bluuebunny/crossref_metadata_2025_split huggingface dataset:
3M Ionomer Adsorption on Polymer Electrolyte Membrane Fuel Cell Electrodes
Authors: Cantillo Nelly M. , Peng Jing , Sneed Brian , Goenaga Gabriel A. , More Karren L. , Zawodzinski Thomas A. 
Published: February 2020

Previous ionomer adsorption (Figure 1) explorations in our group have shown significantly lower adsorption (lower Keq) of ionomer when platinum (Pt) nanoparticles are present on the carbon support.1 Such differences can suggest a higher affinity of the polymer chain to carbon, which could suggest that acidic groups on the carbon surface might participate in hydrogen bonding on dipole-dipole interactions with the hydrophilic unit in the polymer.1,2 This disagrees with many recent suggestions that the interactions with ionomer are driven by specifc adsorption of sulfonic acid or sulfonate on the Pt. Understanding such interactions can be key to further improve the Pt/Carbon/ionomer electrodes structure and, consequently, proton exchange membrane fuel cell (PEMFC) performance.
In this study, the adsorption of ionomer on a series of Pt:C (0:100, 30:70, 50:50 and 70:30) ratios using Vulcan XC-72 Carbon and Ketjenblack (KJB) supports were evaluated to further understand this interaction. The adsorption properties of water-dissolved 3M 825 equivalent-weight (EW) ionomer on both the carbon supports and the series of carbon-supported platinum (Pt/C) catalysts were studied with 400 MHz 19F Nuclear Magnetic Resonance Spectroscopy (NMR) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES).
A detailed structure characterization of the pristine supports and catalyst materials was achieved through Brunauer-Emmet-Teller (BET) nitrogen adsorption-desorption, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The adsorbed ionomer structure was also explored through NMR and Fourier-Transform Infrared (FTIR).
These results will be reported along with context from other studies of ionomer-supported catalyst interactions in the actual catalyst layer.

Acknowledgements

NMC gratefully acknowledges the support from a Fulbright Fellowship as well as the Office of Naval Research. Research was supported at ORNL by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy.

References

N. M. Cantillo, L. Li, J. Peng, G. A. Goenaga, and Thomas A. Zawodzinski ECS Trans., 80, 259–268 (2017) http://ecst.ecsdl.org/content/80/8/259.full.pdf.

S. Ma, Q. Chen, F. H. Jøgensen, P. C. Stein, and E. M. Skou, Solid State Ionics, 178, 1568–1575 (2007).

Figure 1
Unveilling the Degradation Pathway of Highly Defective Hollow PtNi/C in Operando Conditions
Authors: Dubau Laetitia , Asset Tristan , Nelayah Jaysen , Chattot Raphaël , Bordet Pierre , Drnec Jakub , Maillard Frederic 
Published: February 2020

Due to strain and ligand effects, the simultaneous presence of concave and convex surfaces and their highly-defective nanostructure (atomic vacancies, grain boundaries), highly defective hollow PtNi/C electrocatalysts have proven to enhance remarkably the oxygen reduction reaction (ORR) kinetics [1,2]. However, a technologically-relevant proton-exchange membrane fuel cell (PEMFC) cathode catalyst should be able to maintain its initial catalytic activity on the long-term. This is hardly feasible on nanocatalysts based on platinum alloyed with transition metals (PtM alloys, M being a transition metal) or M-rich core@Pt-rich shell nanoparticles due to the dissolution of the transition metal in the harsh operating conditions of a PEMFC cathode but the question remains open for nanocatalysts in which catalytic activity is not solely due to alloying effects. Herein, the stability of highly defective hollow PtNi/C nanoparticles was evaluated in X-Rays operando conditions under simulated PEMFC operating conditions (5,000 potential cycles between 0.6 and 1.0 V or 1.1 V vs. RHE at T = 80°C). The combined physical, chemical and electrochemical results show that the degradation pathway of highly defective hollow PtNi/C nanoparticles closely depends on the upper potential limit of the cycling protocol (Figure 1). Beyond 1V, the restructuring kinetics is accelerated compared to the 0.6 – 1.0 V protocol and the losses in ORR activity are related to both the weakening of strain and ligand effects associated with the dissolution of Ni atoms and to the decrease of the concentration of structural defects.
[1] L. Dubau, T. Asset, C. Bonnaud, R. Chattot, V. van Peene, F. Maillard, ACS Catal., 5 (2015) 5333-5341.
[2] L. Dubau, J. Nelayah, S. Moldovan, O. Ersen, P. Bordet, J. Drnec, T. Asset, R. Chattot, F. Maillard, ACS catal., 6 (2016) 4673-4684.

Figure 1
Employment of Fiber-Shaped Cobalt Modified with Gold Nanoparticles As Anode in Direct Borohydride and Hydrazine Fuel Cells
Authors: Balciunaite Aldona , Zabielaite Ausrine , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus 
Published: February 2020

In this study fiber-shaped cobalt was electroplated on the copper surface and modified with various amounts of gold nanoparticles (denoted as AuCofiber/Cu) with the aim to use it as the anode in direct borohydride and hydrazine fuel cells (DBFC and DHFC). Single fuel cell tests were performed by employing the prepared AuCofiber/Cu catalysts with the Au loadings in the range of 11-84 µgAu cm-2 as the anode and a Pt sheet as the cathode. The anolyte was composed of an alkaline mixture of 1 M NaBH4 + 4 M NaOH or 1 M N2H4 + 4 M NaOH and the acidic catholyte contained 5 M H2O2 + 1.5 M HCl. The performance parameters of the fuel cell was evaluated by recording the cell polarization and obtaining the corresponding power density curves at 25 ºC. А Nаfion®N117 membrаne wаs used to sepаrаte the аnodic аnd cаthodic compаrtments of the single fuel cells.
It was found that the direct N2H4-H2O2 and NaBH4-H2O2 fuel cells exhibited аn open circuit voltаge of cа. 1.7 and 1.9 V, respectively. Peаk power densities up to 162 and 188 mW cm-2 аt a temperature of 25oC were obtained from N2H4-H2O2 and NaBH4-H2O2 fuel cells, respectively. It is worth to note that the highest specific peаk power density values of ca. 12 kW g–1
Аu and 15 kW g–1
Аu were obtаined, when employing the АuCofiber/Cu catalyst with the Аu loаding of 11 µgАu cm–2 аs the аnode cаtаlyst.

Acknowledgment

This research was funded by a M-ERA.NET grant (No. M-ERA.NET-1/2016) from the Research Council of Lithuania.
Low Cost PCB Fuel Cells Based for Small Electronic Applications
Authors: Parra Puerto Andres , Hakola Liisa , Kucernak Anthony R. J. 
Published: February 2020

An important aspect to enhance the introduction of the fuel cells systems in the market, is decreasing the cost of manufacturing, obtaining a flexible way to extend their use in different applications. The possibility to use the well-defined PCB manufacturing technic to develop fuel cells stacks can help to obtain a low-cost and tuneable method for their production [1]. Using this manufacturing method is easy to control the size and adjust the power requirements for different electronic devices as electrochromic devices, smartphone chargers, electric vehicles, etc. As well, due to their flat configuration is very easy to stack many of them in small spaces. In this work we design and develop a mini and micro stack DMFC open cathode PCB cell using low cost materials on the bipolar plates and electrodes. In general, for the bipolar plates different metal and ink coatings were used to improve the durability and the electrical contact. But them requires few steps to obtain the final stage, in our case we moved to a graphitic flexible material with very high corrosion resistance and conductivity giving the possibility to avoid the coating steps. In the case of the electrodes, a non-precious metal and very high poison resistance catalyst developed in our lab was used as cathode [2]. In the anode part, an inkjet printed electrodes where used. This method gives the possibility to decrease the loading of catalyst obtaining a really good performance in the Fuel Cell. For the micro-DMFC we developed two setups, one similar to the mini stack cell and the other one, in a complete passive configuration. The design of the fully passive cells gives the possibility to inject the methanol solution in the anode reservoirs. This micro stack cell was developed to power up an autonomous electrical biosensor synergistically assembled inside a passive DMFC for screening cancer biomarkers included in the European 2020 project called Symbiotic.
[1] O. A. Obeisun et al., “Development of open-cathode polymer electrolyte fuel cells using printed circuit board flow-field plates: Flow geometry characterisation,” Int. J. Hydrogen Energy, vol. 39, no. 32, pp. 18326–18336, 2014.
[2] D. Malko, T. Lopes, E. Symianakis, and A. R. Kucernak, “The intriguing poison tolerance of non-precious metal oxygen reduction reaction (ORR) catalysts,” J. Mater. Chem. A, vol. 4, no. 1, pp. 142–152, 2016.

Figure 1
The Enhancement of Hydrogen Oxidation Activity and the Optimization of Alloy Composition in PdRu Nanoparticle Catalysts
Authors: Kwon Kyungjung , Jin Seon-ah , Cho Jinwon , Ham Hyung Chul , Pak Chanho 
Published: February 2020

Fuel cells are believed as promising power sources with many advantages including their high efficiency and environment-friendliness. Proton exchange membrane fuel cells (PEMFCs), of which usage can be expected as power sources as automobiles and so on, have yet several problems to resolve for the commercialization. Among them, the high price due to the scarcity of Pt, which is used as anode and cathode catalysts, is one of the most serious issues. Pd is a natural choice to replace Pt because the hydrogen oxidation reaction (HOR) activity of Pd is the next to that of Pt, and Pd is at least fifty times more abundant on earth than Pt. Pd is a more attractive substitute for Pt because of its higher intrinsic CO tolerance than Pt, especially as HOR catalysts for PEMFC where the tolerance of CO, a major impurity of hydrogen fuel, is crucial. Although Pd has comparable HOR activity to Pt, the exclusive use of Pd as anode catalysts of PEMFC has not been satisfactory for the replacement of Pt. We confirmed in our previous report (K. Kwon et al., Catal Today, 232 (2014) 175) that the insufficient HOR activity of Pd could be supplemented by coupling with other elements or compounds such as Ru and tungsten oxide. To investigate the effect of alloying with Ru thoroughly, the calculation of hydrogen binding energy was performed on the basis of spin polarized density functional theory. Pure Pd(001) and Ru(001), Pd monolayer on Ru, and Pd bilayer on Ru are considered as model systems in the calculation. Strain and ligand effects are only applicable to bimetallic models (Pd monolayer on Ru and Pd bilayer on Ru). The negative sign of strain and ligand effects stands for a decrease in binding energy for PdRu alloy.
Meanwhile, instead of making an effort to turn the model alloy systems into nanoparticles of Pd mono/bilayer on Ru, which would not be realistic in a few nm dimension, the actual confirmation of HOR enhancement at the level of half cell and PEMFC single cell was obtained by fabricating homogeneous PdRu alloy nanoparticles on carbon support. PdRu nanoparticles of different Pd:Ru atomic ratios of 1:0, 9:1, 1:9, and 0:1 were characterized with TEM and XRD, and compared with a commercial state-of-the-art Pt-based anode catalyst (PtRu1.5/C) in electrochemical experiments. The PdRu9 catalyst shows the highest HOR activity among the PdRu samples, which is comparable to the PtRu catalyst, even though the respective Pd and Ru have lower activity than PtRu. The highest HOR activity of the Ru-richest PdRu nanoparticles could be in line with the highest HOR activity of the Ru-richest PdRu model system (Pd monolayer on Ru).
Zirconia Doped Ceria Cathodic Interlayer By Atomic Layer Deposition for Low Temperature Solid Oxide Fuel Cell
Authors: Yang Byung Chan , Go Dohyun , Oh Seongkook , Shin Jeong Woo , An Jihwan 
Published: February 2020

Solid oxide fuel cell (SOFC) has the advantages of high energy conversion efficiency, fuel flexibility, and environment friendliness. However, conventional SOFC also has limitations in applying to various fields due to the high operating temperature of 800-1000℃. Therefore, low temperature SOFC (LT-SOFC) (≤ 500 ℃), which can be operated at relatively low temperature, are being widely researched these days. Operation losses of LT-SOFCs, however, have to be minimized to maintain the performance even at low temperature; especially, at low temperature, the activation loss at cathode is the dominant loss due to sluggish oxygen reduction reaction (ORR). The adoption of cathode interlayer such as doped ceria has been researched as an effective method to dramatically lower the cathodic activation loss in LT-SOFCs.
In this study, we used zirconia-ceria composite cathodic interlayer fabricated by atomic layer deposition (ALD) to improve the performance of SOFC at low temperature. Ceria-based materials with high oxygen ion conductivity and high oxygen surface exchange coefficient at relatively low temperatures have been widely used as cathodic interlayers for LT-SOFCs, but the relatively low chemical stability has been the practical issue. Zirconia doped ceria (ZDC), on the contrary, is known to have better catalytic properties than pure ceria with even improved chemical stability. We show that the performance of LT-SOFC can be significantly enhanced by using ZDC as cathodic interlayer. The ZDC interlayer was deposited on the cathode side surface of yttria stabilized zirconia (YSZ) electrolyte using ALD. ALD is beneficial in depositing ultra-thin film with the capability to precisely control the composition and the thickness of films. Each interlayer of 20 nm-in-thickness was deposited with different ratios of zirconia and ceria; the molar ratio of zirconia was varied at 0, 30, 50, 80, and 100 mol%, respectively. The composition of the interlayer was analyzed by X-ray Photoelectron Spectroscopy (XPS) and the electrochemical performance was measured at 450℃ by using current-voltage characterization and electrochemical impedance spectroscopy (EIS). The maximum power density of the cell with the ZDC interlayer improved by 50% compared to that of the reference cell without the interlayer, which is even higher those of the cells with zirconia-only or ceria-only interlayers. In addition, the activation resistance of the cell with ZDC was decreased by ~50% in comparison with the cell without interlayers as shown in EIS measurements.
On the Effect of Clamping Pressure and Method on the Current Mapping of Proton Exchange Membrane Water Electrolysis
Authors: Al Shakhshir Saher , Zhou Fan , Kær Søren Knudsen 
Published: February 2020

The degradation of the electrochemical reaction of the proton exchange membrane water electrolysis (PEMWE) can be characterized using in-situ current mapping measurements (CMM). CMM is significantly affected by the amount of clamping pressure and method. In this work the current is mapped downstream at the cathode side of 50 cm2 active area single PEMWE cell at different clamping pressure and different clamping methods. Two clamping methods are used; bolting the cell with 8 bolts around the active area and clamping the cell from the whole area of the end plate using highly pressurized clamping set-up. CMM is carried out using S++ setup, where the segmented plate is placed between the current distributor and flow field plate downstream at the cathode side of the PEMWE cell. The segmented plate consists of 100 segments over the 50 cm2, thus each segment area is 0.5 cm2.
Initial results show that, the clamping pressure effect on the CMM is not symmetrical in both clamping method and it directly affects the CMM homogeneity. Also it is concluded that higher PEMWE cell performance not necessary means more homogeneous CMM over the cell area.

Figure 1
Stable Silicon-Based Sandwich Photoelectrode for Efficient Solar Hydrogen Evolution
Authors: Cheng Chaoqun , Du Kang , Zhang Zengxing , Li Gang , Wang Kaiying 
Published: February 2020

Photoelectrochemical water splitting, consisting of photoanode and photocathode used for water reduction and oxidation, is a potential route to store the solar energy into chemical fuels. In terms of the required earth abundance, cheapness and proper band gap edges (1.12 eV), silicon is an attractive photoelectrode material. Unfortunately, silicon suffered from the instability and low efficiency due to the severe photocorrosion and passivation in the reaction electrolyte, even though limited performance has been achieved for water splitting development. [1-3].
In this work, in order to enhance the stability and photoelectrochemical efficiency, we fabricated silicon-based sandwich photoelectrodes with mediated protection layer of sputtered Molybdenum thin film, which is covered with hand-sprayed MoS2 as the catalyst, as shown in the fig. 1(a). The samples are marked with a, b, c and d separately after different thermal annealing time of 0h, 1h, 2h, 3h in the static Nitrogen atmosphere. After proper annealing, the formed nanoporous surficial structure could be observed in the SEM images (fig. 1(b)) with pore diameters ranging from 10 to 50 nm. These porous networks offer much more active sites for water splitting. The effect of annealing temperature on optical response is shown in fig. 2(a). The UV-Vis spectra show that the annealed surficial MoS2 exhibits extended optical responses to the longer wavelength region, indicating the potential enhanced visible light absorption. What’s more, in the photoluminescence (PL) spectra (Fig. 2(b)), the weaker PL intensity are observed after covering MoS2 on the top surface of Mo and essential annealing process, suggesting the suppressed recommendation of the photoexcited electrons and holes in the interface and therefore improved solar energy conversion.
In conclusion, the silicon-based sandwich photoelectrode with enhanced visible light absorption and conversion is fabricated through facile processes. This novel low-cost silicon-based photoelectrode possess potential enhanced efficiency and stability applied in the photoelectrochemical water splitting system.

Acknowledgments: The authors gratefully acknowledge the financial support from Norwegian Research Council FRINATEK programme (231416/F20), and China Scholarship Council (CSC, Grant No.201506930002). The Research Council of Norway is acknowledged for the support to the NorFab, project number 245963/F50.

References

[1] M. J. Kenney, M. Gong, Y. Li, J. Z. Wu, J. Feng, M. Lanza, H. Dai, Science, 343 (6160), 836-840 (2013).
[2] S. Hu, M. R. Shaner, J. A. Beardslee, M. Lichterman, B. S. Brunschwig, N. S. Lewis, Science, 344 (6187), 1005-1009 (2014).
[3] J. Feng, M. Gong, M. J. Kenney, J., Z. Wu, B. Zhang, Y. Li, H. Dai, Nano Res., 8 (5), 1577–1583 (2015).

Figure 1
(Invited) Electrochemical Ammonia Synthesis Using Intermediate Temperature Proton Conducting Membranes
Authors: Kreller Cortney R. , Ramaiyan Kannan Pasupathikovil , Maurya Sandip , Parker Nia , Mukundan Rangachary , Kim Yu Seung , Garzon Fernando H 
Published: February 2020

Due to the intermittency of many renewable energy sources, their potential to significantly participate in the overall energy mix is strongly dependent on our ability to identify and develop efficient and cheap energy storage technologies1. Liquid fuels are an appealing option with energy densities typically 10-100x higher than batteries. Ammonia, in particular, has many attributes that make it the ideal energy storage compound including high energy density and an existing infrastructure for transportation. The highly developed, large-scale production of ammonia via Haber-Bosch process is not suitable for energy storage applications due to the high-temperatures and pressures used. Theory2 and experiment3 suggest that a more suitable approach is the production of ammonia from nitrogen and water via electrosynthesis whereby small-scale reactors could enable distributed ammonia production closer to the consumer and be more compatible with energy inputs from intermittent renewable energy resources - improvements that could dramatically reduce the energy and carbon intensity of ammonia production and distribution.
Prior research pursuing the electrosynthesis of ammonia has focused primarily on the use of proton conducting electrolytes at high temperatures, >600˚C or low temperatures, <100˚C due to materials limitations in the intermediate temperature range. The intermediate temperature range is particularly advantageous as lower temperatures favor the thermodynamics of the forward reaction to form NH3, while higher temperatures aid in the breaking of the incredibly stable di-nitrogen bond (946 kJ/mol). In order to access this intermediate temperature range of operation, we have developed a composite SnP2O7/Nafion based electrolyte material that exhibits conductivity on the order of 20 mScm-1 at 200˚C. We have demonstrated a maximum ammonia production rate of ~1x10-8molcm-2s-1 at 200˚C using N2 and H2 as reactant gases and Pt-based electrodes. This talk will discuss the factors influencing production rates and current efficiencies of these intermediate temperature devices.

References

J. B. Goodenough, H. D. Abruna and M. V. Buchanan, 2007.

T. H. Rod, A. Logadottir and J. K. Nørskov, The Journal of Chemical Physics 112 (12), 5343 (2000).

G. Marnellos and M. Stoukides, Science 282 (1998).

Acknowledgements

This project is supported by ARPA-E under Award No. DE-AR0000687.
Doping Engineering in Type-II Homojucntion to Enhance the Photoelectrochemical Performance of Thin-Film BiVO4 Photoanode
Authors: Baek Ji Hyun , Lee Jae Myeong , Jung Hyun Suk 
Published: February 2020

Photoelectrochemical (PEC) water splitting with metal oxides photoelectrodes is a promising renewable technology because of their good performance for light harvesting and stability as well as good properties such as naturally earth-abundant, harmless and economical. BiVO4 has been regarded as a major metal oxide material in the PEC photoanode due to the suitable band gap for efficient light absorption and advantage of solar-to-hydrogen conversion efficiency. However, the PEC performance of this single absorber material is limited due to its charge recombination in bulk, interface and surface derived by poor carrier diffusion property, electrical conductivity and water oxidation kinetics. Until now, many attempts of junction of two materials such as BiVO4/WO3, BiVO4/ZnO or BiVO4/Bi2WO6 to form a type-II heterojunction has been introduced to be a feasible mean to improve the charge separation and transport efficiencies.
In this study, we have modified the BiVO4 single absorber with Zn and Mo doping and introduced the type-II homojunction BiVO4 photoanode for efficient PEC water splitting via a facile solution method. Interestingly, the Zn and Mo doping treatment let BiVO4 thin-film change the Fermi level and form the staggered band alignment. It is helpful to enhance the charge separation in bulk and charge transfer in surface of BiVO4 due to the interference of surface trapping of photogenerated charge carriers with type-II homojunction followed by the enhancement of PEC water splitting performances.