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The development of non‐precious metal cathode catalysts for anion exchange membrane fuel cells (AEMFC) is beneficial for achieving a more affordable and sustainable H 2 economy. Herein, we propose a polypyrrole, polythiophene and multi‐walled carbon nanotube‐based composite material (PPy/PTh/MWCNT) for the electrocatalysis of oxygen reduction react...
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... However, challenges remain in the development of facile synthesis methods for amorphous nanomaterials and in investigating the relationship between their structure and activity [21]. To overcome this limitation, metallic oxide-based catalysts are often supported on highly conductive materials, such as polypyrrole (PPy) [22], polythiophene (PTh) [23], or polyaniline (PANI) [24]. These polymers have gained significant attention due to their low cost, convenient synthesis, strong energy storage capacity, and high electrical conductivity [25]. ...
Non-noble-metal-based electrocatalysts possessing high inherent activity toward the oxygen evolution reaction (OER) are highly desired. Considering the synergetic effect of different metal sites and the high conductivity of polyaniline (PANI), here we report polymer-based bimetallic ternary nanocomposite (Fe–Mn@PANI), which is synthesized by in situ polymerization method. Fe–Mn@PANI/NF has shown the best OER activity with lower onset potential (1.46 V vs RHE), low overpotential of 353 mV at 10 mA cm−2, and Tafel slope of 68 mV dec−1. The remarkable outcomes can be attributed to the synergistic effect of the two distinct metals and PANI, which particularly has a unique π-conjugated structure and abundant nitrogen species with lone pairs of electrons providing a consistent flow of ions across entire surface of composite and also improving OH− adsorption capacity which makes it a highly efficient, cost-effective, and stable catalyst with improved performance of the OER.
... Membrane-electrode assemblies (MEA) were prepared using the catalyst-coated gas-diffusion layers (GDL, Sigracet 39 BB) and 195 lL of 3 wt% poly[2,2 0 -(2,2 00 ,4,4 00 ,6 00 -hexamethyl-p-terphenyl-3, 3 00 -diyl)-5,5 0 -bibenzimidazole] (HMT-PMBI) ionomer solution [53,54]. The anode ink preparation and coating of both GDLs was performed according to the previously published procedure [55,56]. The catalyst loadings of 2 mg cm À2 and 0.8 mg Pt-Ru cm À2 were obtained on the cathode and anode electrode, respectively. ...
... The catalyst loadings of 2 mg cm À2 and 0.8 mg Pt-Ru cm À2 were obtained on the cathode and anode electrode, respectively. The catalyst coated GDLs and the AEM were soaked in 3 M KOH solution for the same time period as used in our previous study [55,56]. After soaking in 3 M KOH, the components with silicone gaskets were compiled into a 5 cm 2 cell (Fuel Cell Technologies Inc., USA) using a torque of 9 Nm. ...
... Conformably, the higher ORR activity for D-MN 4 -CNF-IL-A compared to the Co and Fe acetate-based Fe/Co/IL-CNF-800b [48] was observed during the half-cell tests in 0.1 M KOH (Section 3.1). Several other NPMC materials studied in a similar AEMFC setup (Table 6) have recently shown better ORR performance than D-MN 4 -CNF-IL-A despite the rather similar ORR results obtained in 0.1 M KOH in RDE mode [54][55][56]. On the other hand, fluorinated FePc supported on commercially available high-surfacearea carbon showed higher ORR activity in 0.1 M KOH, but lower AEMFC performance compared to D-MN 4 -CNF-IL-A, as reported recently by Friedman et al. [73]. ...
... Currently, the highly active and stable nonnoble metal catalysts for alkaline ORR have been widely studied to decrease the cost of the AEMFCs. Among the studied nonnoble metal catalysts, transition metals and nitrogen-doped carbon (M-N-C, M: Fe, Co, Mn, Ni, etc.) catalysts have received great attention because of their good catalytic activity, ideal stability, and cost-effective scalable synthesis [9][10][11][12][13][14][15][16][17][18][19][20]. Previous researches have reported that the electrocatalytic performance of the M-N-C catalysts follows the order of Fe > Co > Mn > Ni in alkaline electrolytes [21][22][23]. ...
Developing a low-price, high catalytic activity, and strong durability electrocatalyst for alkaline oxygen reduction reaction (ORR) is significantly important for anion exchange membrane fuel cell (AEMFC). Herein, Co and Mn salts were added into ZIF-8 to obtain CoMn-ZIF-Ac-2. Co and Mn embedded in nitrogen-doped microporous carbon (CoMn-N-C-Ac-2-Ts, T = 700 , 800, 900, and 1000°C) were obtained by carbonizing CoMn-ZIF-Ac-2 at various temperature. The influence of various pyrolysis temperature and molar ratios between Co and Mn toward ORR catalytic activity was researched. For CoMn-N-C-Ac-2-Ts, CoMn-N-C-Ac-2-800 had the highest ORR catalytic activity with the half-wave potential of 0.875 V in 0.1 M KOH, only 5 mV lower than that of 20 wt % Pt/C. Besides, high 4e- selectivity, excellent stability (retaining 100% for 20 h at 0.6 V vs. RHE), and methanol tolerance are also exhibited. In addition, CoMn-N-C-Ac-2-800 exhibited better ORR activity than Mn-N-C-Ac-800 and Co-N-C-Ac-800, which was attributed to more Co-N4, more MnIII species, and higher surface area. Moreover, the AEMFC based on the CoMn-N-C-Ac-2-800 cathode catalyst obtained a maximal power density of 291 mW·cm-2, which was 78% of the P max achieved with 20 wt % Pt/C (375 mW·cm-2). The highest ORR performance for CoMn-N-C-Ac-2-800 was contributed by the highest defect degree, the most amounts of Co/Mn-N4 active site, the maximum BET surface area, and micropore structure.
... For AEMFC testing, the membrane-electrode assembly (MEA) was prepared using the catalyst-coated gas-diffusion layers (GDL, Sigracet 39 BB) and AF2-HLE8-10-X (AEMION+ 10 µm, Ionomr Innovations Inc., Canada [43]) anion exchange membrane (AEM). The 3 wt% ionomer solution for anode was prepared by dissolving AP2-INN8-00-X (AEMION+ Powder) in methanol [44]. The anode GDL was coated with the catalyst ink prepared by dispersing 3.35 mg of Pt− Ru/C (50:25:25, Alfa Aesar) in 345 μL of methanol, 98 μL of Milli-Q water and 25 μL of 3 wt% AP2-INN8-00-X solution. ...
... The 3 M KOH solution used for AEM treatment was changed daily [40]. The 5 cm 2 cell (Fuel Cell Technologies Inc., USA) was pressed together according to the previously published protocol [40,44] and employed for the single-cell AEMFC testing using a Greenlight Fuel Cell Test Station (G40 Fuel Cell System, Hydrogenics, Canada). The cell was fed using 1 NLPM gas flow rate at 65 • C with the backpressure set for 200 kPa. ...
Cobalt-, iron- and nitrogen-doped ordered mesoporous carbon (OMC)-based electrocatalysts are prepared, characterized, and used as cathode catalysts in anion-exchange membrane fuel cell (AEMFC). The OMC material is synthesized using a green and simple route via soft-template method and without the usage of harsh chemicals. To study the effect of porous structure of carbon support on the electrocatalytic properties, the OMC material is also mixed either with carbide-derived carbon (CDC) or carbon nanotubes (CNTs). Doping of carbon nanomaterials is done via high-temperature pyrolysis in the presence of cobalt and iron acetate as well as 1,10-phenanthroline. The physico-chemical characterization shows that the preparation of OMC and subsequent doping of nanocarbons has been successful, and the catalysts contain single-atom M-Nx centres. The initial assessment employing the rotating disc electrode method indicates that all three doped catalyst materials exhibit very high electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline media and good stability after 10,000 potential cycles. In AEMFC testing with AEMION+ anion exchange membrane, the prepared cathode catalysts show good performance with CoFe-N-OMC/CNT obtaining the highest peak power density of 336 mW cm–2. Slightly lower AEMFC performance observed for CoFe-N-OMC and CoFe-N-OMC/CDC cathodes indicates that it is influenced by the catalyst's porous structure. It can be concluded that the OMC-based materials are promising cathode catalysts for AEMFC application.
... Besides, many more inorganic materials have been used to modify AEMs, e.g. SiO 2 [14][15][16], ZrO 2 [17][18][19],TiO 2 [20][21][22], carbon nitride [23][24][25], carbon nanotubes [26][27][28] and gaphene [29][30][31]. Recently, carbon quantum dots (CQDs) have been widely used for nanosensors [32][33][34], catalyzers [35][36][37][38][39][40], biomedical field [41][42][43][44][45], batteries [46][47][48], etc., because of small size effects, biocompatibility, and excellent mechanical and optical properties. ...
Low ion conductivity and poor alkali resistance are still the two major obstacles for the applications of anion exchange membranes (AEMs). In this work, the combined strategies of Carbon quantum dots (CQDs) hybrid and cross-linking modification via side-chains designing were employed to prepare organic-inorganic hybrid AEMs. Then, the cross-linked quaternized polysulfone (CQPSf-CQDs) hybrid AEMs by incorporating carbon quantum dots were successfully fabricated. After hybrid and cross-linking, the mechanical properties of CQPSf-CQDs hybrid AEMs were higher than that of the pristine one, reaching 49.4 MPa for the best one. Meanwhile, the existence of CQDs can expand the hydrophilic area in the membrane, which is beneficial to the transport of OH-. The incorporated CQDs interact weakly with cationic groups in the side chains through hydrogen bonds. The simulation results further demonstrated that the introduction of CQDs was beneficial to the construction of hydrophilic and hydrophobic domains, thereby increasing OH- conductivity. In addition, the prepared hybrid membranes own excellent dimensional stabilities and ion transport performances. These preliminary results give us a lot of hopes for further experiments and optimizations for the hybrid AEMs.
A Pt‐free cathode catalyst is necessary for proton‐exchange membrane fuel cell (PEMFC) to enable the widespread use of these environmentally friendly energy conversion devices at affordable price. Herein, a pyrolyzed electrospun carbon nanofibre (CNF) catalyst is prepared embedded with cobalt(II) phthalocyanine and iron(II) phthalocyanine compounds to provide the transition metal N 4 ‐macrocyclic complex‐derived sites (MN X ) possessing better electrocatalytic oxygen reduction reaction (ORR) activity. The physical characterisation showed the nanofibrous structure of catalyst with rough surface texture and considerable amount of N, Fe, and Co. The D−MN 4 −CNF−IL−A catalyst prepared using ionic liquid as a porogen displayed the best electrocatalytic activity for O 2 electroreduction proceeding via 4e ⁻ pathway in 0.5 M H 2 SO 4 electrolyte solution with the ORR onset and half‐wave potential of 0.83 and 0.71 V vs reversible hydrogen electrode (RHE), respectively.
This article details the development of noble-metal free electrocatalytic materials based on Prussian blue analogue (metal–organic-type framework) immobilized on reduced graphene oxide for oxygen reduction reaction in alkaline medium.
