high stability compare to the conjugated polymer (CP) PFO-co-pX.

A Temperature-Tunable Thiophene Polymer Laser.

This paper reports a temperature-tunable conjugated polymer poly[3-(2-ethyl-isocyanato-octadecanyl)-thiophene] (TCP) laser working in superradiant (SR)-or amplified spontaneous emission (ASE)-mode. The absorption spectra indicated the aggregate (mostly dimer) formation upon increasing concentration and/or decreasing temperature. Amplified spontaneous emission (ASE) was observed at suitable concentration, temperature, and pump energy values. The efficiency of the ASE from the TCP polymer was improved by energy transfer from an oligomer 9,9,9',9',9″,9″-hexakis(octyl)-2,7',2',7″-trifluorene (HOTF). Moreover, the ASE wavelength can be tuned between 550 and 610 nm by changing the temperature of the solution from 60 to 10 °C. To the best of our knowledge, this is the first report of a high-power, temperature-tunable, and conjugated polymer laser.