Application of crosslinked polybenzimidazole-poly(Vinyl benzyl chloride) anion exchange membranes in direct ethanol fuel cells

Crosslinked membranes have been synthesized by a casting process using polybenzimidazole (PBI) and poly(vinyl benzyl chloride) (PVBC). The membranes were quaternized with 1,4-diazabicyclo[2.2.2]octane (DABCO) to obtain fixed positive quaternary ammonium groups. XPS analysis has showed insights into the changes from crosslinked to quaternized membranes, demonstrating that the crosslinking reaction and the incorporation of DABCO have occurred, while the13C-NMR corroborates the reaction of DABCO with PVBC only by one nitrogen atom. Mechanical properties were evaluated, obtaining maximum stress values around 72 MPa and 40 MPa for crosslinked and quaternized membranes, respectively. Resistance to oxidative media was also satisfactory and the membranes were evaluated in single direct ethanol fuel cell. PBI-c-PVBC/OH 1:2 membrane obtained 66 mW cm−2 peak power density, 25% higher than commercial PBI membranes, using 0.5 bar backpressure of pure O2 in the cathode and 1 mL min−1 KOH 2M EtOH 2 M aqueous solution in the anode. When the pressure was increased, the best performance was obtained by the same membrane, reaching 70 mW cm−2 peak power density at 2 bar O2 backpressure. Based on the characterization and single cell performance, PBI-c-PVBC/OH membranes are considered promising candidates as anion exchange electrolytes for direct ethanol fuel cells.Fil: Herranz, Daniel. Universidad Autónoma de Madrid; EspañaFil: Coppola, Roxana Elisabeth. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Escudero Cid, Ricardo. Universidad Autónoma de Madrid; EspañaFil: Ochoa Romero, Kerly. Universidad Autónoma de Madrid; EspañaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Pérez Flores, Juan Carlos. Universidad de Castilla-La Mancha; EspañaFil: Canales Vázquez, Jesús. Universidad de Castilla-La Mancha; EspañaFil: Palacio, Carlos. Universidad Autónoma de Madrid; EspañaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Ocón, Pilar. Universidad Autónoma de Madrid; Españ

Propiedades de membranas conductoras de protones y oxhidrilos para celdas de combustible de alcohol directo.

Tesis de Doctorado en Ciencia y Tecnología Mención QuímicaLa membrana conductora de iones es uno de los componentes clave de una celda de combustible alimentada con alcohol (metanol o etanol) y oxígeno. Además de la sorción de agua y la conductividad eléctrica, la permeabilidad del alcohol a través de la membrana, que reduce la potencia de la celda, es otra propiedad importante a tener en cuenta. Este trabajo de tesis se focaliza en el estudio de estas propiedades en membranas de Nafion, basadas en un polímero conductor de protones y utilizadas en la gran mayoría de las celdas de combustibles tipo PEM (Proton Exchange Membrane), y en membranas de polisulfona cuaternizada, un polímero conductor de oxidrilos que podría utilizarse como medio conductor en celdas de combustible alcalinas.Fil: Abuin, Graciela Carmen. Universidad Nacional de San Martín. Instituto de Investigaciones e Ingeniería Ambiental. Comisión Nacional de Energía Atómica. Instituto de Tecnología "Prof. Jorge Sabato"; Buenos Aires, Argentin

Acid-doped ABPBI membranes prepared by low-temperature casting: Proton conductivity and water uptake properties compared with other polybenzimidazole-based membranes

Phosphoric acid doped ABPBI (poly [2,5-benzimidazole]) membranes were prepared with a new low temperature casting procedure (ABPBI-ET), and their water uptake and proton conductivity were measured. The results were compared with those of ABPBI casted at high temperature (ABPBI-MSA), poly [2-2′-(m-phenylene)-5-5′ bibenzimidazole] (PBI), and commercial cross-linked Fumatech ABPBI (ABPBI-C) membranes. The water uptake of ultra thin ABPBI-ET membranes in the range 7-30 nm supported over gold substrate, was also measured and compared with PBI ones. The in-plane proton conductivities of all the membranes were measured in the temperature range from 20° to 120°C at different water activities. The ABPBI-ET doped in 10.6 M H3PO4 and ABPBI-C doped in 14.9 M H3PO4 showed the highest conductivities, even higher than those reported for Nafion membranes. ABPBI-ET membranes showed a maximum as a function of water activity at aw ≈ 0.55, a behavior that can be rationalized in terms of the dissociation constant of the ABPBI-H3PO4 complexes calculated using the Scatchard method, and the H3PO4 concentration in the water inside the membrane.Fil: Díaz, Liliana Alicia. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Corti, Horacio Roberto. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Polyvinyl alcohol nanofibers reinforced with polybenzimidazole: Facile preparation and properties of an anion exchange membrane

The search of novel materials for anion exchange membranes (AEMs) is a key factor in addressing challenges of electrochemical energy conversion and storage devices in terms of cost, durability, efficiency, and up-scalability; and composite materials based in electrospun nanofibers have a great potential in this regard. We report a facile preparation method of an AEM composed by polyvinyl alcohol (PVA) nanofibers crosslinked with glutaraldehyde (GA) and reinforced with poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (ABPBI) polymer, characterizing it as an AEM in a liquid alkaline water electrolyzer (LAWE) device. Homogeneous and flexible membranes were obtained, with a good chemical stability in the doping solution (15 wt.% KOH), and better swelling resistance than pure ABPBI membranes. The membranes also showed a specific ionic conductivity of 36 mS·cm−1 at 60°C and 41 mS·cm−1 at 80°C, with an activation energy value of 3.5 kJ·mol−1. Regarding LAWE performances, it attained current densities of 236 and 271 mA·cm−2 for a 2 V cell voltage when operated at 50°C and 70°C, respectively. During chronopotentiometric test, neither potential drop nor change in material integrity were observed. These results provide a facile and scalable method for low cost AEMs preparation, contributing as an alternative material for its use in electrolyzers.Fil: Coppola, Roxana Elisabeth. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Molinari, Fabricio Nicolás. Instituto Nacional de Tecnología Industrial; ArgentinaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; Argentin

Effect of duty cycle on NiMo alloys prepared by pulsed electrodeposition for hydrogen evolution reaction

We report the influence of duty cycle in the range 30–70%, on NiMo alloys prepared on 316L stainless steel/Ni by pulsed electrodeposition and the characterization of their composition, morphology, and electrocatalytic activity towards hydrogen evolution reaction in alkaline medium. The morphology and Mo content were affected by varying the duty cycle between 70% and 30%, obtaining twice the Mo content and a more globular structure in the NiMo alloys prepared with a 30% duty cycle. The material presented a crystalline structure with peaks corresponding to the Ni (111) and (200) planes, which are independent of the duty cycle used. The cyclic voltammetry analysis showed a remarkable increment of the exchange current density when increasing the Mo content. This effect was attributed to changes in the electronic structure related to the nanostructure of the material. All the NiMo alloys analyzed showed activation to hydrogen evolution reaction after ageing, being that obtained at 30% duty cycle the one that showed the highest one. By analysis of electrochemical impedance spectroscopy, we found for duty cycle 70% a behaviour similar to that of NiMo synthesized by direct current techniques. In that catalyst, two processes were observed at different potentials while the NiMo30% catalyst shows several electrochemical processes occurring.Fil: Benavente Llorente, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; ArgentinaFil: Díaz, Liliana Alicia. Instituto Nacional de Tecnología Industrial; Argentina. EnergyLab; EspañaFil: Lacconi, Gabriela Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Franceschini, Esteban Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentin

3D nanostructured NiMo catalyst electrodeposited on 316L stainless steel for hydrogen generation in industrial applications

Nowadays, massive NiMo alloys are considered highly active catalysts for the hydrogen evolution reaction (HER) in industrial alkaline electrolysers. Thus, it is desirable to study other alternative materials, preserving the specific properties of these alloys. In this study, a NiMo coating on 316L stainless steel with high resistance to the corrosive medium is obtained by electrodeposition process. Properties and structural characteristics of the new synthesized material have been correlated with its efficiency as electrocatalyst. In this study, using a simple plating method, it was possible to obtain a material with a catalytic activity for the HER in alkaline media, which is 37.6 times higher than that of conventional raw Ni catalysts, at a considerably lower cost. The 3D nanostructured NiMo catalyst synthesized presented a highly roughened surface with porous microstructure, which is an essential requirement for obtaining high catalytic activity with this type of systems. The porous microstructure in the coating has been confirmed by X ray diffraction and scanning electron microscopy. Raman spectra of the surface evidenced the formation of superficial species before and after the ageing treatment by prolonged chronoamperometry in alkaline electrolyte. This feature was also confirmed by the analysis of X ray photoelectron spectroscopy measurements.Fil: Gomez, Melisa Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Diaz, Liliana A.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Franceschini, Esteban Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Lacconi, Gabriela Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; Argentin

A high selectivity quaternized polysulfone membrane for alkaline direct methanol fuel cells

Alkaline membranes based on quaternized poly(arylene ether sulfone) (QPAES) were characterized in relation to their water and methanol uptake, methanol permeability, electrical conductivity, and mechanicalproperties. The performance of QPAES as electrolyte in alkaline direct methanol fuel cells was studied using a free-breathing single fuel cell at room temperature. Methanol uptake by QPAES membranes is lower than water, while their methanol permeability, determined in the temperature range from 30 C to 75 C, was much lower than for Nafion membranes. Young modulus of QPAES membranes decrease with the degree of alkalization of the membrane, although mechanical properties are still satisfactory for fuel cell applications for membrane alkalized with 2 M KOH, which additionally exhibit optimal hydroxide conductivity. Although the specific conductivity of QPAES membranes was lower than that reported for Nafion, its methanol selectivity (conductivity/methanol permeability ratio), is much higher than that reported for Nafion 117, and a commercial amminated polysulfone. In view of these results, QPAES membranes are expected to exhibit promising performance as an electrolyte in alkaline direct methanol fuel cells.Fil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Franceschini, Esteban Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Nonjola, Patrick. No especifíca;Fil: Mathe, Mkhulu K.. No especifíca;Fil: Modibedi, Mmalewane. No especifíca;Fil: Corti, Horacio Roberto. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Polybenzimidazole-crosslinked-poly(vinyl benzyl chloride) as anion exchange membrane for alkaline electrolyzers

Zero-gap liquid alkaline water electrolyzers have great potential for hydrogen production. In order to enhance their actual performance, one of the key components to investigate is the anionic exchange membrane that allows the conduction of anions between the electrodes. This paper reports the preparation and characterization of membranes composed of a polybenzimidazole, either poly(2,5-benzimidazole) (ABPBI) or poly[2-2′-(m-phenylene)-5-5′-bibenzimidazole] (PBI), crosslinked with different ratios of poly(vinylbenzyl chloride) (PVBC), forming thermally stable and homogeneous films. Quaternization of these films with 1,4-diazabicyclo (2.2.2) octane (DABCO) followed by immersion in an alkaline solution lead to the introduction of quaternary ammonium groups and hydroxide anions respectively. Adequate thermal stability is observed in the temperature range of application (below 100 °C). Measurements of KOH and water and related swelling reflect the higher absorption capacity of ABPBI based membranes relative to PBI based ones. ABPBI-c-PVBC/OH 1:2 membranes at 50 °C are characterized by high ionic conductivity values (48 mS cm−1), reaching 380 mA cm−2 at cell voltage 1.98 V. In conclusion, we consider that these membranes are competitive candidates as anion exchange membranes for zero-gap alkaline water electrolyzers, and can be further enhanced to reach the performance of state of the art AEM's.Fil: Coppola, R.E.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Herranz, D.. Universidad Autónoma de Madrid; EspañaFil: Escudero Cid, R.. Universidad Autónoma de Madrid; EspañaFil: Ming, N.. Universidad Autónoma de Madrid; EspañaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Ocón, P.. Universidad Autónoma de Madrid; EspañaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; Argentin

Polybenzimidazole membrane for efficient copper removal from aqueous solutions

Thin films of poly(2,5-benzimidazole) (ABPBI) polymer were prepared by the casting method, and sorption studies with aqueous CuSO4 solutions were performed. Surface interaction between Cu(II) and the membrane was studied using spectroscopic analysis (Fourier transform infrared, Raman and X-ray photoelectron), showing a strong interaction through nitrogen groups of ABPBI and Cu(II). The best conditions for Cu(II) uptake were at pH = 5 and a soaking time of 60 min. In these conditions, the sorption isotherm was best fitted by the Langmuir equation and the maximum sorption capacity was estimated to be 1.5 mmol g−1. Due to sorption pH dependency, elution studies using hydrochloric acid solution were carried out, showing an almost complete removal of bonded Cu(II) when immersing the ABPBI membrane in the acidic solution. Surface morphology of membranes was studied using scanning electron microscopy–energy-dispersive X-ray spectroscopy, showing no major changes with sorption and elution experiments. These results show that ABPBI can be considered as an alternative polymer for the development of new materials for the removal of heavy metals.Fil: Coppola, Roxana Elisabeth. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Lozano, Hernan Ezequiel. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Contin, Mario Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Canneva, Antonela. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Molinari, Fabricio Nicolás. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; ArgentinaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Speciation and Proton Conductivity of Phosphoric Acid Confined in Mesoporous Silica

Phosphoric acid (PA) confined in a commercial mesoporous silica (CARIACT G) with porous size in the range of 3 to 10 nm was studied in relation to its coordination with the silanol groups on the silica surface as a function of temperature, up to 180 °C, using 31P and 29Si MAS NMR spectroscopy. As the temperature increases, the coordination of Si and P in the mesopores depends on the pore size, that is, on the area/volume ratio of the silica matrix. In the mesoporous silica with the higher pore size (10 nm), a considerable fraction of PA is nonbonded to the silanol groups on the surface, and it seems to be responsible for its higher conductivity at temperatures above 120 °C as compared to the samples with a smaller pore size. The electrical conductivity of the functionalized mesoporous silica was higher than that reported for other silico-phosphoric composites synthesized by sol−gel methods using soft templates, which require high-temperature calcination and high-cost reagents and are close to that of the best PA-doped polybenzimidazole membranes used in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). The rate of PA release from the mesoporous silica matrix when the system is exposed to water has been measured, and it was found to be strongly dependent on the pore size. The low cost and simplicity of the PA-functionalized mesoporous silica preparation method makes this material a promising candidate to be used as an electrolyte in HT-PEMFCs.Fil: Trevani, Liliana N.. Public Health Ontario; CanadáFil: Lépori, Cristian Marcelo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Garro Linck, Yamila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Monti, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Abuin, Graciela Carmen. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Vaca Chávez Fornasero, Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Corti, Horacio Roberto. Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología; Argentin