bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Three-Dimensional, Multiphysics Model of An Alkaline Electrolyzer
Authors: Martinho Diogo Loureiro , Berning Torsten , Abdollahzadehsangroudi Mohammadmahdi , Rasmussen Anders Rønne , Hærvig Jakob , Araya Samuel Simon 
Published: February 2024

During the previous years, increasing awareness of the detrimental effects of greenhouse gas emissions along with the need to supply an increasing world population with electricity has given rise to investments in the field of green energy technology. In particular, research and development has focused on the production of “green hydrogen” which can be used as a source for a sustainable energy system. Green hydrogen can be made from water electrolysis provided the electricity stems from a renewable energy source. Among the different types of water electrolysers, the alkaline electrolyzer cell (AEC) is the most mature technology. Among its advantages compared to other technologies are the low capital expenditure and the simplicity of the system with proven components. However, the detailed heat and mass transfer mechanisms that occur in an AEC are far from completely understood. It is expected that further improvements of the technology and reduction in cost can be attained through a fundamental understanding of above-mentioned phenomena.
In order to better understand the phenomena and the physics of such system, a numerical model is developed in this project. Using ANSYS Fluent 2021 R1, an isothermal, single phase, three-dimensional model is developed to replicate the phenomena in a small single cell. Equations such as Butler-Volmer and Nernst Equation are considered to describe the electrochemical part of the system. A simplified Nernst-Planck equation is also modelled to account with the diffusion and migration of charged species (in this case, the ion OH-). The flow is considered laminar, and the species conservation equation are written to solve the molar concentration of each species. The porosity of the electrodes is changed along the simulations to study its influence on the performance of the electrolyzer. Also, the initial concentration of the species is changed in order to evaluate its effect on the output of the system.
First results suggest that the polarization curve acquired shows a strong consistency with prior experimental findings and outcomes from other simulation models.

Figure 1
Non-Precious Hydrogen Oxidation Catalysts for Anion Exchange Membrane Fuel Cells
Authors: Amigues Simon , Bibent Nicolas , Gervex Arsène , Khan Anastassiya , Zitolo Andrea , Gasmi Amir , Chattot Raphael , Dubau Laetitia , Maillard Frederic , Jaouen Frederic 
Published: February 2024

Green hydrogen as an energy carrier has the potential to dramatically reduce our greenhouse gas emissions and meet the net-zero emissions targets set by the Paris Agreement countries by 2050. This hydrogen can be produced by electrolysis using water and renewable electricity, and be converted into electricity on demand in a fuel cell. Proton exchange membrane fuel cells (PEMFC) are already commercialized, but due to their acidic environment, these devices require precious metal catalysts, in particular platinum, which is an obstacle to their large-scale deployment. In contrast, anion exchange membrane fuel cells (AEMFCs) operate at high pH, facilitating the use of cost-effective and sustainable precious metal free catalysts.
To catalyze the hydrogen oxidation reaction (HOR) in alkaline media, nickel has shown interesting performances to replace precious metal catalysts at the anode of AEMFCs [1]. In order to improve the intrinsic activity of nickel-based materials and reach the performance of precious metals catalysts, two approaches are studied in the literature: optimization of intrinsic properties by alloying Ni with other earth abundant elements, or core@shell nanostructuration of Ni by a protective carbon shell. We are focused on this second approach through the mechanochemical synthesis of a nickel-based Metal-Organic Framework (MOF) from a Ni2+ salt and BTC (1,3,5-benzenetricarboxylic acid), followed by pyrolysis under different atmospheres (Figure 1.a). As already shown in the literature [2], there is a significant effect of the pyrolysis atmospheres (NH3, H2, N2, in various ratios) on the electrochemical performance of the catalysts (Figure 1.b). In this study, we employed ex situ and operando studies approaches to investigate the influence of these different atmospheres on the nanoparticles structuration and to relate them to the electrochemical performances obtained.
Our Ni-based anode materials were characterized by X-ray diffraction, electron microscopy, nitrogen adsorption, and electrochemical techniques, including AEMFC tests. Furthermore, the transformation of the MOF into an active catalyst was followed with in-situ X-ray absorption spectroscopy.
[1] Zhao, J. Chen, W. Sun, H. Pan, «Non-Platinum Group Metal Electrocatalysts toward Efficient Hydrogen Oxidation Reaction», Adv. Funct. Mater., vol. 31, no 20, 2021, p. 2010633.
[2] Ni et al., « An efficient nickel hydrogen oxidation catalyst for hydroxide exchange membrane fuel cells », Nat. Mater., vol. 21, no 7, 2022, p. 804.

Figure 1
The Positive Effects of Carbon-Coating Layers on Protecting the Nanoparticle Towards Poisoning Ions or Gases
Authors: Doan Huong , Sgarbi Ricardo , Labarde Quentin , Chatenet Marian 
Published: February 2024

Recently, the research that explores the positive effects of carbon-coating nanoparticles to fight the severe oxidation/corrosion in Alkaline fuel cell (AFC), Proton-exchange membrane fuel cell (PEMFC) or water electrolyzer is well-recognized, since the carbon layers can extend the catalyst’s durability towards hydrogen oxidation/evolution reactions (HOR, HER) and oxygen evolution/reduction reactions (OER, ORR). Especially for the reactions in alkaline pH, with the graphite coating, the Ni nanoparticles in both HOR and HER can resist passivation and hydride poisoning. [1,2] Similarly, in the same alkaline conditions, the amorphous carbon coating slows down the degradation of Pd catalysts.[3] Moreover, the coating can block big ions such as halide, thus benefiting Pt group metals from resisting halide adsorption, that eventually prevents the dissolution of metal.[4,5]
In this work, we examined the gas poisoning effects on coated catalysts. For example, we synthesized carbon-coated Pd-Ni nanoparticles, supported on Vulcan carbon and studied its electrochemical response in 0.1M KOH at room temperature and its tolerance towards CO gas. As a result, Pd-Ni coated had better resistance to passivation compared to the non-coated Pd-Ni catalyst. It also showed that the thickness of the carbon coating layers was sufficient to block the CO absorption in RDE condition initially (Figure 1, black solid line). Only after 150 cycles of accelerated stress test in Ar (AST-Ar, using potential stepping between 0.1 and 1.23 V vs. RHE with a pulse of 3 s at each potential in Ar-saturated electrolyte, 6s/cycles), the passivation that occurred at high potential could cause a small portion of Pd to be “exposed” and adsorb CO (Figure 1, red solid line). After another 150 cycles of AST-Ar (AST 300), more Pd was exposed to CO adsorption but not fully. This proves the carbon-coating layers can protect the nanoparticles from poison contaminant gas such as NOx, SOx, CO, or the COx-like species. Both AFC and PEMFC systems can benefit from this type of catalyst to operate extensively without losing catalytic activity to passivation or pollution issues.

References

[1] Gao, Y. et al. ACS Appl. Mater. Interfaces
2020, 12 (28), 31575–31581.
[2] Doan, H. et al.
J. Electrochem. Soc. 2021 168 084501
[3]Sgarbi, R., Doan, H. et al.
Electrocatalysis
2022.
[4] Lin, G. et al.
J. Electrochem. Soc. 2016, 163 (1), A5049–A5056.
[5] Mukerjee, S., Doan ,H. et al. - US Patent 10,784,518, 2020

Figure 1
Anion Exchange Membrane Using Fused Expanded Pyridinium As Their Cationic Unit
Authors: Fujigaya Tsuyohiko , Motoishi Yuki , Kim Chaerin , Tanaka Naoki 
Published: February 2024

Ion conductivity is expressed as a function of the Faraday constant, ion concentration, and mobility. Thus, an increase in both ion concentration and mobility is crucial for increasing the ion conductivity. Ion mobility reflects ionic motion in the restricted area of ion conduction channels. The general approach to expand ion conduction channels in AEM is to introduce a large number of ionic groups, i.e., to increase ion-exchange capacity (IEC). Because the increase of IEC also increase ion concentration, increase of IEC have been major strategy for increasing ion conductivity. However, this approach causes softening of the AEM because high IEC involves large amount of water uptake (WU).
On the other hand, the ion concentration in AEM is also affected by the dissociation constant of the ionic groups. However, conventional ionic groups in AEMs, such as ammonium cations, suffer from a low dissociation constant that leads to low ion conduction in AEM. Previously, we found that a fused expanded pyridinium cation (FEP) having a delocalized positive charge showed high dissociation of OH– owing to the weak interaction between the soft acid (FEP) and the hard base (OH–) which can be explained based on the Pearson Hard Soft Acid Base (HSAB) principle. As the result, AEM with FEP unit exhibited excellent ion conductivity of 123.4 ±13.3 mS cm–1 at 80 °C with very low IEC (0.77 mmol g-1).
Recently, we synthesized alkylated fused expanded pyridinium (CxFEP) with alkyl chain lengths (x) of 0, 6, 12, and 18 and introduced into polymers as side chains for AEM applications. FEP is characterized by a large π cation that offers weak electrostatic interactions with anions such as hydroxide (OH–) ions and therefore leads to high OH– conductivity in AEM. CxFEP shows synergetic effect between the π-π interactions of FEP and van der Waals interactions of the alkyl chains and forms a strong assembly, particularly for C6FEP. On the other hand, when CxFEP was introduced into the polymers, C12FEP formed an ordered stacking assembly in the films, whereas the other polymers with shorter (C0 and C6) and longer (C18) alkyl chains exhibited no such ordered structure. For the AEM, all the polymers showed higher ion conductivities than that of commercial ammonium-based AEM, even with their low ion exchange capacities (IEC), probably because of their characteristic weak interactions between the FEP cation and OH–. In particular, the AEM with C12FEP showed the highest ion conductivity of 143.3 ± 27.3 mS cm-1 even with a very low IEC of 0.41 mmol g-1. In addition to the high ion dissociation of FEP, the molecular assembly of FEP provides ionic conduction paths. This study demonstrates the importance of high ion dissociation and formation of a conduction pathway for AEM with high conductivity.
Unveiling the Impact of Carbon Corrosion on the Degradation of Fe-N-C Catalyst Layers in Alkaline Media
Authors: Ku YuPing , Kumar Kavita , Khalakhan Ivan , Hutzler Andreas , Götz Carina , Lloret Segura Vicent , Ehelebe Konrad , Mayrhofer Karl J. J. , Thiele Simon , Boehm Thomas , Cherevko Serhiy 
Published: February 2024

One of the most promising candidates to replace platinum group metal catalysts for oxygen reduction reaction (ORR) in fuel cells (FCs) is the sub-class of iron-nitrogen-carbon (Fe-N-C) catalysts. However, Fe-N-C materials considerably suffer from varied degradation mechanisms. [1-2] Compared to FC operating conditions, start/stop events where the cathodes experience anodic potential may be more damaging due to the carbon corrosion phenomenon. [3] The correlation between carbon corrosion and Fe dissolution rates has been reported in aqueous model systems in acidic media. [3] However, different carbon corrosion mechanisms are reported for acidic and alkaline media. [4] While anion-exchange membrane FCs (AEMFCs) have gained increased attention, studies on the effects of carbon corrosion on realistic AEMFC Fe-N-C catalyst layers are still missing.
In this work, using a gas diffusion electrode (GDE) half-cell coupled with inductively coupled plasma mass spectrometry (ICP-MS), [5] we observed that the rate of Fe loss significantly accelerates with rising potential (E > 1.0 VRHE), commonly experienced during the start/stop events. Increased temperature intensifies the rate of Fe leaching during carbon corrosion (see Figure 1), while the gas atmosphere (Ar or O2) shows a negligible influence. On the contrary, the subsequent Fe deposition and the drop of ORR activity depend on the presence of O2 and the varied temperature. Combining in situ and post-mortem analyses, we report how carbon corrosion in alkaline media degrades Fe-N-C catalyst layers in various atmospheres and at different temperatures. These insights can contribute to rational designs of AEMFCs' start/stop protocol and more robust Fe-N-C materials.

Figure 1. Fe-N-C demetallation during anodic potential holds (1.0 - 1.5 VRHE) in O2-saturated alkaline (0.1 M NaOH) environment at 22 ± 2 and 62 ± 2 ℃. (A) Potential profile. (B) The Fe dissolution rate normalized to catalyst loading.

References:

[1] Adabi, Horie, et al. Nat. Energy., 2021, 6.8: 834-843.
[2] Speck, Florian D., et al. JACS Au, 2021, 1.8: 1086-1100.
[3] Choi, Chang Hyuck, et al. Angew.
Chem. Int. Ed., 2015, 54.43: 12753-12757.
[4] Yi, Youngmi, et al. Catal. Today, 2017, 295: 32-40.
[5] Ku, Yu-Ping, et al. J. Am. Chem. Soc., 2022, 144.22: 9753-9763.

Figure 1
Manganese and Nitrogen Doped Biomass-Based Activated Carbons As Electrocatalysts for Oxygen Reduction and Water Splitting
Authors: Tamasauskaite-Tamasiunaite Loreta , Upskuviene Daina , Balciunaite Aldona , Simkunaite Dijana , Jasulaitiene Vitalija , Niaura Gediminas , Drabavicius Audrius , Vaičiūnienė Jūratė , Volperts Aleksandrs , Plavniece Ance , Dobele Galina , Zhurinsh Aivars , Colmenares-Rausseo Luis Cesar , Kvello Jannicke , Kaare Kätlin , Kruusenberg Ivar 
Published: February 2024

In this study, an efficient manganese (Mn) and nitrogen (N) co-doped carbon materials were prepared using the three raw materials, namely alder charcoal (Mn-N-CAC), hydrothermally carbonised birch wood (Mn-N-CW), and black liquor (Mn-N-CBL). At first, biomass-based activated carbon materials were synthesized. Mn and N were co-doped in one step using the reaction mixture containing Mn2+ ions source, activated carbon material, and dicyandiamide (DCDA) in dimethylformamide (DMF). DMF was evaporated and the mixture was treated for 60 min at a temperature of 800 ºC. The specific surface area, morphology, structure, and composition of Mn-N-C were determined using BET, TEM, XPS, Raman, XRD, and ICP-OES. Activity of resulted Mn-N-C materials was evaluated for oxygen reduction (ORR) as well as for hydrogen and oxygen evolution (HER and OER) using linear-sweep voltammetry (LSV) with a rotating disk electrode (RDE) in alkaline media.
It was found that all Mn-N-C materials had a high specific surface area in the range of approximately of 1800 to 2200 m2 g-1 but the Mn-N-CBL presented a higher contribution of the mesopores in comaparison to Mn-N-CAC and Mn-N-CW which are similar. All synthesized Mn-N-C materials exhibit excellent electrocatalytic activity for ORR with the onset and half-wave potentials of approximately 0.88‒0.90 and 0.80‒0.84 V, respectively, showing the 4e‒ electrons transfer path in 0.1 M KOH solution. The Mn-N-C materials also show enhanced activity for HER and OER in alkaline media.

Acknowledgment

The “Sustainably Produced Carbon Nanomaterials for Energy Applications (SuNaMa)” benefits from a 988000 € grant from Iceland, Liechtenstein, and Norway through the EEA Grants. The aim of the project is to develop innovative, high-performance, highly conductive, electrocatalytically active, durable, cost-effective, and high surface area nanocarbon materials. Project contract with the Research Council of Lithuania (LMTLT) No. is S-BMT-21-12 (LT08-2-LMT-K-01-055).
Transition Metal (Ni/Cu) Based Bimetallic Catalyst for Glycerol Oxidation
Authors: Gupta Saptarshi , De Mahuya 
Published: February 2024

Alcohol fuel cell is considered as one of the most promising green energy generation option. Glycerol can be used as a potent fuel because of its excellent energy density, ready availability, financial viability and minimal toxicity. Moreover, glycerol is also an active petroleum by-product. In direct glycerol fuel cell, precious noble metal based catalyst was extensively used as electro-catalyst for glycerol oxidation. The use of noble metal as catalysts restricted the viable commercialisation due to its high cost. This study intended to use transition metal such as nickel and copper based monometallic and bimetallic catalyst for glycerol oxidation to lower down the cost of commercialisation. These metals already proved to be efficient catalyst for electro-oxidation of methanol and ethanol [1-2]. Carbon was already proved to prominent support material for electro-catalyst due to high surface area and superior conductivity.
The metals were impregnated into carbon support followed by reduction under H2/Ar environment with 20 wt % metal loading. The weight ratio of Ni and Cu in bimetallic catalyst was fixed as 1:1. The average metal particle size of the catalysts varied between 7.8 to 16.3 nm. The cyclic voltammetry of different catalysts for 0.5 M glycerol oxidation in 1 M KOH is shown in Fig 1a). The onset potential of bimetallic catalyst (NiCu/C) was reduced to 0.20 V compared to their monometallic counterpart (0.39 V for Ni/C and 0.42 for Cu/C). The glycerol oxidation peak was observed at 0.71, 0.73 and 0.78 V for Cu/C, Ni/C and NiCu/C respectively. The specific activity and mass activity was shown in Fig 1b). The highest specific (76 mA/cm2) and mass activity (775 mA/mgmetal) was obtained for NiCu/C from glycerol oxidation. The obtained electrochemical surface area (ECSA) was highest for NiCu/C (99 m2/g) followed by Ni/C (44 m2/g) and Cu/C (34 m2/g). The higher activity of NiCu/C could be attributed to the lower Tafel slope, higher ECSA and charge transfer co-efficient. The EIS results conveyed that electro-oxidation process was slower than charge transfer process. Moreover, lowest time constants for the both the process was observed for NiCu/C catalyst. Hence, NiCu/C proved to be efficient electro-catalyst with superior activity for glycerol oxidation in direct glycerol fuel cell.

Fig 1. a) Cyclic voltammetry of different catalyst in 0.5 M glycerol and 0.1 M KOH and b) Specific and mass activity of different catalyst.

References

[1] X. Cui, W. Guo, M. Zhou, Y. Yang, Y. Li, P. Xiao, Y. Zhang, X. Zhang, ACS Appl. Mater. Interfaces, 7 (1), 493-503 (2015).
[2] A. N. Vyas, G. D. Saratale, S. D. Sartale, Int. J. Hydrog. Energy, 45 (10), 5928-5947 (2020).

Figure 1
Trimetallic Alloy as an Electrocatalyst for Direct Low Temperature Fuel Cells: The Case of MF Oxidation on Pt3Pd3Sn2
Authors: Yadav Radhey Shyam , Schechter Alex , Kornweitz Haya 
Published: February 2024

Methyl formate (MF) has been considered an attractive hydrogen carrier alternative fuel due to its high energy density, ease of storage and transport, and low boiling point (32o C @ 1 atmosphere) liquid. However, the low number of publications on efficient anodic catalysts is impeding the development of a direct methyl formate fuel cell (DMFFC).
In this study, a first-principles density functional theory (DFT) calculation was performed to study the MF electro-oxidation on the surface of the Pt3Pd3Sn2 (111) alloy. This surface was proven to be the most active in the anodic oxidation of other small organic molecules1,2. A detailed thermochemistry and kinetics study of MF oxidation was carried out to determine the active sites, most probable reaction pathway for the oxidation of CH3OCHO to CO2, and analyzed the dehydrogenation steps via direct (HCOOH pathway) and indirect (CO pathway) mechanisms.
The potential required for complete oxidation of MF to CO2 is 0.66 V. The study revealed that Sn plays an essential role in the mitigation of CO poisoning through water activation and surface oxide reaction mechanisms in a bifunctional manner. Furthermore, based on our findings, Pt and Pd work synergistically to enhance the utilization of active sites for the initiation of MF oxidation and promote HCOOH oxidation, which accelerates the kinetics of the electrochemical reaction.

References:

D. Kashyap et al., J Power Sources, 544, 231882 (2022).

M. G. Gebru, H. Teller, P. Subramanian, and A. Schechter, Energy Technology, 10, 2200835 (2022) https://onlinelibrary.wiley.com/doi/full/10.1002/ente.202200835.
Au-Based MOFs as Anodic Electrocatalysts for Direct Borohydride Fuel Cells
Authors: Belhaj Ines , Becker Alexander , Gusmão Filipe M.B , Šljukić Biljana , Chaves Miguel , Balula Salete S , Silva Luís Cunha , Santos Diogo M.F 
Published: February 2024

Researchers are exploring direct liquid fuel cells (DLFCs) as alternatives to proton-exchange membrane fuel cells because of their higher energy density and ease of storing and transporting the fuel. Direct borohydride fuel cells (DBFCs) are of particular interest as they offer a sustainable energy source with their high-power density output and the use of a highly alkaline NaBH4 medium [1]. Ensuring efficient and cost-effective catalysts for DBFCs is crucial for their commercial viability. Metal-organic frameworks (MOFs) have demonstrated significant potential as anodic electrocatalysts for BOR in DBFCs [2]. However, research should explore various modifications to MOFs, such as the incorporation of alternative metal ions or functional groups, to improve their catalytic efficiency and reduce cost. This study evaluated the performance of newly developed MOF-based electrocatalysts for DBFCs. Specifically, six MOF-based materials were synthesized and analyzed for their ability to facilitate borohydride oxidation (BOR) using cyclic voltammetry and chronoamperometry in alkaline media. MIL-101_Au@NH2 and MOF-808_Au@NH2 were found to be highly effective for BOR. The kinetic parameters for BOR with MOF-based electrocatalysts, including activation energy, reaction order, exchanged electrons, and anodic charge transfer coefficient, were determined. The activation energy for BOR was found to be 13.6 kJ mol−1 and 15.3 kJ mol−1 for MIL-101_Au@NH2 and MOF-808_Au@NH2, respectively. The number of transferred electrons, n, was found to be 7.0 and 3.1 for MIL-101_Au@NH2 and MOF-808_Au@NH2, respectively. This study demonstrates that MOF-based electrocatalysts can enhance DBFCs' performance, while offering insight into the potential usage of MOFs in other fuel cell technologies.
[1] B. Šljukić, D.M.F. Santos, "Direct borohydride fuel cells", in: "Direct Liquid Fuel Cells: Fundamentals, Advances, and Future", 1st ed., R.G. Akay, A.B. Yurtcan (eds.), Academic Press, USA, 203-232 (2021)
[2] G. Backovic, B. Šljukić, G.S. Kanberoglu, M. Yurderi, A. Bulut, M. Zahmakiran, D.M.F. Santos, Ruthenium (0) nanoparticles stabilized by the metal-organic framework as an efficient electrocatalyst for borohydride oxidation reaction, International Journal of Hydrogen Energy, 45, 27056-27066 (2020).