In search of affordable, flexible, lightweight, efficient and stable supercapacitors, metal oxides have been shown to provide high charge storage capacity but with poor cyclic stability due to structural damage occurring during the redox process. Here, we develop an efficient flexible supercapacitor obtained by carbonizing abundantly available and recyclable jute. The active material was synthesized from jute by a facile hydrothermal method and its electrochemical performance was further enhanced by chemical activation. Specific capacitance of 408 F/g at 1 mV/s using CV and 185 F/g at 500 mA/g using charge-discharge measurements with excellent flexibility (~100% retention in charge storage capacity on bending) were observed. The cyclic stability test confirmed no loss in the charge storage capacity of the electrode even after 5,000 charge-discharge measurements. In addition, a supercapacitor device fabricated using this carbonized jute showed promising specific capacitance of about 51 F/g, and improvement of over 60% in the charge storage capacity on increasing temperature from 5 to 75 °C. Based on these results, we propose that recycled jute should be considered for fabrication of high-performance flexible energy storage devices at extremely low cost.

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. Our 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.

A novel bio-based polyol was synthesized using corn oil and 2-mercaptoethanol via thiol-ene reaction as an alternative to petroleum-based polyol for the synthesis of polyurethane foams. The polyol was analyzed using wet chemical techniques to obtain hydroxyl number and viscosity. Infrared spectroscopy and gel permeation chromatography were used to confirm the structural properties of the foams. Flame-retardant polyurethane foams were prepared by the addition of different concentrations of dimethyl methyl phosphonate (DMMP) in final foam composition. The effect of DMMP on the thermo-mechanical properties of the polyurethane foams was analyzed. The TGA analysis showed improved stability of the final char with addition of DMMP in the foams. All the foams maintained a well-defined cellular structure and over 95% of closed cell content. The horizontal burning test showed reduced burning time and weight loss from 115 s and 38 wt.% for the neat foams, to 3.5 s and 5.5 wt.% for DMMP-containing foams (1.94 wt.% P). The combustion test using cone calorimeter showed a considerable reduction in heat release rate and total heat release. Thus, our study shows that corn-oil based polyol can be used to produce renewable polyol for industrially producible rigid polyurethane foams. The addition of a small amount of DMMP could result in a significant reduction in the flame-retardant properties of the polyurethane foams.