High-surface-area carbon-based capacitors exhibit significant advantages relative to conventional graphite-based systems, such as high power density, low weight, and mechanical flexibility. In this work, novel porous carbon-based electrodes were obtained from commercial cotton fibers (CFs) impregnated with graphene oxide (GO) at different dipping times. A subsequent thermal treatment under inert atmosphere conditions enables the synthesis of electrodes based on reduced GO (RGO) supported on carbon fibers. Those synthetized with 15 min and 30 min of dipping time displayed high specific capacitance given their optimal micro-/ mesoporosity ratio. Particularly, the RGO/CCF15A supercapacitor reports a remarkable specific capacitance of 74.1 F g−1 at 0.2 A g−1 and a high cycling stability with a 97.7% capacitive retention, making this electrode a promising candidate for supercapacitor desi...

La producción de plástico se ha incrementado dramáticamente en los últimos años, lo cual genera grandes impactos en el ambiente, como el incremento de las emisiones de gases de efecto invernadero y la contaminación del agua. Es necesario proponer e implementar estrategias para reducir los residuos plásticos que afectan el ambiente y convertirlos en productos de alto valor agregado como el carbón activado (CA), el cual presenta múltiples aplicaciones en el área de investigación y la purificación de agua. En esta tesis se realiza una propuesta de plan estratégico con enfoque de economía circular para la producción de CA a partir del diseño de una planta utilizando como materia prima residuos plásticos de un solo uso, con una capacidad para producir 185,9 kg de CA /día a partir de 1 t de plástico. En el análisis económico se calculó el valor actual neto (203608 soles),...

Los óxidos de cobalto (Co3O4) son de gran interés para su uso en supercapacitores (SCs) por su alta capacitancia teórica, baja toxicidad y costo. En este estudio, se sintetizó Co3O4 mediante la calcinación del ZIF-67 y se caracterizó fisicoquímica y estructuralmente con espectroscopia infrarroja (IR) y Raman, difracción de rayos X (DRX) además de microscopía electrónica de barrido (SEM-EDS). Para el ZIF-67, los espectros IR muestran enlaces Co-N asociados a la coordinación del cobalto con el 2-metilimidazol, además, los patrones de difracción confirman la estructura cristalina típica del material. Para los óxidos resultantes de la calcinación del ZIF-67 se evidencia la presencia de enlaces Co-O asociados a la estructura de espinela del Co3O4, además de presentar una estructura cristalina típica. Por otro lado, la evaluación electroquímica reveló que los Co3O4 tienen...

It is nowadays widely accepted that sweet taste perception is elicited by the activation of the heterodimeric complex T1R2-T1R3, customarily known as sweet taste receptor (STR). However, the interplay between STR and sweeteners has not yet been fully clarified. Here through a methodology coupling molecular dynamics and the independent gradient model (igm) approach we determine the main interacting signatures of the closed (active) conformation of the T1R2 Venus flytrap domain (VFD) toward aspartame. The igm methodology provides a rapid and reliable quantification of noncovalent interactions through a score (Δginter) based on the attenuation of the electronic density gradient when two molecular fragments approach each other. Herein, this approach is coupled to a 100 ns molecular dynamics simulation (MD-igm) to explore the ligand-cavity contacts on a per-residue basis as well as a series ...

Anodic electrogeneration of molecular chlorine from sodium chloride in an electrolytic cell produces a hypochlorous acid solution in an aqueous medium. This mixture of chloride and hypochlorous was used to leach gold from alluvial ore to its complex forms, [AuCl2]-, [AuCl4]-. The optimal amounts of NaCl in a neutral medium for gold leaching was 10 g L-1, while at pH 2, with a fixed NaCl concentration of 10 g L-1 it was observed a gold leaching increment of 70.4%. The addition of sodium hypochlorite to a solution of sodium chloride at pH 2 shows that it is the chloride oxidized product that performs the function of oxidant and can be used successfully for gold recovering from alluvial ore without the use of mercury.

SnO2 electrodes doped with Sb were prepared, supported on porous titanium sheets by impregnation, sintering and thermal decomposition of precursor solutions with different mass percentages of Sn and Sb (Sn: Sb = 9:1 and Sn: Sb = 7:3). The electrodes were coated with a layer of ß-PbO2 obtained by anodic electrodeposition method at 65 ° C and a current density of 30 mA cm-2, for 30 minutes. The electrodes were characterized by Raman spectroscopy, scanning electron microscopy, and cyclic voltammetry. The results obtained showed that the catalyst with the highest content of Sn provides the optimal conditions for the interlayer formation between Ti and PbO2 , such as the formation of a homogeneous film, low overpotentials for the chlorine evolution reaction and stability at neutral pH. The synthesized PbO2 film presented a pyramidal shape morphology, according to the Raman spectrum; it has ...

Green hydrogen is a valuable energy source able to overcome the environmental issues generated by fossil fuel consumption. In this regard, large-scale production of green hydrogen could be achieved by anion exchange membrane water electrolyzer (AEMWE). However, highly electroactive, and low-cost catalysts for hydrogen evolution reaction (HER) are critical to executing AEMWE. With this end in view, a straightforward route is revealed to improve the catalytic performance toward the HER of commercial and low-cost Ni foam electrodes. Indeed, an oxyhydroxide nickel-based surface was obtained after a facile and low-cost anhydrous etching procedure of the raw material. The novel catalyst reveals an onset potential for the HER of ca. 10.0 mV (vs. RHE), which is very close to the thermodynamic value, and an increment of the catalytic efficiency towards the HER. Furthermore, differential electroch...

The present study reports the simultaneous determination of dipyrone and codeine by a simple, fast and low-cost method using carbon black paste electrode (CBPE) modified with α-cyclodextrin (CD) and hierarchical porous carbon (HPC). Using optimum conditions, the CD-HPC/CBPE sensor proposed in this study presented excellent electrochemical catalysis. Based on square wave voltammetry (SWV) analysis, linear concentration ranges of 0.46 to 35 µmol L−1 and 0.5 to 38 µmol L−1 were obtained for dipyrone and codeine, respectively, with nanomolar limits of detection for both analytes. The proposed sensor exhibited good stability, satisfactory repeatability and high sensibility in the determination of the analytes of interest. The application of the sensor in real samples was found to be successful, with recovery rates ranging from 96 to 106%. The method proposed in this study was found to ...

jquinof@ulima.edu.pe;fparedes@ulima.edu.pe;esaetton@ulima.edu.pe;reyzagui@ulima.edu.pe

This work was supported by Peruvian government agencies CONCYTEC and FONDECYT/World Bank (contract 026-2019 FONDECYT-BM-INC.INV) and the Sao Paulo Research Foundation (FAPESP) through the fellowships granted to J. M. G. (FAPESP 2018/16896-7).

The Peruvian government agencies CONCYTEC and FONDECYT/World Bank (contract 026-2019 FONDECYTBMINC.INV) .

This work reports the fabrication of a novel electrochemical sensor for the detection of the complex ion [Cu(CN)3](aq)2−, one of the main components of the effluents from cyanide alkaline copper plating baths. This sensor was prepared by using a surface modified glassy carbon (GC) electrode with 1,8-dihydroxyantroquinone (1,8-DHAQ). It was characterized by electrochemical impedance, Raman spectroscopy and UV–Visible spectroscopy. The electrochemical detection of [Cu(CN)3](aq)2−was performed by differential pulse voltammetry. The 1,8-DHAQ/GC electrochemical sensor exhibits good reproducibility and a linear range of 5.50 × 10−7–3.81 × 10−6 mol L−1, with a detection limit (LOD) of 1.20 × 10−6 mol L−1, quantification limit (LOQ) of 3.97 × 10−6 mol L−1, and robustness to interfering Cl−, NO3−, SO42− y CO32− ions. Finally, a DFT approach suggests an almost par...