Nitrogen-doped carbide-derived carbon/carbon nanotube composites as cathode catalysts for anion exchange membrane fuel cell application (original) (raw)
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Renewable Energy, 2021
Iron and nitrogen doping of carbon materials is one of the promising pathways towards replacing Pt/C in polymer electrolyte fuel cell cathodes. Here, we show a synthesis method to produce highly active non-precious metal catalysts and study the effect of synthesis parameters on the oxygen reduction reaction (ORR) activity in high-pH conditions. The electrocatalysts are prepared by functionalizing silicon carbide-derived carbon (SiCDC) with 1,10-phenanthroline, iron(II)acetate and, optionally polyvinylpyrrolidone, by ball-milling with ZrO2 in dry or wet conditions, followed by pyrolysis at 800 °C. The catalysts are characterized by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, N2 physisorption and inductively coupled plasma mass spectrometry. By optimizing the ball-milling conditions, we achieved a reduction in the size of SiCDC grains from >1 µm to 200 nm without negatively affecting the
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.
Journal of Power Sources, 2016
In this work, the electroreduction of oxygen on nitrogen-doped graphene and multi-walled carbon nanotube (MWCNT) composite catalysts is investigated. Acid-treated MWCNTs and graphite oxide were doped using biuret, carbohydrazide and semicarbazide hydrochloride as the nitrogen precursors. The reactants were mixed with carbon nanomaterials and pyrolysed in an inert atmosphere at 800 C. Scanning electron microscopy was used to characterise the surface morphology of catalysts and X-ray photoelectron spectroscopy (XPS) was used to determine the surface content of the catalysts. XPS revealed different contents of nitrogen gained by using different nitrogen precursors, which were tied to electrochemical activities observed in this work by using the rotating disk electrode (RDE) method. The catalysts revealed high oxygen reduction reaction (ORR) activity even at low loadings and excellent stability over 1000 potential cycles. This indicates their applicability as cathode materials in alkaline anion exchange membrane fuel cells.
Journal of Power Sources Advances, 2021
A novel and commercially available electrocatalyst is characterised and used as cathode catalyst in an anionexchange membrane fuel cell (AEMFC). The catalyst material is prepared using VariPore™ method by Pajarito Powder, LLC, and as dopants iron and nitrogen are used, making it a mesoporous transition metal-nitrogen-carbon type catalyst. The physico-chemical characterisation shows the success of doping as well as almost completely mesoporous structure (average pore size of approximately 7 nm) with high specific surface area. The initial assessment of the oxygen reduction reaction (ORR) activity by the rotating ring-disc electrode method reveals that the material exhibits a very good electrocatalytic performance in alkaline media having a half-wave potential of 0.89 V. The catalyst material is employed as an anion exchange membrane fuel cell cathode and it shows AEMFC performance as good as that of the Pt-based material. The high ORR electrocatalytic activity of this material is due to the synergy of nitrogen-moieties, namely pyrrolic-N, pyridinic-N and graphitic-N, with iron as well as the highly mesoporous nature.
NiCo–N-doped carbon nanotubes based cathode catalyst for alkaline membrane fuel cell
Renewable Energy, 2020
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ChemElectroChem, 2018
Replacing Pt‐based catalysts with noble‐metal free catalysts for the oxygen reduction reaction (ORR) is one of the most important topics currently in electrocatalysis. Iron‐ and nitrogen‐doped carbon materials have shown great promise in this area. In this work, we demonstrate the remarkable electrocatalytic activity towards the ORR of carbide‐derived carbon (CDC) and multi‐walled carbon nanotube (MWCNT) composite catalysts. The CDC material is synthesized from titanium carbide and doped using 1,10‐phenanthroline and iron (II) acetate. The material is then mixed with MWCNTs and further modified with dicyandiamide (DCDA) and additional iron by using a multi‐step pyrolysis procedure. The morphology, structure, porosity, and elemental composition are then comprehensively studied with scanning electron microscopy, X‐ray photoelectron spectroscopy, N2 physisorption, and inductively coupled plasma mass spectroscopy. The electrocatalytic activity of the catalysts for the ORR is studied usi...
Application of carbon supported NiMo carburized catalyst to fuel cell anode electrocatalyst
Journal of New Materials for …, 2008
Nickel molybdenum oxides mixed with Ketjen carbon (KC) were carburized at temperatures of 823-973 K. The 30 wt% Ni-Mo carbide (NiMoC/KC) catalysts were studied for their anodic electrocatalytic activities based on polarization tests in a single PEFC. Ni25MoC carburized at 873 K exhibited the highest activity when compared to the other Ni compositions and carburization temperatures. The cyclic voltammetry of the working cell indicated that the bimetallic NiMo/KC carbide catalysts exhibited a high activity for the anodic electrooxidation of hydrogen and a significant stability in the fuel cell environment. The activities were due
Journal of Colloid and Interface Science, 2021
Highly active electrocatalysts for electrochemical oxygen reduction reaction (ORR) were prepared by high-temperature pyrolysis from 5-methylresorcinol, Co and/or Fe salts and dicyandiamide, which acts simultaneously as a precursor for reactive carbonitride template and a nitrogen source. The electrocatalytic activity of the catalysts for ORR in alkaline solution was studied using the rotating disc electrode (RDE) method. The bimetallic catalyst containing iron and cobalt (FeCoNC-at) showed excellent stability and remarkable ORR performance, comparable to that of commercial Pt/C (20 wt%). The superior activity was attributed to high surface metal and nitrogen contents. The FeCoNC-at catalyst was further tested in anion exchange membrane fuel cell (AEMFC) with poly-(hexamethyl-p-terphenylbenzimidazolium) (HMT-PMBI) membrane, where a high value of peak power density (P max = 415 mW cm À2) was achieved.
Journal of Physical Chemistry C, 2009
One of the main challenges in the commercialization of low temperature fuel cells is the slow oxygen reduction reaction (ORR) kinetics and the high cost and scarcity of platinum (Pt)-based catalysts. As a result, alternative non-noble electrocatalysts to Pt materials for ORR is needed to realize the practical application of fuel cells. In this study, nitrogen-doped carbon nanotubes (NCNTs) were synthesized as a non-noble electrocatalyst for the ORR using ethylenediamine (EDA-NCNT) and pyridine (Py-NCNT) as different nitrogen precursors by a single-step chemical vapor deposition (CVD) process. The resulting EDA-NCNT has shown similar ORR performance compared to platinum on carbon support in terms of onset and half-wave potentials. Moreover, EDA-NCNT showed superior ORR performance in terms of limiting current density, number of electrons transferred, and H 2 O selectivity. The effects of nitrogen content on ORR performance of NCNT were investigated by comparing EDA-NCNT with Py-NCNT. The ORR performance of Py-NCNT was inferior compared to EDA-NCNT in terms of onset and half-wave potentials, limiting current density, number of electrons transferred, and H 2 O selectivity. Further material characterizations by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy illustrated a higher nitrogen content and more defects in EDA-NCNT compared to that of Py-NCNT which indicates the important role of the nitrogen precursor on nitrogen content and structure of NCNT. By combining the results of ORR activity and material characterization, it is concluded that higher nitrogen content and more defects of NCNT lead to high ORR performance.