Study on the specific capacitance of an activated carbon cloth modified with reduced graphene oxide and polyaniline by cyclic voltammetry

On the behaviour of Atrazine removal from water using fabrics as anodes and cathodes

This study examines the degradation of atrazine (ATZ) with Pt-modified textile electrodes using an electrochemical method that is comparatively studied in two electrochemical cell configurations: cells with separated anodic and cathodic compartments (divided configuration); and without any separation (undivided configuration). The influence of the presence of chloride ions was studied. The best results were obtained when an undivided cell was used. The morphology and composition of the dispersed Pt coatings were analyzed using field emission scanning electron microscopy (FESEM) and Energy Dispersive X-Ray Analysis. The FESEM analyses confirmed that the textile surface was effectively modified by the electrocatalytic material. High performance liquid chromatography, gas chromatography mass spectrometry, and spectroscopic methods were used to follow the evolution of major oxidation products. Total organic carbon, chemical oxygen demand, and total nitrogen were used to evaluate the degradation efficiency of treated aqueous solutions. The experimental results obtained indicate that the efficiency of the electrochemical treatment was high with a low energy consumption when using electrodes based on textile materials, such as anodes or as cathodes (in particular, in electrolysis without compartment separation). All these can be produced at very competitive prices.

Multifunctionality exploration of NiCo2O4-rGO nanocomposites: photochemical water oxidation, methanol electro-oxidation and asymmetric supercapacitor applications

Different weight percentages of NiCo₂O₄-rGO nanocomposites were prepared via a facile hydrothermal method. The prepared nanocomposites were structurally and morphologically characterized by X-ray diffraction, Raman spectroscopy, and electron microscopy. The structural studies show the formation of rGO-NiCo₂O₄ nanocomposites by embedment of porous NiCo₂O₄ rods on rGO sheets. The effect of the NiCo₂O₄ content on photochemical water oxidation was investigated. It revealed that the catalysts NiCo₂O₄-rGO with 1 : 26 ratio (NCO26) and 1 : 13 ratio (NCO13) are efficient in generating oxygen under light illumination. It proves that NCO26 works far more effectively as a photocatalyst compared to NCO13. Methanol electro-oxidation of the NCO26 nanocomposite shows a current density of 24 mA cm^-2 at a potential of 0.45 V in cyclic voltammetry and maintains the current for 3600 s at 0.45 V in chronoamperometry. An onset potential of 0.344 V was observed for 0.5 M methanol oxidation. The specific capacitance values were found to be 354.75 F g^-1 and 375.32 F g^-1 at 1 mV s^-1 and 1 A g^-1, respectively, for NCO26 in supercapacitor studies. The charge stored via capacitive and diffusion-controlled processes was determined using Power's law and Trasatti plot. An asymmetric supercapacitor device shows a specific capacitance of 122.2 F g^-1 at a current density of 1 A g^-1 and exhibits a retention of 74.3% after 5000 cycles. An energy density of 67.89 W h kg^-1 and a power density of 1 kW kg^-1 at a current density of 1 A g^-1 are observed.

Photocapacitive CdS/WOx nanostructures for solar energy storage

Through a facile solvothermal procedure, a CdS/WO_x nanocomposite has been synthesised which exhibits photocapacitive behaviour under white light illumination at a radiant flux density of 99.3 mW cm⁻². Photoelectrochemical experiments were undertaken to examine the self-charging properties of the material and to develop an understanding of the underlying electronic band structure responsible for the phenomenon. By employing XPS, UPS and UV-Vis diffuse reflectance spectroscopy for further characterisation, the ability of the composite to generate current following the removal of incident light was related to the trapping of photoexcited electrons by the WO_x component. The presence of WO_x yielded an order of magnitude increase in the transient photocurrent response relative to CdS alone, an effect attributed to the suppression of electron-hole recombination in CdS due to hole transfer across the CdS/WO_x interface. Moreover, current discharge from the material persisted for more than twenty minutes after final illumination, an order of magnitude improvement over many existing binary composites. As a seminal investigation into the photocapacitive characteristics of CdS/WO_x composites, the work offers insight into how the constituent materials might be utilised as part of a future self-charging solar device.

Telas de carbón activado: generalidades y aplicaciones

Los carbones activados (CA) son de gran interés debido a las excepcionales propiedades físicas y químicas que poseen, estos materiales se presentan en forma de gránulos o polvos, pero recientemente se ha comercializado una nueva forma de CA conocida como Fibra de Carbón Activado (FCA), que se puede fabricar en dos presentaciones, como tela y como fieltro. Las Telas de carbón activado (TCA) son materiales que poseen excelentes propiedades que las hacen superiores en comparación con las formas tradicionales y se producen a partir de precursores, mediante diversos procesos que incluyen activación física o química, entre los agentes impregnantes más utilizados se encuentran el KOH, H3PO4, ZnCl2, AlCl3, NH4Cl, Na2CO3 y K2CO3, cuya función principal es servir como deshidratantes impidiendo al mismo tiempo la producción de alquitranes. Las características y propiedades que adquieren las TCA dependen de la naturaleza del material que se utilizó para producirlas, estas características han sido aprovechadas en una gran cantidad de aplicaciones, como: medicina, sistemas de soporte de catalizadores, en la industria para la adsorción de contaminantes, purificación de aguas y tratamiento de aguas residuales, entre otras. Esta revisión muestra las generalidades y aplicaciones en estudios recientes y resume las aplicaciones de las TCA de las diferentes investigaciones realizadas, así como su proceso de obtención.