Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell

Huang, Wen-Yao; Jheng, Li‐Cheng; Hsieh, Tar‐Hwa; Ho, Ko‐Shan; Wang, Yen‐Zen; Gao, Yi-Jhun; Tseng, Po-Chih

doi:10.3390/polym12123070

Cited by 9 publications

(6 citation statements)

References 29 publications

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“…We demonstrated in Equation (1) that one O 2 molecule and one water molecule can be fully reduced to four hydroxyl ions (OH − ) by cathode catalysts in an alkaline solution, following the 4e-pathway. However, HO 2 − is an unavoidable intermediate by-product [ 30 , 31 , 32 , 33 , 40 ] due to the incomplete ORR (oxygen reduction reaction) in an alkaline medium (Equation (2)). Based on Equation (2), the reduction reaction can continue further after the supply of two additional electrons, the so-called 2e-pathway (Equation (2) plus Equation (3)).…”

Section: Resultsmentioning

confidence: 99%

“…To avoid the trouble of preparing the macrocyclic structure and the addition of a carbon matrix such as carbon black (CB), we have prepared many nitrogen-containing polymers (N polymers). The N polymers can chelate with cobalt ions (Co(II)) and calcine to create a Co–N–C structure [ 30 , 31 , 32 , 33 ] without the addition of any CB.…”

Section: Introductionmentioning

confidence: 99%

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2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Wang

Hsieh²,

Huang³

et al. 2023

Polymers

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In order to yield more Co(II), 2,6-diaminopyridine (DAP) was polymerized with 4,4-methylene diphenyl diisocyanates (MDI) in the presence of Co(II) to obtain a Co-complexed polyurea (Co-PUr). The obtained Co-PUr was calcined to become Co, N-doped carbon (Co–N–C) as the cathode catalyst of an anion exchange membrane fuel cell (AEMFC). High-resolution transmission electron microscopy (HR-TEM) of Co–N–C indicated many Co-Nx (Co covalent bonding with several nitrogen) units in the Co–N–C matrix. X-ray diffraction patterns showed that carbon and cobalt crystallized in the Co–N–C catalysts. The Raman spectra showed that the carbon matrix of Co–N–C became ordered with increased calcination temperature. The surface area (dominated by micropores) of Co–N–Cs also increased with the calcination temperature. The non-precious Co–N–C demonstrated comparable electrochemical properties (oxygen reduction reaction: ORR) to commercial precious Pt/C, such as high on-set and half-wave voltages, high limited reduction current density, and lower Tafel slope. The number of electrons transferred in the cathode was close to four, indicating complete ORR. The max. power density (Pmax) of the single cell with the Co–N–C cathode catalyst demonstrated a high value of 227.7 mWcm−2.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Wang

Hsieh²,

Huang³

et al. 2023

Polymers

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“…Thiourea and its derivatives are widely used in various areas of the physical and life sciences such as microbiology, biochemistry, medicine, chemical technology, and nonlinear dynamics. One example is the thiourea-complexed cobalt(II) ion being used successfully as a cathode catalyst for proton-exchanged membrane fuel cells, and other different derivatives of thiourea (Tu) have been reported to be advantageous materials for corrosion inhibition, anion sensors, chemosensors, and colorimetric detection . Furthermore, some thiourea derivatives have recently been found to be effective antioxidants and to exhibit promising potential as antitumor drugs. , They can also inhibit the infection of various viruses and can serve as effective substances against Gram-positive and -negative bacteria and protozoa …”

Section: Introductionmentioning

confidence: 99%

Compatible Kinetic Model for Quantitative Description of Dual-Clock Behavior of the Complex Thiourea–Iodate Reaction

2023

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The thiourea−iodate reaction has been investigated simultaneously by ultraviolet−visible spectroscopy and high-performance liquid chromatography (HPLC). Absorbance−time traces measured at the isosbestic point of the iodine−triiodide system have revealed a special dual-clock behavior. During the first kinetic stage of the title reaction, iodine suddenly appears only after a well-defined time lag when thiourea is totally consumed due to the rapid thiourea−iodine system giving rise to a substrate-depletive clock reaction. After this delay, iodine in the system starts to build up suddenly to a certain level, where the system remains for quite a while. During this period, hydrolysis of formamidine disulfide as well as the formamidine disulfide−iodine system along with the Dushman reaction and subsequent reactions of the intermediates governs the parallel formation and disappearance of iodine, resulting in a fairly constant absorbance. The kinetic phase mentioned above is then followed by a more slowly increasing sigmoidally shaped profile that is characteristic of autocatalysis-driven clock reactions. HPLC studies have clearly shown that the thiourea dioxide−iodate system is responsible mainly for the latter characteristics. Of course, depending on the initial concentration ratio of the reactants, the absorbance−time curve may level off or reach a maximum followed by a declining phase. With an excess of thiourea, iodine may completely disappear from the solution as a result of the thiourea dioxide−iodine reaction. In the opposite case, with an excess of iodate, the final absorbance reaches a finite value, and at the same time, iodide ion will disappear completely from the solution due to the well-known Dushman (iodide−iodate) reaction. In addition, we have also shown that in the case of the formamidine disulfide− iodine reaction, unexpectedly the triiodide ion is more reactive toward formamidine disulfide than iodine. This feature can readily be interpreted by the enhancement of the rate of formation of the transition complex containing oppositely charged reactants. A 25-step kinetic model is proposed with just 10 fitted parameters to fit the 68 kinetic traces measured in the thiourea−iodate system and the second, but slower, kinetic phase of the thiourea−iodine reaction. The comprehensive kinetic model is constituted in such a way as to remain coherent in quantitatively describing all of the most important characteristics of the formamidine disulfide−iodine, thiourea dioxide−iodine, and thiourea dioxide−iodate systems.

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“…Metal ions, which are the active centers of the SACs, cannot chelate with neat carbon materials due to the shortage of ion-paired electrons that can coordinate with the metal ions before subjecting to calcination. Therefore, similar to the N-containing organic compounds mentioned in the preparation of Pt/C nanoparticles, we intended to polymerize Fe-or Co-ion-chelated amine-containing monomers to enclose and capture the metal ions before calcining to the SAC frameworks [17][18][19]. Eventually, Fe or Co can coordinate with four or less nitroge0n in the carbon matrix (FeNxC or CoNxC), and become the catalyzing active centers [20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Cobalt-Doped Carbon Nitride Frameworks Obtained from Calcined Aromatic Polyimines as Cathode Catalyst of Anion Exchange Membrane Fuel Cells

Hsieh¹,

Chen²,

Wang³

et al. 2022

Membranes

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Cobalt-doped carbon nitride frameworks (CoNC) were prepared from the calcination of Co-chelated aromatic polyimines (APIM) synthesized from stepwise polymerization of p-phenylene diamine (PDA) and o-phthalaldehyde (OPAl) via Schiff base reactions in the presence of cobalt (II) chloride. The Co-chelated APIM (Co-APIM) precursor converted to CoNC after calcination in two-step heating with the second step performed at 100 °C lower than the first one. The CoNCs demonstrated that its Co, N-co-doped carbonaceous framework contained both graphene and carbon nanotube, as characterized by X-ray diffraction pattern, Raman spectra, and TEM micropictures. CoNCs also revealed a significant ORR peak in the current–voltage polarization cycle and a higher O2 reduction current than that of commercial Pt/C in a linear scanning voltage test in O2-saturated KOH(aq). The calculated e-transferred number even reaches 3.94 in KOH(aq) for the CoNC1000A900 cathode catalyst, which has the highest BET surface area of 393.94 m2 g−1. Single cells of anion exchange membrane fuel cells (AEMFCs) are fabricated using different CoNCs as the cathode catalysts, and CoNC1000A900 demonstrates a peak power density of 374.3 compared to the 334.7 mW cm−2 obtained from the single cell using Pt/C as the cathode catalyst.

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Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell

Cited by 9 publications

References 29 publications

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

2,6-Diaminopyridine-Based Polyurea as an ORR Electrocatalyst of an Anion Exchange Membrane Fuel Cell

Compatible Kinetic Model for Quantitative Description of Dual-Clock Behavior of the Complex Thiourea–Iodate Reaction

Cobalt-Doped Carbon Nitride Frameworks Obtained from Calcined Aromatic Polyimines as Cathode Catalyst of Anion Exchange Membrane Fuel Cells

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