Synthesis of bimetallic iron ferrite Co0.5Zn0.5Fe2O4 as a superior catalyst for oxygen reduction reaction to replace noble metal catalysts in microbial fuel cell

A low-cost electrochemically active oxygen reduction reaction (ORR) catalyst is obligatory for making microbial fuel cells (MFCs) sustainable and economically viable. In this endeavour, a highly active surface modified ferrite, with Co and Zn bimetal in the ratio of 1:1 (w/w), Co_0.5Zn_0.5Fe₂O₄ was synthesised using simple sol-gel auto combustion method. Physical characterisation methods revealed a successful synthesis of nano-scaled Co_0.5Zn_0.5Fe₂O₄. For determination of ORR kinetics of cathode, using Co_0.5Zn_0.5Fe₂O₄ catalyst, electrochemical studies viz. cyclic voltammetry and electrochemical impedance spectroscopy were conducted, which demonstrated excellent reduction current response with less charge transfer resistance. These electrochemical properties were observed to be comparable with the results obtained for cathode using 10% Pt/C as a catalyst on the cathode. The MFC using Co_0.5Zn_0.5Fe₂O₄ catalysed cathode could produce a maximum power density of 21.3 ± 0.5 W/m³ (176.9 ± 4.2 mW/m²) with a coulombic efficiency of 43.3%, which was found to be substantially higher than MFC using no catalyst on the cathode 1.8 ± 0.2 W/m³ (15.2 ± 1.3 mW/m²). Also, the specific power recovery per unit cost for MFC with Co_0.5Zn_0.5Fe₂O₄ catalysed cathode was found to be 4 times higher as compared to Pt/C based MFC. This exceptionally low-cost cathode catalyst has enough merit to replace costly cathode catalyst, like platinum, for scaling up of the MFCs.     

Higher oxygen vacancy content and hydration capability enabled by magnesium doping for high-activity protonic ceramic fuel cell cathode

Protonic ceramic fuel cells (PCFCs) are promising power generation equipment because of their high efficiency and low operating temperature. However, the sluggish oxidation-reduction reaction (ORR) kinetics of the cathode seriously limits their further development. Here, a low-valent alkaline-earth metal Mg-doped BaCo_0.4Fe_0.4Zr_0.2O_3-δ (BaCo_0.4Fe_0.4Zr_0.1Mg_0.1O_3-δ = BCFZMg0.1) cathode is developed to increase oxygen vacancy concentration and hydration capability of mixed oxygen ion-electron conducting (MIEC) electrode materials. The phase composition, microstructure, and stability in wet air were examined, while the oxygen vacancy, hydration capability, conductivity, and surface species of the materials were investigated. Experimental results demonstrate that the oxygen vacancy concentration, hydration capability, and conductivity are all increased by Mg doping. Consequently, the ORR active sites were expanded to the whole electrode surface, and the electrochemical performance of PCFCs with BCFZMg0.1 cathode was greatly improved (peak power density: >40% increase; polarization resistance: 60–70% decrease). This work provides a new strategy to develop cathodes with high ORR activity for PCFCs by doping Mg into the MIEC perovskite B-site.     

In situ Fenton-enhanced cathodic reaction for sustainable increased electricity generation in microbial fuel cells

This study reports that Fenton's reaction is capable of facilitating cathodic reaction and thus increasing the current output in microbial fuel cells (MFCs). The hydroxyl radicals (OH) produced via Fenton's reaction are demonstrated to be vital to the enhancement of electricity generation in MFCs. In a two-chamber MFC employing expanded polytetrafluoroethylene (e-PTFE) laminated cloth as a separator, the power output is enhanced approximately four times with Fenton's reaction. However, the enhancement lasts only a short time period due to the rapid consumption of Fenton's reagents. To overcome this problem, a Fe@Fe₂O₃/carbon felt (CF) composite cathode is made, which results in a greater and, more importantly, sustainable power output. In the composite cathode, Fe@Fe₂O₃ functions as a controllably releasing Fenton iron reagent and CF functions as an air-fed cathode to electro-generate H₂O₂. This newly developed MFC with a Fenton system can ensure a continuous high power output, and also provides a potential solution to the simultaneous electricity generation and degradation of recalcitrant contaminants.     

Highly efficient and ORR active platinum-scandium alloy-partially exfoliated carbon nanotubes electrocatalyst for Proton Exchange Membrane Fuel Cell

Oxygen reduction reaction (ORR) in Proton Exchange Membrane Fuel Cell (PEMFC) is the most sluggish reaction, which impedes the performance and commercialization of PEMFC. Platinum-based alloys show higher ORR activity than Pt and it is suggested by density functional theory calculations that Pt₃Sc alloy has high stability and higher ORR activity due to filling the metal d-bands and lowers binding energy of the oxygen species respectively. Herein, we report Pt₃Sc alloy nanoparticles (NPs) dispersed over partially exfoliated carbon nanotubes (PECNTs) as a cathode catalyst for single-cell measurements of PEMFC where Pt₃Sc alloy shows a lower binding energy towards oxygen and facilitates ORR with much faster kinetics. The ORR activity of Pt₃Sc/PECNTs electrocatalyst, investigated by cyclic voltammetry, Rotating Disk electrode (RDE) and Rotating Ring Disk electrode (RRDE), shows the higher mass activity and lower H₂O₂ formation than the commercial catalyst Pt/C-TKK. Accelerated Durability Tests (ADT) was performed to evaluate the stability of catalysts in acidic medium. In single-cell measurements, Pt₃Sc/PECNTs cathode catalyst exhibits a power density of 760 mW cm⁻² at 60 °C. Our study gives an important insight into the design of a novel ORR electrocatalyst with an excellent stability and high power density of PEMFC.     

Enhancing oxygen reduction activity of perovskite cathode decorated with core@shell nano catalysts

Highly active catalysts towards oxygen reduction reaction (ORR) with good stability are critical for reduced temperature solid oxide fuel cells (SOFCs). Nano Ag@M_0.2Ce_0.8O_2-δ (M = La, Sm, Pr) catalyst with core@shell structure is in-situ synthesized via a facile hydrothermal method on porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) scaffold as SOFC cathode. The diameter of the silver core is ∼60 nm with a uniform outer shell ∼20 nm in thickness. A dramatic decrease (∼80% at 550 °C) on the interfacial polarization resistance was observed for this catalyst-decorated cathode compared to the pristine one. The durability test demonstrated a relatively stable operation for Ag@Pr_0.2Ce_0.8O_2-δ decorated LSCF cathode. The excellent electrochemical performance of this hybrid electrode with convenient fabrication process presents a new strategy for rational design of SOFC cathode with excellent ORR activity and stability.     

Iron and nitrogen codoped carbon catalyst with excellent stability and methanol tolerance for oxygen reduction reaction

A series of non‐precious metal Fe_xNC electrocatalysts for oxygen reduction reaction (ORR) were successfully synthesized using Fe(NO₃)₃, glucose, and melamine as the Fe, C, and N sources, respectively. The effects of the pyrolysis temperature and Fe/N contents on the catalytic performances are comprehensively investigated. Electrochemical results reveal that among the Fe_xNC catalysts, Fe_1.5NC‐900‐2 pyrolyzed at 900°C with the mass ratio of FeC to melamine being 1:10 proves the highest catalytic performance. The half‐wave potential (E_1/2) of ORR was 821 mV (vs reversible hydrogen electrode (RHE)) and only 36 mV lower than that on commercial Pt/C catalyst (857 mV). More importantly, Fe_1.5NC‐900‐2 catalyst shows excellent stability and methanol tolerance. After 1000 sequential cycles, the E_1/2 on Pt/C catalyst shifts negatively by approximately 60 mV, while for Fe_1.5NC‐900‐2 catalyst, this shift is only 28 mV although the number of sequential cycles is increased to 8000. In the presence of methanol, the current decay in the chronoamperometric response at 1000 seconds is only 8% and also much lower than that on Pt/C catalyst (46%). The high catalytic performances arise from the abundant Fe₃N active sites embedded in the carbon matrix of the Fe_xNC catalysts. These findings can be used to discuss the catalytic mechanism of ORR on the Fe_xNC catalysts and design the nonprecious metal carbon‐based electrocatalysts for ORR.     

Iron carbide and iron phosphide embedded N-doped porous carbon derived from biomass as oxygen reduction reaction catalyst for microbial fuel cell

The splendid activity of oxygen reduction reaction (ORR) catalyst can greatly promote the power generation of air cathode microbial fuel cell (AC-MFC). Here, benefiting from the rich P element in radish, Fe₃C and Fe₂P incorporated N-doped porous carbon (Fe₃C/Fe₂P@NC-N₄Fe₂) are prepared with the assistance of NH₄Cl through carbothermal reduction method without adding P resources. As expected, Fe₃C/Fe₂P@NC-N₄Fe₂ possesses excellent ORR performance, in which Fe₃C and Fe₂P furnish abundant ORR active sites and the porous structure in N-doped carbon matrix can facilitate mass transfer. Moreover, the AC-MFC assembled with Fe₃C/Fe₂P@NC-N₄Fe₂ as cathodic ORR catalyst exhibits superior power output performance with the maximum power density of 948.9 mW m^?2, which is 1.03 times of that of 20 wt% Pt/C catalyst. Therefore, Fe₃C/Fe₂P@NC-N₄Fe₂ should be a viable ORR catalyst to replace Pt/C catalyst in the application in AC-MFC.     

Property evaluation of Sm1‐xSrxFe0.7Cr0.3O3‐δ perovskites as cathodes for intermediate temperature solid oxide fuel cells

Perovskite‐type (ABO₃) complex oxides of Sm_1‐xSr_xFe_0.7Cr_0.3O_3‐δ (x = 0.5‐0.7) series were prepared by a glycine‐nitrate combustion process. The crystal structure, oxygen nonstoichiometry, electrical conducting, thermal expansion, and electrocatalytic properties of Sm_1‐xSr_xFe_0.7Cr_0.3O_3‐δ perovskites were inspected in view of their use as cathode materials for intermediate temperature solid oxide fuel cells (IT‐SOFCs). Changing the content of Sm³⁺ at the A‐site was demonstrated to be effective in tuning the structure and properties. The variation of the various properties with Sm³⁺ content was explained in relation to the corresponding evolution of the crystal structure and oxygen nonstoichiometry. Sm_0.3Sr_0.7Fe_0.7Cr_0.3O_3‐δ (x = 0.7) was determined to be the optimal composition in the Sm_1‐xSr_xFe_0.7Cr_0.3O_3‐δ series based on a trade‐off between the thermal expansion and electrocatalytic properties. Sm_0.3Sr_0.7Fe_0.7Cr_0.3O_3‐δ ceramic specimen exhibited an electrical conductivity of approximately 40 S·cm^?1 at 800°C and a thermal expansion coefficient of 14.1 × 10^?6 K^?1 averaged in the temperature range from 40°C to 1000°C. At 800°C in air, Sm_0.3Sr_0.7Fe_0.7Cr_0.3O_3‐δ electrode showed a cathodic polarization resistance of 0.19 Ω·cm², a cathodic overpotential of 30 mV at current density of 200 mA·cm^?2, and an exchange current density of 257 mA·cm^?2. It is suggested that Sm_0.3Sr_0.7Fe_0.7Cr_0.3O_3‐δ is a potential candidate material for cathode of IT‐SOFCs in light of its overall properties.     

Fe2O3-encapsulated and Fe-Nx-containing hierarchical porous carbon spheres as efficient electrocatalyst for oxygen reduction reaction

It is highly desirable to develop high-efficiency non-precious electrocatalysts toward oxygen reduction reaction (ORR). In this work, Fe₂O₃-encapsulated and Fe-Nx-containing porous carbon spheres (Fe₂O₃/N-MCCS) with unique multi-cage structures and high specific surface area (1360 m² g^?1) are fabricated. The unique porous structure of Fe₂O₃/N-MCCS ensures fast transportation of oxygen during ORR. The combined effect of Fe₂O₃ nanoparticles and Fe-Nx configurations endows Fe₂O₃/N-MCCS (E_1/2 = 0.837 V vs. RHE) with superior ORR activity and methanol tolerance to Pt/C. And, Fe₂O₃/N-MCCS exhibits better stability than nitrogen-modified carbon. The characterization results of Fe₂O₃/N-MCCS after long-term test reveals its excellent structural stability. Impressively, zinc-air battery based on Fe₂O₃/N-MCCS showed a peak power density of 132.4 mW cm^?2 and a specific capacity of 797 mAh g^?1, respectively.     

Boosting electrocatalytic performance of Ruddlesden-Popper type Fe-based cathode catalysts by La and Ni co-doping for solid oxide fuel cells

Exploring advanced electrode materials with high electrochemical performance and sufficient durability is crucial to the commercialization of solid oxide fuel cells (SOFCs). Herein, a Ruddlesden-Popper Sr_2·9La_0·1Fe_1·9Ni_0·1O_7?δ (SLFN) oxide is systematically evaluated as efficient oxygen electrode material. La and Ni co-doping strategy demonstrates improved oxygen desorption ability and promoted electrochemical activity of pristine Sr₃Fe₂O_7?δ (SF) toward oxygen reduction react (ORR). Further, the ORR process of the SLFN electrode is probed by electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) technique. The button cell with the SLFN cathode delivers a peak power density of 1.01 W cm^?2 at 700 °C, along with desirable stability over a period of 60 h. This study offers a feasible strategy for developing Ruddlesden-Popper type cathode candidates for SOFCs.     

Power generation using polyaniline/multi‐walled carbon nanotubes as an alternative cathode catalyst in microbial fuel cells

Optimization of the cathode catalyst is critical to the study of microbial fuel cells (MFCs). By using the open circuit voltage and power density as evaluation standards, this study focused on the use of polyaniline (PANI)/multi‐walled carbon nanotube (MWNT) composites as cathode catalysts for the replacement of platinum (Pt) in an air‐cathode MFC, which was fed with synthetic wastewater. Scanning electron microscopy and linear scan voltammogram methods were used to evaluate the morphology and electrocatalytic activity of cathodes. A maximum power density of 476 mW/m² was obtained with a 75% wt PANI/MWNT composite cathode, which was higher than the maximum power density of 367 mW/m² obtained with a pure MWNT cathode but lower than the maximum power density of 541 mW/m² obtained with a Pt/C cathode. Thus, the use of PANI/MWNT composites may be a suitable alternative to a Pt/C catalyst in MFCs. PANI/MWNT composites were initially used as cathodic catalysts to replace Pt/C catalysts, which enhanced the power generation of MFCs and substantially reduced their cost. Copyright © 2014 John Wiley & Sons, Ltd.     

High performance yttria-stabilized zirconia based intermediate temperature solid oxide fuel cells with double nano layer composite cathode

A composite double layer cathode of La_0.6Sr_0.4Co_0.8Fe_0.2O_3?δ/La_0.8Sr_0.2FeO_3?δ (LSCF/LSF) was successfully fabricated by infiltration method to accelerate the sluggish oxygen reduction reaction (ORR) processes. In this composite cathode, both LSF and LSCF layers are uniformly distributed on Yttria-stabilized Zirconia (YSZ) scaffold by optimizing the infiltrating solution components. LSF serves as a protective layer between LSCF and YSZ. The introduction of the LSCF exterior layer has greatly improved cell performance compared with the cell with sole LSF cathode. At 600 °C, the maximum power density of the cell with LSCF/LSF/YSZ composite cathode reaches up to 0.559 W cm^?2. The evolution of the cathode polarization resistance verifies that the ORR activity has been greatly enhanced. Therefore, the results indicate that the high cell performance at intermediate temperatures can be obtained by adopting the LSCF cathode into YSZ-based SOFCs using protective layer and that the infiltration method is a practical way for constructing electrode.     

Enhancing oxygen reduction activity and CO2-tolerance of A-site-deficient BaCo0.7Fe0.3O3-δ cathode by surface-decoration with Pr6O11 particles

Sluggish oxygen reduction reaction (ORR) activity and poor CO₂-tolerance has been the long-standing limitations for the application of alkaline earth metal oxide cathode for solid oxide fuel cells (SOFCs). Here we report this situation can be ameliorated with a composite cathode based on Ba_0.9Co_0.7Fe_0.3O_3-δ (B90CF) by surface-decorated Pr₆O₁₁ (PO) particles. A halved polarization resistance is obtained by B90CF-15PO (PO of 15 wt%) cathode (0.033 Ω cm² at 700 °C) compared to blank B90CF, suggesting boosted oxygen reduction reaction activity owing to the accelerated oxygen surface exchange kinetics introduced by PO particles. PO protective layer also brings up desirable CO₂-tolerance for B90CF cathode due to the more stable fluorite cubic structure of PO and higher acidity of Pr³⁺/Pr⁴⁺ than Ba²⁺_, which ensures the stable operation of cells. This work demonstrates the positive potential of surface-decoration with PO in developing cathodes with high performance and CO₂-tolerance.     

Enhancing oxygen reduction reaction activity of perovskite oxides cathode for solid oxide fuel cells using a novel anion doping strategy

Possessing a high oxygen reduction reaction (ORR) activity is one of the most important prerequisites for the cathode to ensure an efficient solid oxide fuel cell. Herein, a highly active cathode is developed by doping the fluorine anion in anion sites of perovskite oxides (ABO₃). The electrocatalytic activities of three different cathode samples including the original perovskite La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF), the doped La_0.6Sr_0.4Co_0.2Fe_0.8O_2.95-δF_0.05 (LSCFF0.05) and La_0.6Sr_0.4Co_0.2Fe_0.8O_2.9-δF_0.1 (LSCFF0.1) are comparatively investigated. The fluorine doped perovskites reveal higher electrochemical performance than the original perovskite. Based on three cathodes of LSCF, LSCFF0.05 and LSCFF0.1 operated at 850 °C, the measured area specific resistance was 0.018, 0.017 and 0.91 Ω cm², respectively; and the respective maximum power density of the single fuel cell using the 9-μm-thick YSZ electrolyte was 754, 1005, and 737 mW cm^?2. Such performance results vividly indicate that, the obtained perovskite oxyfluoride by doping an optimum amount of F ions can efficiently improve ORR activity and thus is a feasible strategy to develop cathode for high-performance solid oxide fuel cells.     

Polypyrrole/carbon black composite as a novel oxygen reduction catalyst for microbial fuel cells

A polypyrrole/carbon black (Ppy/C) composite has been employed as an electrocatalyst for the oxygen reduction reaction (ORR) in an air-cathode microbial fuel cell (MFC). The electrocatalytic activity of the Ppy/C is evaluated toward the oxygen reduction using cyclic voltammogram and linear sweep voltammogram methods. In comparison with that at the carbon black electrode, the peak potential of the ORR at the Pp/C electrode shifts by approximate 260 mV towards positive potential, demonstrating the electrocatalytic activity of Ppy toward ORR. Additionally, the results of the MFC experiments show that the Ppy/C is well suitable to fully substitute the traditional cathode materials in MFCs. The maximum power density of 401.8 mW m⁻² obtained from the MFC with a Ppy/C cathode is higher than that of 90.9 mW m⁻² with a carbon black cathode and 336.6 mW m⁻² with a non-pyrolysed FePc cathode. Although the power output with a Ppy/C cathode is lower than that with a commercial Pt cathode, the power per cost of a Ppy/C cathode is 15 times greater than that of a Pt cathode. Thus, the Ppy/C can be a good alternative to Pt in MFCs due to the economic advantage.     

Manganese dioxide-coated carbon nanotubes as an improved cathodic catalyst for oxygen reduction in a microbial fuel cell

To develop an efficient and cost-effective cathodic electrocatalyst for microbial fuel cells (MFCs), carbon nanotubes (CNTs) coated with manganese dioxide using an in situ hydrothermal method (in situ MnO₂/CNTs) have been investigated for electrochemical oxygen reduction reaction (ORR). Examination by transmission electron microscopy shows that MnO₂ is sufficiently and uniformly dispersed over the surfaces of the CNTs. Using linear sweep voltammetry, we determine that the in situ MnO₂/CNTs are a better catalyst for the ORR than CNTs that are simply mechanically mixed with MnO₂ powder, suggesting that the surface coating of MnO₂ onto CNTs enhances their catalytic activity. Additionally, a maximum power density of 210 mW m⁻² produced from the MFC with in situ MnO₂/CNTs cathode is 2.3 times of that produced from the MFC using mechanically mixed MnO₂/CNTs (93 mW m⁻²), and comparable to that of the MFC with a conventional Pt/C cathode (229 mW m⁻²). Electrochemical impedance spectroscopy analysis indicates that the uniform surface dispersion of MnO₂ on the CNTs enhanced electron transfer of the ORR, resulting in higher MFC power output. The results of this study demonstrate that CNTs are an ideal catalyst support for MnO₂ and that in situ MnO₂/CNTs offer a good alternative to Pt/C for practical MFC applications.     

Development and application of vanadium oxide/polyaniline composite as a novel cathode catalyst in microbial fuel cell

Polyaniline (Pani), vanadium oxide (V₂O₅), and Pani/V₂O₅ nanocomposite were fabricated and applied as a cathode catalyst in Microbial Fuel Cell (MFC) as an alternative to Pt (Platinum), which is a commonly used expensive cathode catalyst. The cathode catalysts were characterized using Cyclic Voltammetry and Linear Sweep Voltammetry to determine their oxygen reduction activity; furthermore, their structures were observed by X‐ray Diffraction, X‐ray Photoelectron Spectroscopy, Brunauer–Emmett–Teller, and Field‐Emission Scanning Electron Microscopy. The results showed that Pani/V₂O₅ produced a power density of 79.26 mW/m², which is higher than V₂O₅ by 65.31 mW/m² and Pani by 42.4 mW/m². Furthermore, the Coulombic Efficiency of the system using Pani/V₂O₅ (16%) was higher than V₂O₅ and Pani by 9.2 and 5.5%, respectively. Pani–V₂O₅ also produced approximately 10% more power than Pt, the best and most common cathode catalyst. It declares that Pani–V₂O₅ can be a suitable alternative for application in a MFC system. Copyright © 2013 John Wiley & Sons, Ltd.     

Enhancing sustainable bioelectricity generation using facile synthesis of nanostructures of bimetallic Co–Ni at the combined support of halloysite nanotubes and reduced graphene oxide as novel oxygen reduction reaction electrocatalyst in single-chambered microbial fuel cells

The present study aims to utilize the high surface area of the nanotube structure of halloysite (HNTs), an aluminosilicate clay, and conductivity of reduced graphene oxide (rGO) as support material for the deposition of nickel (Ni) and cobalt (Co) nanoparticles. With that aim, a novel bimetallic cathode electrocatalyst, Co–Ni @ HNTs-rGO (Catalyst H₃), is developed. This catalyst is characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopy (TEM). Catalyst H₃ demonstrates outstanding oxygen reduction reaction (ORR) activity, electrochemical stability, electrocatalytic performance, and lowest resistance in comparison to the other developed catalysts and conventional Pt/C. Catalyst H₃ is used in single-chambered MFCs (microbial fuel cells), where the anode is filled with molasses-laden wastewater. The attained maximum power density in MFC (catalyst H₃) is 455 ± 9 mW/m², which is higher than other catalysts. All the results indicate towards its potential use in MFC application.     

Fe2O3 nanoparticles immobilized on N and S codoped C as an efficient multifunctional catalyst for oxygen reduction reaction and overall water electrolysis

Currently, multifunctional electrocatalysts with superior performance are very vital for developing various clean and regenerated energy systems. Herein, an effective multifunctional electrocatalyst comprising Fe₂O₃ nanoparticles immobilized on N and S codoped C has been synthesized via heat-treatment of Fe(II) complex at 800 °C (denoted as Fe₂O₃/NS-C-800). Favorable features including the introduction of maghemite nanoparticles, N/S-codoping effect, and close contact between the Fe₂O₃ nanoparticles and NS-C ender the Fe₂O₃/NS-C-800 with high multifunctional catalytic performance. The onset potential (0.97 V) and half-wave potential (0.81 V) of the Fe₂O₃/NS-C-800 towards oxygen reduction reaction (ORR) are comparable to Pt/C (0.99 and 0.82 V). The Fe₂O₃/NS-C-800 also exhibits high oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity with low OER and HER overpotentials of 0.37 and −0.27 V at 10 mA cm⁻², respectively. In addition, higher ORR, OER and HER stabilities than Pt/C are observed for the Fe₂O₃/NS-C-800. More importantly, the assembled water electrolyzer using the Fe₂O₃/NS-C-800 as the anode and cathode exhibits a high stability at a water electrolysis current density of 10 mA cm⁻². The present study offers a new promising non-noble multifunctional catalyst for future application in renewable energy technologies.     

High‐performance and robust operation of anode‐supported solid oxide fuel cells in mixed‐gas atmosphere

We demonstrate the high‐performance and robust operation of anode‐supported solid oxide fuel cells under a mixed‐gas atmosphere applying a novel cell structure and characterization method, useful for minimizing the conventional problems of mixed‐gas operation with anode‐supported solid oxide fuel cells. To achieve the exothermic methane (CH₄) partial oxidation and sufficient difference in oxygen partial pressure even in mixed‐gas mode, a composite of metallic rhodium and cerium dioxide (CeO₂) was chosen as the optimized reforming and oxygen barrier layer after the comprehensive catalytic experiment. We also obtained increased cell operation reliability through the combination of anode pre‐reduction, an optimized material system, and a customized characterization jig (including cathode‐ahead layout and impinging jet flow). According to the cell test at 600°C under a feeding gas of CH₄ and O₂, an open‐circuit voltage and maximum power density of 0.916 V and 0.422 W/cm², respectively, were successfully achieved. Copyright © 2015 John Wiley & Sons, Ltd.