Nanosheets of CuCo₂O₄ as a High-Performance Electrocatalyst in Urea Oxidation

The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo₂O₄ grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo₂O₄ towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo₂O₄ grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo₂O₄ electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo₂O₄ electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. The study suggests that the CuCo₂O₄ electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost

Molybdenum Oxides for Energy Generation and Storage Using Efficient Clean Method

To solve the growing energy issues, significant efforts have been focused on the search of earth-abundant ele­ments that can provide multifunctional behavior for both energy generation and storage. Due to the low-cost and rich chemical nature, transition metal oxide nanostructures have been used in the fabrication of energy devices, such as fuel cells and lithium batteries. In this work, nickel, cobalt and iron molybdates were synthesized via a simple hydrothermal method in order to fabricate electrodes for oxygen evolution reaction (OER) and a superca­pacitor. FeMoO₄ required an overpotential of 294 mV to achieve a current density of 10 mA/cm2 for oxygen evolution reaction, which is lower than the overpotential required for NiMoO₄ and CoMoO₄ to do the same process. For the energy storage properties, the highest specific capacitance was achieved by FeMoO₄ electrode (11.5 F/cm2 at a current density of 1 mA/cm2). Galvanostatic charge-discharge measurements were performed and showed a better discharge time for iron molybdate. The capacitance retention and coulombic efficiency ex­hibited excellent performance over 5,000 cycles. In conclusion, molybdates, mainly FeMoO₄, could be a promis­ing material for the advancement of energy generation and storage devices

Metal-Doped Catalysts for Hydrogen Evolution Reaction

The highly efficient electrochemical hydrogen evolution reaction (HER) provides a promising way to solve energy and environment problems. In this work, various transition metals (Fe, Co, Ni, Cu, Ag, and Pt) were selected to support on molybdenum carbides by a simple organic-inorganic precursor carburization process. X-ray diffraction (XRD) analysis results indicated that the ß-MO₂C phase was formed in all metal-doped samples. X-ray photo­electron spectroscopy analysis indicated that the binding energy of MO₂+ species (MO₂C) shifted to a lower value after metal was doped on the molybdenum carbide surface. Comparing with pure ß-MO₂C, the elec­trocatalytic activity for HER was improved by transition metal doping on the surface. Remarkably, the catalytic activity improvement was more obvious when Pt was doped on molybdenum carbide (2% Pt-MO₂C). The 2% Pt-MO₂C required a ?_10 of 79 mV, and outperformed that of pure ß-MO₂C (?10 = 410 mV) and other transition metal doped molybdenum carbides, with a small Tafel slope (55 mV/dec) and a low onset overpo­tential (32 mV) in 0.5 M H₂SO₄. Also, the 2% Pt-MO₂C catalyst demonstrated a high stability for the HER in 0.5 M H₂SO₄. This work highlights a feasible strategy to explore efficient electrocatalysts with low cost via engineering on the composition and nanostructure

Pomegranate: An Eco-Friendly Source for Green Energy Storage Devices

With an increasing demand for energy and concerns about the environment, scientists are trying to find a better way to generate green energy and to efficiently store the generated energy. Biowaste could be an attractive source for the preparation of active materials for energy storing devices. In this project, a shell of pomegranate was used for the preparation of high surface area carbon for supercapacitor applications. The dry powder of a pomegranate was chemically activated using various ratios of pomegranate and activating agent to produce carbon with a range of different properties. The surface area of the pomegranate-based carbon was 40 m2/g, which improved to 1459, 1737, and 2189 m2/g upon chemical activation using, 1:1, 1:2, and 1:3 ratios of pomegranate: activating agent, respectively. The energy storage capacity was calculated using galvanostatic charge-discharge measurements, and the highest specific capacitance of 190 F/g at 1 A/g was observed for PG-2 (1:2 ratio of pomegranate: activating agent) activated pomegranate-based carbon. Using the electrode, the symmetric supercapacitor devices were fabricated utilizing various electrolytes (aqueous, organic, and ionic liquid electrolytes). From the Ragone curve, the highest energy and power density of [8.8 Wh kg-1, 3,950 W kg-1], [39 Wh kg-1, 8,943 W kg-1], and [68 Wh kg-1, 11,316 W kg-1] was obtained for aqueous, organic, and ionic liquid electrolytes, respectively. Our research suggests that pomegranate-based carbon could be an attractive material for the fabrication of energy storage devices

EFFECT OF pH, SELECTED CYCLODEXTRINS AND COMPLEXATION METHODS ON THE SOLUBILITY OF LORNOXICAM

Objective: The objective of the present study is to investigate the effect of pH, selected cyclodextrins and methods of complexation on the solubility of lornoxicam. Methods: Phase solubility studies were carried out according to Higuchi and Connors. Inclusion complexes of lornoxicam were prepared by different methods like kneading, ultrasoncation, spray drying along with the physical mixtures using β cyclodextrin and hydroxypropyl β cyclodextrins. Results: Lornoxicam being weakly acidic drug showed extremely low solubility in the acidic medium (pH 1.2) and poor solubility in water. The solubility of the drug increased as the pH of the medium was subsequently increased up to 7.4 and a drastic increase in solubility perhaps several hundred folds was observed with the alkaline phosphate buffer (pH 10.0). Phase solubility studies revealed that, hydroxypropyl β cyclodextrin (HP β CD) up to the concentration of 20 mM showed a linear increase in solubility of lornoxicam whereas the solubility of lornoxicam was increased up to β cyclodextrin (β CD) concentration of 14 mM and beyond that the solubility of the drug reduced probably due to precipitation of the complexes. The stability constant (Ks) was found to be 378.55 M-1 and 867.262 M-1 for β CD and HP β CD respectively. Inclusion complexes of lornoxicam with cyclodextrins were prepared employing different methods and the effect of complexation methods on the dissolution of lornoxicam was studied. Dissolution studies revealed that, irrespective of the cyclodextrins used (β CD and HP β CD), highest drug release rate was observed from the spray dried products compared to those prepared by kneading and ultrasonication methods. Inclusion complexes prepared using HP β CD showed higher drug release compared to those prepared using β CD. Conclusion: The study demonstrated the distinctive pH dependent of solubility of lornoxicam and also showed that cyclodextrins especially HP β CD can be utilized to improve the solubility of lornoxicam

Vitamin D status in pregnant women and their newborns in a tertiary care hospital

Background: In the recent years there has been an increased understanding of the role that vitamin D plays in regulation of cell growth, calcium absorption and immunity and its impact on the developing fetus and maternal health is of significant concern. This study aims at evaluating the Vitamin D status in pregnant women and their newborns.Methods: A cross sectional study was done on 100 pregnant females according to inclusion and exclusion criteria. At the time of delivery, maternal blood was collected, and newborn samples were taken from newborn side of umbilical cord and sent for analysis.Results: The prevalence of Vitamin D deficiency has been found to be 85% of pregnant females and 91% of the newborns. Only 5% of pregnant females and 1% of the newborns showed Vitamin D sufficiency. Maternal and newborn vitamin D levels show a positive correlation. Mean maternal and newborn Vitamin D levels were found to be 16.78±7.04 ng/mL and 11.29±5.75 ng/ml.Conclusions: Vitamin D deficiency is highly prevalent among pregnant women in north India. Low maternal vitamin D levels lead to vitamin D deficiency in the newborns also

Apomixis and polyembryony in the guggul plant, Commiphora wightii

The present report is a part of our study on the reproductive biology of a traditional Indian medicinal plant,Commiphora wightii, a source of guggul steroids. Field examination showed a predominantly large number of isolated and groups of female individuals. Only one andromonoecious and two exclusively male plants were recorded. Female plants set seed irrespective of the presence or absence of pollen. Hand-pollination experiments and embryological studies have confirmed the occurrence of non-pseudogamous apomixis, nucellar polyembryony and autonomous endosperm formation for the first time in this plant, which is presently threatened by over-exploitation

Electrocatalytic Properties of Lanthanum-based Perovskites for Water Splitting and Energy Storage Applications

Recent changes in global weather patterns have punctuated the need for mollification through a cleaner energy option. As part of the plan, hydrogen production for fuel cells offers substantial power without carbon emissions. Overall water splitting, with the aid of a low cost electrocatalyst could prove to be an abundant green fuel source. Utilizing readily available transition metals, three perovskite nanostructures were studied as a multifunctional material for hydrogen production as well as energy storage. LaCoO₃ (LCO), LaFeO₃ (LFO), and LaMnO₃ (LMO) were synthesized and characterized by X-ray diffraction and then dip coated onto nickel foam as electrodes in a standard three electrode system. The electrochemical properties were analyzed with electrochemical impedance spectroscopy (EIS), line scan voltammetry (LSV), and cyclic voltammetry (CV) for its electro-catalytic activity towards both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) as well as its effectiveness as a supercapacitor. It was shown that electrocatalytic activity toward OER was highly dependent on the material composition. Accordingly, LFO had the lowest overpotential voltage of 316 mV at 10 mA/cm2 compared with 376 mV (LCO) and 419 mV (LMO). Toward HER, LMO showed overpotential voltage of 176 mV at 10 mA/cm2, while LCO and LFO showed 221 mV and 230 mV, respectively. Measured at a common current density of 0.5 A/g, the specific capacitance of LMO was 105 F/g over LCO (45 F/g) and LFO (35 F/g). Further investigation for fabrication of devices for energy storage and water splitting electrolyzer application has been considered