NiCo–N-doped carbon nanotubes based cathode catalyst for alkaline membrane fuel cell (original) (raw)
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Applied Catalysis B: Environmental, 2014
The performance of a direct methanol alkaline anion-exchange membrane (Fumatech FAA3) fuel cell with Pt-free nitrogen-doped few-walled carbon nanotubes (N-FWCNT) as the cathode catalyst is compared with a commercial supported Pt catalyst. The ionomer content of the N-FWCNT cathode catalyst layer is therefore optimized and it is shown to be 40 wt% of FAA3. Scanning electron microscopy images of the catalyst layer show that the ionomer forms aggregates with N-FWCNTs probably due to their charged nature and that the catalyst layer structure is remarkably open even with high ionomer contents facilitating the mass transfer of reactants and products to the active sites. With oxygen as the oxidant, the maximum power density obtained with our Pt-free N-FWCNTs (0.78 mW cm −2 ) is slightly higher than with the Pt catalyst (0.72 mW cm −2 ). However, when more practical air is used as the oxidant, the N-FWCNTs (0.73 mW cm −2 ) show clearly superior performance compared to the Pt catalyst (0.18 mW cm −2 ). The lower performance with the Pt catalyst is attributed to the denser electrode layer structure resulting in higher mass transport resistance and to the presence of methanol in the cathode, which poisons the Pt but not the N-FWCNTs.
Development of carbon nanotubes catalyst supported for alkaline fuel cell technology
Journal of Physics: Conference Series, 2019
Study of the development of an activated carbon nanotube catalyst for alkaline fuel cell technology. Through the prepared carbon nanotubes catalyst by an electrochemical deposition technique. Different analytical approaches such as X-ray diffraction (XRD) to determine the structural properties and Scanning Electron Microscope (SEM), were used to characterize, Mesh stainless steel catalyst substrate had an envelope structure and a large surface area. Voltages were also obtained at 1.83 V and current at 3.2 A of alkaline fuel cell. In addition, study the characterization of the electrochemical parameters.
Applied Catalysis B: Environmental, 2020
Nitrogen-doped carbide-derived carbon/carbon nanotube (CDC/CNT) composites were prepared and employed for the first time as a cathode electrocatalyst for the anion exchange membrane fuel cell (AEMFC). The CDC/CNT composites were doped with nitrogen using high temperature pyrolysis in the presence of different nitrogen precursors. In the rotating disk electrode measurements all N-CDC/CNT catalysts showed good electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline solution with the half-wave potential (E 1/2) around-0.25 V vs SCE. Moreover, the materials showed high tolerance to methanol and excellent stability after 10,000 potential cycles with a negative shift in E 1/2 of 10 and 14 mV, respectively. In AEMFC testing employing hexamethyl-p-terphenyl poly(benzimidazolium) (HMT-PMBI) anion exchange membrane, N-CDC/CNT as a cathode catalyst exhibited very good performance with the peak power density of 310 mW cm-2. It can be concluded that the N-CDC/CNT composites are promising cathode catalysts for AEMFCs and alkaline direct methanol fuel cells.
International Journal of Energy Research, 2019
The application of nonprecious metal catalysts, such as iron (Fe) and cobalt (Co) catalyst, to direct liquid fuel cells (DLFCs), especially in direct methanol fuel cells, has been widely investigated. However, the application of such non-Pt catalysts as cathode catalysts in direct formic acid fuel cell (DFAFC) operations has not yet been investigated. This study intends to evaluate the formic acid tolerance of such catalysts in case of oxygen reduction reaction. In addition, we investigate their performances in DFAFC using the Fe-and Co-nitrogen-doped carbon nanotubes (Fe-NCNT and Co-NCNT) as the cathode catalysts and compare these performances with the commercial Pt/C catalyst. Herein, Fe-NCNT and Co-NCNT were synthesized using the conventional method by the pyrolysis of the multiwalled carbon nanotubes, dicyandiamide, and metal salt under the flow of N 2 at 800°C. Both the Fe-NCNT and Co-NCNT catalysts exhibit higher formic acid tolerance when compared with that exhibited by the Pt/C catalyst. Further, single-cell tests with hydrogen-fed polymer electrolyte fuel cell (PEFC) and DFAFC operations were conducted under various operating conditions to compare the performances of the cells while using the prepared catalysts and the conventional Pt/C catalyst. The PEFC performances in both the Fe-NCNT and Co-NCNT catalysts were significantly low (94.9mW cm −2 for Fe-NCNT and 164.0 mW cm −2 for Co-NCNT at 60°C). Regardless, the Co-NCNT catalyst exhibited a maximum power density of 160.7 mW cm −2 in DFAFC operated at 60°C and7-M formic acid. This value is comparable with that for DFAFC with a Pt/C catalyst (128.9mW cm −2) and is considerably higher than that obtained for other DLFCs while using a non-Pt catalyst. Therefore, the usage of a non-Pt metal catalyst as the cathode catalyst is preferable in case of DFAFC.
Electrochemistry Communications, 2010
A new approach to synthesize nitrogen-doped carbon nanotubes (NCNTs) as catalysts for oxygen reduction by treating oxidized CNTs with ammonia is presented. The surface properties and oxygen reduction activities were characterized by cyclic voltammetry, rotating disk electrode and X-ray photoelectron spectroscopy. NCNTs treated at 800°C show improved electrocatalytic activity for oxygen reduction as compared with commercially available Pt/C catalysts.
ACS Catalysis
Recent experimental reports proposed that pyridinic-type sites on the open edges of carbon nanotubes (CNTs) may contribute to the high catalytic activity for oxygen reduction reaction (ORR) on nitrogen-doped CNTs (N-CNTs). Herein, we performed first-principles spin-polarized density functional theory calculations to examine the catalytic steps for ORR and water formation reaction (WFR) on the open edges of N-CNTs. For half-N doping on the open edge of CNTs (HN-CNTs), O2 and OOH can be chemisorbed and partially reduced on the C–N bridge site without an energy barrier. The subsequent WFR for reduced O2/OOH with ambient H+ and additional electrons can be finished without energy barrier for the formation of two H2O molecules. The second H2O molecule needs an energy of 0.49 eV to be desorbed from the catalytic site, which completes an electrocatalytic reaction cycle on the cathode catalyst for hydrogen fuel cells (HFCs). For H-saturated open-edge sites of HN-CNT, ORR and WFR can also be ...
Nitrogen Containing Carbon Catalyst for use in PEM fuel cell cathodes
2006
Fuel cells are an alternative energy source to traditional energy sources, such as combustion engines or batteries. They create energy through the electrochemical reaction between hydrogen and oxygen, leaving water as a byproduct. Therefore as an energy source, fuel cells are very clean, effective, and environmentally friendly, making them advantageous in the long run when compared with most traditional energy sources. There are many classes of fuel cells, but low temperature PEM fuel cells are especially important because they are used in transportation and automotive industries. Although fuel cells have many advantages, they are not currently cost effective to produce. This research explores the creation and implementation of alternative materials that are cheaper, and have better active and conductive properties which will help improve the performance of fuel cells, and make them available for application in daily life. During this study, composites of highly active (but less conductive) and highly conductive (but less active) catalyst were determined to be useful for the making of better materials. The best composite found was one that contained 25% active fibers and a secondary conductive catalyst. In addition, Fe and Co supported by SiO 2 or MgO had high activity and better conductivity than fibers grown from Fe supported by Al 2 O 3 in some cases. No methanol oxidation activity was observed, this is a positive result for methanol fuel cells since methanol would not react with the materials used in the fuel cell. Separation techniques and full fuel cells were studied as well.
Non-platinum cathode catalysts for alkaline membrane fuel cells
Cobalt phthalocyanine Tokuyama membrane Membrane-electrode assembly Alkaline membrane fuel cell a b s t r a c t Hydrogeneoxygen fuel cells using an alkaline anion exchange membrane were prepared and evaluated. Various non-platinum catalyst materials were investigated by fabricating membrane-electrode assemblies (MEAs) using Tokuyama membrane (# A201) and compared with commercial noble metal catalysts. Co and Fe phthalocyanine catalyst materials were synthesized using multi-walled carbon nanotubes (MWCNTs) as support materials. X-ray photoelectron spectroscopic study was conducted in order to examine the surface composition. The electroreduction of oxygen has been investigated on Fe phthalocyanine/MWCNT, Co phthalocyanine/MWCNT and commercial Pt/C catalysts. The oxygen reduction reaction kinetics on these catalyst materials were evaluated using rotating disk electrodes in 0.1 M KOH solution and the current density values were consistently higher for Co phthalocyanine based electrodes compared to Fe phthalocyanine. The fuel cell performance of the MEAs with Co and Fe phthalocyanines and Tanaka Kikinzoku Kogyo Pt/C cathode catalysts were 100, 60 and 120 mW cm À2 using H 2 and O 2 gases.