Highly Flame-Retardant Rigid Polyurethane Foams Prepared Using Corn Oil

One of the biggest catastrophic problems worldwide is the structural fire that destroys properties, durable goods and lives. Polyurethanes are one of the most important polymers because of the widely use in industrial applications, such as thermal insulation, coating, construction and automobiles. However, polyurethane foams have the disadvantage of being flammable. Most of the starting materials for the production of polyurethanes are derivate from petroleum-based resources, which generates environmental and governmental problems. In this study, bio-based rigid polyurethane foams were synthesized using corn oil. First, commercial corn oil was fully epoxidized to be used in the synthesis of flame-retardant rigid polyurethane foams using different concentrations of phosphorous containing polyol. Flame retardancy was tested on these foams and it was observed that phosphorous containing polyol from epoxidized corn oil provides excellent flame retardancy. It was observed burning time and weight loss decreased drastically for the foams containing only 1.5 wt% phosphorous. Second, commercial corn oil was partially epoxidized to be used in the synthesis of flame-retardant rigid polyurethane foams using different concentrations of phosphorous containing polyol. Partially epoxidation corn oil was converted to polyol using thiol-ene click chemistry. Flame retardancy for these foams was also studied and results showed that physicomechanical properties, such as density, closed cell content and compressive strength maintained the range of industrial applications. The efficiency in flame-retardant properties was achieved even for a small amount of phosphorous. From the overall study, the rigid polyurethane foams prepared using corn oil based-phosphorous containing polyol displayed high flame-retardancy

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

High Performance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of similar to 510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of similar to 1.55 F/cm(2) at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited similar to 65% improvement at 70 degrees C compare to that at 10 degrees C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices

The physicochemical investigation of hydrothermally reduced textile waste and application within carbon-based electrodes

Textile waste is on the rise due to the expanding global population and the fast fashion market. Large volumes of textile waste are increasing the need for new methods for recycling mixed fabric materials. This paper employs a hydrothermal conversion route for a polyester/cotton mix in phosphoric acid to generate carbon materials (hydrochars) for electrochemical applications. A combination of characterization techniques revealed the reaction products were largely comprised of two major components. The first is a granular material with a surface C : O ratio of 2 : 1 interspersed with phosphorous and titanium proved using energy dispersive X-ray spectroscopy, and the other is a crystalline material with a surface C : O ratio of 3 : 2 containing no phosphorous or titanium. The latter material was found via X-ray diffraction and differential scanning calorimetry to be terephthalic acid. Electrochemical experiments conducted using the hydrochar as a carbon paste electrode demonstrates an increase in current response compared to carbon reference materials. The improved current responses, intrinsically related to the surface area of the material, could be beneficial for electrochemical sensor applications, meaning that this route holds promise for the development of a cheap recycled carbon material, using straightforward methods and simple laboratory reagents

Facile synthesis of bio-template tubular MCo2O4 (M = Cr, Mn, Ni) microstructure and its electrochemical performance in aqueous electrolyte

In this project, wepresent a comparative study of the electrochemical performance for tubular mco2o4 (M = Cr, Mn, Ni) microstructures prepared using cotton fiber as a bio-template. Crystal structure, surface properties, morphology, and electrochemical properties of mco2o4 are characterized using X-ray diffraction (XRD), gas adsorption, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), cyclic voltammetry (CV), and galvanostatic charge-discharge cycling (GCD). The electrochemical performance of the electrode made up of tubular mco2o4 structures was evaluated in aqueous 3M KOH electrolytes. The as-obtained templated mco2o4 microstructures inherit the tubular morphology. The large-surface-area of tubular microstructures leads to a noticeable pseudocapacitive property with the excellent electrochemical performance of NiCo2O4 with specific capacitance value exceeding 407.2 F/g at 2 mV/s scan rate. In addition, a Coulombic efficiency ~100%, and excellent cycling stability with 100% capacitance retention for mco2o4 was noted even after 5000 cycles. These tubular mco2o4 microstructure display peak power density is exceeding 7000 W/Kg. The superior performance of the tubular mco2o4 microstructure electrode is attributed to their high surface area, adequate pore volume distribution, and active carbon matrix, which allows effective redox reaction and diffusion of hydrated ions

Bio-inspired NiO/ZrO2 mixed oxides (NZMO) for oxygen evolution reactions: from facile synthesis to electrochemical analysis

Background: Earth's abundant natural materials can be exploited for their potential in producing economically viable and sustainable electrocatalysts for clean energy generation. Herein, we employed a low cost and environmentally benign synthesis approach using plant extract as capping agent to synthesize bimetallic NiO/ZrO2 (nickel/Zirconiu mixed oxides; NZMO), and then studied their electrocatalytic properties. Results: The synthesized material was characterized for its elemental, compositional and morphological feature elucidation. The phytocapping agents were probed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GC–MS) which confirmed the active contribution of phytocompounds in synthesis as capping and stabilizing agents. Elemental and X-ray photoelectron spectroscopic (XPS) analysis manifested the presence of Ni, Zr and O content with morphological elucidations representing well-defined structures. The synthesized material was systematically investigated for electrocatalytic performance towards an oxygen evolution reaction (OER). Electrochemical testing showed that the NZMO exhibits remarkable enhanced catalytic activity with 0.39 V overpotential value and 72 mV dec−1 Tafel value at an existing density of 10 mA cm−2, which is comparable to that of precious metal catalysts. Conclusion: Experimental investigation demonstrates that the remarkable OER performance of NZMO could be attributed to intrinsic catalytic properties originating as a result of binary materials. Moreover, the organic compounds involved in the synthesis mechanism also could be the major contributors in terms of provision of active sites due to protons. Thus, the present work presents a promising electrocatalytic material using mixed metal oxides and paves a novel path toward the green synthesis of binary oxides with improved electrocatalytic performance