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.

Enhanced electrocatalytic oxygen redox reactions of iron oxide nanorod films by combining oxygen vacancy formation and cobalt doping

A synergistic effect of Co-doping and vacuum-annealing on electrochemical redox reactions of iron oxide films is demonstrated in the present work. In this research, a series of defect-rich iron oxy/hydroxide nanorod arrays: α-FeOOH, Fe2O3, and FeOx nanorod thin film catalysts were synthesized via a hydrothermal approach followed by thermal and vacuum treatments. Besides, a cobalt doping process was employed to prepare the thin film of Co-doped FeOx nanorods. The morphology, crystallinity, and electrochemical activities of Co-doped oxygen-deficient FeOx (Co-FeOx/FTO) show strong correlations with metal concentration and thermal treatments. The electrochemical measurements demonstrated that the as-deposited Co-doped FeOx NR catalyst could achieve a maximum OER current of 30 mA cm-2, which was six times greater than that recorded by as-deposited Co-doped FeOOH NR catalysts (5.7 mA cm-2) at 1.65 V vs. RHE, confirming the superior electrocatalytic OER activity at the as-deposited Co-doped FeOx NR catalyst after cobalt doping. It is believed that these results are attributed to two factors: the synergistic effect of Co doping and the defect-rich nature of FeOx nanorod catalysts that are used in sustainable energy systems.

Bifunctional vanadium doped mesoporous Co3O4 on nickel foam towards highly efficient overall urea and water splitting in the alkaline electrolyte

Developing more active and stable electrode materials for oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is necessary for electrocatalytic water and urea oxidation which can be used to generate hydrogen. Here, a low-cost vanadium-doped mesoporous cobalt oxide on Ni foam (V/meso-Co/NF) electrodes are obtained via the grouping of an in-situ citric acid (CA)-assisted evaporation-induced self-assembly (EISA) method and electrophoretic deposition process, and work as highly efficient and long-lasting electrocatalytic materials for OER/UOR. In particular, V/meso-Co/NF electrodes require 329 mV overpotential to maintain a 50 mA/cm2, with exceptional long-term durability of 30 h. Interestingly, V/meso-Co/NF also exhibits excellent electrocatalytic UOR performance, reaching 50 and 100 mA/cm2 versus RHE at low potentials of 1.34 and 1.35 V, respectively. By employing the V/meso-Co/NF materials as both the anode and cathode, this urea electrolysis assembly V/meso-Co/NF-5 (+,-) reaches current densities of 100 mA cm-2 at 1.62 V in KOH/urea, which is nearly 340 mV lesser than classical water electrolysis. The V/meso-Co/NF-5 electrocatalysts also exhibit remarkable durability for electrocatalytic OERs and UORs. The obtained findings revealed that the synthesized V/meso-Co/NF might be a promising electrode materials for overall urea-rich wastewater management and H2 generation from wastewater.

Photoelectrochemical Performance of Strontium Titanium Oxynitride Photo-Activated with Cobalt Phosphate Nanoparticles for Oxidation of Alkaline Water

Photoelectrochemical (PEC) solar water splitting is favourable for transforming solar energy into sustainable hydrogen fuel using semiconductor electrodes. Perovskite-type oxynitrides are attractive photocatalysts for this application due to their visible light absorption features and stability. Herein, strontium titanium oxynitride (STON) containing anion vacancies of SrTi(O,N)_3-δ was prepared via solid phase synthesis and assembled as a photoelectrode by electrophoretic deposition, and their morphological and optical properties and PEC performance for alkaline water oxidation are investigated. Further, cobalt-phosphate (CoPi)-based co-catalyst was photo-deposited over the surface of the STON electrode to boost the PEC efficiency. A photocurrent density of ~138 μA/cm at 1.25 V versus RHE was achieved for CoPi/STON electrodes in presence of a sulfite hole scavenger which is approximately a four-fold enhancement compared to the pristine electrode. The observed PEC enrichment is mainly due to the improved kinetics of oxygen evolution because of the CoPi co-catalyst and the reduced surface recombination of the photogenerated carriers. Moreover, the CoPi modification over perovskite-type oxynitrides provides a new dimension for developing efficient and highly stable photoanodes in solar-assisted water-splitting reactions.

Detection of Structure Characteristics and Its Discontinuity Based Field Programmable Gate Array Processor in Cancer Cell by Wavelet Transform

Digital clinical histopathology is one of the crucial techniques for precise cancer cell diagnosing in modern medicine. The Synovial Sarcoma (SS) cancer cell patterns seem to be a spindle shaped cell (SSC) structure and it is very difficult to identify the exact oval shaped cell structure through pathologist’s eye perception. Meanwhile, there is necessitating for monitoring and securing the successful and effective image data processing in the the huge network data which is also a complex one. A field programmable Gate Array (FPGA) was regarded as a necessary one for this. In this work, based on FPGA a Cancer Cell classification is made for the regulation and execution. Hence, mathematically the SSC regularity structures and its discontinuities are measured by the holder exponent (HE) function. In this research work, HE values have been determined by Wavelet Transform Modulus Maxima (WTMM) and Wavelet Leader (WL) methods with basis function of Haar wavelet based on FPGA Processor. The quantitative parameters such as Mean of Asymptotic Discontinuity (MAD), Mean of Removable Discontinuity (MRD) and Number of Discontinuity Points (NDPs) have been considered to determine the prediction of discontinuity detection between WTMM and WL methods. With the help of receiver operating characteristics (ROC) curve, the significant difference of discontinuity detection performance between both the methods has been analyzed. From the experimental results, it is clear that the WL method is more practically feasible and it gives satisfactory performance, in terms of sensitivity and specificity percentage values, which are 80.56% and 59.46%, respectively in the blue color components of the SNR 20 dB noise image.

Nanofiber NiMoO4/g-C3N4 Composite Electrode Materials for Redox Supercapacitor Applications

NiMoO₄/g-C₃N₄ was fabricated by a hydrothermal method and used as an electrode material in a supercapacitor. The samples were characterized by XRD, FTIR, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study the physical and structural properties of the as-prepared NiMoO₄/g-C₃N₄ material. The electrochemical responses of pristine NiMoO₄ and the NiMoO₄/g-C₃N₄ nanocomposite material were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). From the CD studies, the NiMoO₄/g-C₃N₄ nanocomposite revealed a higher maximum specific capacitance (510 Fg⁻¹) in comparison to pristine NiMoO₄ (203 Fg⁻¹). In addition, the NiMoO₄/g-C₃N₄ composite electrode material exhibited high stability, which maintained up to 91.8% capacity even after 2000 charge-discharge cycles. Finally, NiMoO₄/g-C₃N₄ was found to exhibit an energy density value of 11.3 Whkg⁻¹. These findings clearly suggested that NiMoO₄/g-C₃N₄ could be a suitable electrode material for electrochemical capacitors.

Mesoporous Tungsten Trioxide Photoanodes Modified with Nitrogen-Doped Carbon Quantum Dots for Enhanced Oxygen Evolution Photo-Reaction

Nanostructured photoanodes are attractive materials for hydrogen production via water photo-electrolysis process. This study focused on the incorporation of carbon quantum dots doped with nitrogen as a photosensitizer into mesoporous tungsten trioxide photoanodes (N-CQD/meso-WO₃) using a surfactant self-assembly template approach. The crystal structure, composition, and morphology of pure and N-CQD- modified mesoporous WO₃ photoanodes were investigated using scanning electron and transmission microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Due to their high surface area, enhanced optical absorption, and charge-carrier separation and transfer, the resulting N-CQD/meso-WO₃ photoanodes exhibited a significantly enhanced photocurrent density of 1.45 mA cm^-2 at 1.23 V vs. RHE under AM 1.5 G illumination in 0.5 M Na₂SO₄ without any co-catalysts or sacrificial reagent, which was about 2.23 times greater than its corresponding pure meso-WO₃. Moreover, the oxygen evolution onset potential of the N-CQD/meso-WO₃ photoanodes exhibited a negative shift of 95 mV, signifying that both the charge-carrier separation and transfer processes were promoted.

A review on ZnO nanostructured materials: energy, environmental and biological applications

Zinc oxide (ZnO) is an adaptable material that has distinctive properties, such as high-sensitivity, large specific area, non-toxicity, good compatibility and a high isoelectric point, which favours it to be considered with a few exceptions. It is the most desirable group of nanostructure as far as both structure and properties. The unique and tuneable properties of nanostructured ZnO shows excellent stability in chemically as well as thermally stable n-type semiconducting material with wide applications such as in luminescent material, supercapacitors, battery, solar cells, photocatalysis, biosensors, biomedical and biological applications in the form of bulk crystal, thin film and pellets. The nanosized materials exhibit higher dissolution rates as well as higher solubility when compared to the bulk materials. This review significantly focused on the current improvement in ZnO-based nanomaterials/composites/doped materials for the application in the field of energy storage and conversion devices and biological applications. Special deliberation has been paid on supercapacitors, Li-ion batteries, dye-sensitized solar cells, photocatalysis, biosensors, biomedical and biological applications. Finally, the benefits of ZnO-based materials for the utilizations in the field of energy and biological sciences are moreover consistently analysed.

3D nanorhombus nickel nitride as stable and cost-effective counter electrodes for dye-sensitized solar cells and supercapacitor applications

Transition metal nitride based materials have attracted significant interest owing to their excellent properties and multiple applications in the field of electrochemical energy conversion and storage devices. Herein we synthesize 3D nanorhombus nickel nitride (Ni₃N) thin films by adopting a reactive radio frequency magnetron sputtering process. The as-deposited 3D nano rhombus Ni₃N thin films were utilized as cost-effective electrodes in the fabrication of supercapacitors (SCs) and dye-sensitized solar cells (DSSCs). The structure, phase formation, surface morphology and elemental composition of the as-deposited Ni₃N thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM). The electrochemical supercapacitive performance of the Ni₃N thin films was examined by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques, in 3 M KOH supporting electrolyte. The areal capacitance of the Ni₃N thin film electrode obtained from CV analysis was 319.5 mF cm⁻² at a lower scan rate of 10 mV s⁻¹. Meanwhile, the Ni₃N thin film showed an excellent cyclic stability and retained 93.7% efficiency of its initial capacitance after 2000 cycles at 100 mV s⁻¹. Interestingly, the DSSCs fabricated with a Ni₃N CE showed a notable power energy conversion efficiency of 2.88% and remarkable stability. The prominent performance of the Ni₃N thin film was ascribed mainly due to good conductivity, high electrochemically active sites with excellent 3D nano rhombus structures and high electrocatalytic activity. Overall, these results demonstrate that the Ni₃N electrode is capable of being considered for efficient SCs and DSSCs. This investigation also offers an essential directive for the advancement of energy storage and conversion devices.

Self-supported 3D nano-rhombus (nano-diamond) shaped Ni₃N coated on FTO glass which serves as a CE in DSSCs and supercapacitors. .

Bifunctional electro-catalytic performances of CoWO4 nanocubes for water redox reactions (OER/ORR)

In this paper, we report the synthesis of cube shaped nanoparticles of CoWO₄ (∼30 nm) by molten salts and their bifunctional electro-catalytic activities in water redox reactions for oxygen evolution and oxygen reduction reactions (OER and ORR).

Phyllanthus emblica seed extract mediated synthesis of PdNPs against antibacterial, heamolytic and cytotoxic studies

Ecofriendly synthesis of Palladium nanoparticles (PdNPs) were achieved using Phyllanthus emblica (P. emblica) seeds as reducing agent. Further the ecofriendly synthesized PdNPs were subjected for various analytical techniques like UV-Vis, FT-IR, XRD, Zeta potential, SEM and TEM. The results indicated that green synthesized PdNPs were spherical in shape with average particle size of 28±2nm with moderate stability. Further the synthesized PdNPs and extract were subjected for its antibacterial studies against various disease causing pathogens by agar well diffusion method. Seed extract resulted in 8.9±1.46mm against B. subtilis and PdNPs showed 9.6±1.10mm against S. aureus and synthesized PdNPs and extract were tested for hemolytic which resulted in 20% and 10% respectively. Toxicity studies were done against Artemia salina (A. salina). The LC₅₀ value of green synthesized P. emblica capped PdNPs and the P. emblica seed extract were found to be less toxic for A. salina with a value of 1.00μg/mL and 1.25μg/mL. In addition samples were checked for in vitro cytotoxicity assays on HeLa cell lines.

Catalytic application of non-toxic Persia americana metabolite entrapped SnO2nanoparticles towards the synthesis of 3,4-dihydroacridin-1(2H)-ones

Synthesized green SnO₂NPs were utilized in organic synthesis. Catalytic application was explored to synthesize 3,4-dihydroacridin-1(2H)-ones.

Facile synthesis of Fe3O4nanorod decorated reduced graphene oxide (RGO) for supercapacitor application

We describe a facile approach for the synthesis of RGO–Fe₃O₄nanorod nanocomposites for high performance supercapacitor application.

The use of ureteral stents and suprapubic catheter in vesicoureteric reflux surgery

The use of ureteric stents in reimplantation surgery is important. The younger the patient, the more important the stenting of ureters post reimplantation becomes, because even minimal oedema following surgery will produce ureteric obstruction unless stents are in place. JJ stents are now the preferred method of choice in ureteric reimplantation surgery, but in the past the patient required another admission to hospital and general anaesthetic to have the stents removed endoscopically. We describe a technique whereby the stents are attached to the suprapubic catheter and are therefore removed prior to the patient's discharge from hospital, thus obviating the need for a second admission and second anaesthetic for the stent removal. We have studied 23 patients with this technique and find that it is a reliable and safe method to use.

A prospective comparison of tissue glue versus sutures for circumcision

The safety of wound closure with tissue glue after surgery has been well established. The efficacy of its use in circumcision is poorly documented. The aim of this study was to carry out a comparative study of tissue glue versus suture closure after circumcision. The duration of the operative procedure, pain score, cosmesis and postoperative complications were evaluated. There were no complications in either group. There was no statistically significant difference in the pain score in both groups. However the mean time taken for tissue glue was 16.6 minutes and the mean time taken for sutures was 23.7 minutes. (p < 0.0001) which was statistically significant. The cosmetic appearance was found to be superior in the tissue glue group as there were no suture marks on the join of the shaft skin and foreskin base.

Adenomatous hyperplastic polyp of the gall bladder associated with cholelithiasis in a child

Polyps of the gall bladder are uncommon conditions in children. We present a case report of a 14-year-old girl who had calculous cholecystitis and an adenomatous hyperplastic polyp of the gall bladder. She was treated by laparoscopic cholecystectomy.