bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Carbon-Based Non-Precious Metal Catalyst Mnhmta/C for Oxygen Reduction Reaction
Authors: Si Yujun , Xiong Zhongping , Li Minjiao 
Published: February 2020

A non-precious metal catalyst for oxygen reduction reaction was prepared by heat-treating a precursor from the mechanical mixture of acetylene black, hexamethylenetetramine and MnCl2.4H2O. The precursor contains 1.0g of acetylene black, 1.0g of hexamethylenetetramine and 0.50g of MnCl2.4H2O. The precursor was heat-treated at 700℃ for 2 hours. In the heat-treating, a nitrogen gas was used as protective gas to get an inertia atmosphere. And the protective gas was controlled as following two modes: one is that the protective gas was shut after 30 minutes and before heat-treating, the other is that the protective gas was not shut in the thorough heat-treating process. The resulted products were labelled as MnHMTA/C(A) and MnHMTA/C(B), respectively. Figure 1 shows the catalytic activity towards oxygen reduction reaction of the two catalysts. It can be seen that the MnHMTA/C catalyst exhibits good activity to oxygen reduction reaction with an onset reduction potential of 0.55V (vs. SCE). In addition, the activity of MnHMTA/C(B) is better than MnHMTA/C(A). The reason is that the decomposed product of hexamethylenetetramine will exhaust with nitrogen gas in the preparation of MnHMTA/C(A), which affects the formation of active sites and worsens the catalytic activity of the MnHMTA/C(A) catalyst.

Acknowledgments

This work was supported by the Specialized Research Fund for the Doctoral Program of Sichuan University of Science and Engineering (No. 2012RC16) and the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education (No. LYJ1206, LYJ1401).
Figure 1 Linear sweep voltammograms of (a) acetylene black, (c) MnHMTA/C(A) and (d) MnHMTA/C(B) catalysts in 0.5M H2SO4 solution saturated by O2, and (b) MnHMTA/C(A) catalyst in 0.5M H2SO4 solution saturated by N2
。
Degradation of Polymer Electrolyte Membrane Fuel Cell Under Pressure Cycle
Authors: Jung Ju Hae , Yoo Sung Jong , Kim Hyoung-Juhn , Jang Jong Hyun , Nam Suk Woo , Cho Eun Ae 
Published: February 2020

Polymer electrolyte membrane fuel cell (PEMFC) is known as environmentally friendly energy sources for portable, backup power, and transportation applications. The performance and durability of PEMFC are affected by operating conditions such as the temperature, pressure, and humidification. Many studies have investigated of operating back pressure. An increase of back pressure can significant improved thermodynamics, kinetics and mass transfer in PEMFC. Wang et al. [1] studied the effect of different fuel cell operating temperatures, cathode and anode humidification temperatures, pressures and various combinations of these parameters experimentally. They found that cell performance is increased under high pressure operation due to the increase of reactant partial pressure and the exchange current density. Zhang et al. [2] carried out experiments on PEMFC at pressures of 1–3 atm. They confirmed that a low gas flow rate and a high back pressure improved the PEMFC performance using the Nafion 112 membrane at 0% RH. However, membrane electrode assemblies (MEAs) are degraded by operation of high back pressure in PEMFC. Because of the polymer chains of membrane breaks by radical attack as chemical degradation due to gas permeability. Also, mechanical degradation on MEAs occurs in many forms including cracks, pinhole and blisters by the operation of high back pressure.[3]
In this study, we examined effects of pressure cycle operation during the constant current (CC) mode on degradation of PEMFC. After pressure cycle, open circuit voltage (OCV) and current density at 0.6V were seriously decreased with increases in resistance and decreases in electrochemical active surface area (ECSA). In addition, we confirmed the pinhole in membrane, decrease in the catalyst layer thickness and interfacial separation in gas diffusion layer (GDL). Therefore, the pressure cycle generated the severe degradation in MEAs and they can the cause of early life failures.
References
[1] Wang L, Husar A, Zhou T, Liu H., Int J Hydrogen Energy, 28 1263, (2003).
[2] Zhang J, Tang Y, Song C, Cheng X, Zhang J, Wang H., Electrochim Acta
52, 5295 (2007).
[3] S. Vengatesan, M.W. Fowler, X.-Z. Yuan, H. Wang, J. Power Sources
196, 5045 (2011).
Electrochemical Performance of MEAs with Pt/SnO2 Mixed with Conductive Fillers
Authors: Nagamatsu Yohei , Kanda Kohei , Noda Zhiyun , Hayashi Akari , Sasaki Kazunari 
Published: February 2020

1.
Introduction

Polymer electrolyte fuel cells (PEFCs) have been attracted for both automobile and residential use. However, PEFCs still have some problems to be solved, such as durability. In particular, during the actual operating condition of fuel cell vehicles (FCVs), carbon supports, which have advantages of high conductivity, high specific surface area, and high porosity, are easily degraded through oxidation at the cathode side. Therefore, in our laboratory, SnO2 supports were rather focused on as popular alternative oxide-based support materials because of their thermodynamic stability. Durability as electrocatalysts has been confirmed in the half-cell [1, 2]. Nevertheless, the agglomeration of SnO2 particles leads to low performance when MEAs are made with SnO2 based electrocatalysts. Thus, the objective of this research is to develop MEAs with high performance and durability using SnO2supports.

2. Experimental

Nb-doped SnO2 was prepared to increase the electric conductivity in this study. Sn0.98Nb0.02O2 was synthesized via an ammonia co-precipitation method, using SnCl2・2H2O and NbCl5. Pt nanoparticles were decorated on such a metal oxide support utilizing a platinum acetylacetonate complex. I-V characteristics of MEAs were evaluated as well as their ohmic resistance measured by an impedance method. Further, based on the protocol recommended by the Fuel Cell Commercialization Conference of Japan (FCCJ) [3], Durability of MEAs was investigated at the potential cycle of 1.0 ~ 1.5V, and also their microstructures were evaluated by a field emission scanning electron microscope (FESEM).

3. Results and Discussion

By comparing the durability of MEAs made with three different cathode electrocatalysts, such as Pt/Carbon, Pt/Sn0.98Nb0.02O2, and Pt/Sn0.98Nb0.02O2+5wt.%VGCF-H (a conductive filler), MEA made with Pt/ Sn0.98Nb0.02O2+5wt.%VGCF-H showed the highest performance and durability [4]. Furthermore, optimization of the ratio of Nafion and VGCF-H was performed. As shown in Fig. 1, MEA with Pt/ Sn0.98Nb0.02O2+25wt.%VGCF-H+13wt.%Nafion showed highest I-V performance in this study. The microstructure with good distribution of conductive fillers is also shown in Fig. 2. This suggests that it is possible to reduce the ratio of Nafion and further optimize the amount of VGCF-H. Durability and microstructures of MEAs will be discussed in detail.
References
1) F. Takasaki, S. Matsuie, Y. Takabatake, Z. Noda, A. Hayashi, Y. Shiratori, K. Ito, and K. Sasaki, J. Electrochem. Soc., 158(10) B1270-B1275 (2011).
2) A. Masao, S. Noda, F. Takasaki, K. Ito, and K. Sasaki, Electrochem. Solid-State Lett., 12(9), B119 (2009).
3) A. Ohma et al., ECS Trans, 41755 (2011).
4) K. Kanda, Z. Noda, Y. Nagamatsu, T. Higashi, S. Taniguchi, S.M. Lyth, A. Hayashi, and K.Sasaki, ECS Electrochem. Lett., 3(4) F15-F18 (2014).
Optimization of Operation Conditions for Alkaline Membrane Fuel Cells
Authors: Watanabe Shin , Isomura Takenori , Yamaguchi Masao , Negishi Takayuki , Sadasue Kazuyuki , Hironaka Yoshimi , Oda Kengo , Matsumura Yasunori , Kikkawa Yuki , Okamura Takaaki , Furuya Hirotoshi , Yanagi Hiroyuki 
Published: February 2020

We have been developing materials for Alkaline membrane fuel cells(AMFCs) for about 10 years. Alkaline membrane fuel cell (AMFC) is one of the polymer electrolyte fuel cells (PEFCs) which uses anion exchange membrane and anion conductive ionomer as polymer electrolyte materials. AMFCs have some advantages over proton-exchange membrane fuel cells(PEMFC) 1-2).
(1) The high pH environment of AMFCs allows the use of non platinum catalysts.
(2) The kinetics of the ORR reaction is more facile in alkaline environment than in acid environment.
AMFCs have been attracting worldwide attentions, and the number of report is increasing year by year.
We have already demonstrated the relatively high AMFC performances with hydrogen fuel, and have confirmed several features specialized to AMFCs, namely CO2 self-purging phenomena3), which could be a solution against serious CO2
problem in AMFCs4-6), and the effective water transport from anode to cathode side, which prevent the lack of water needed for cathode reaction7).
In this presentation, we are going to show some new aspects for AMFC operation conditions such as temperature, water management and choice of materials.

References

H. A. Gasteiger , FC-EXPO 2008, Technical conference fc-10.

J. R. Varcoe, R. C. T. Slade, E. Lam How Yee, S. D. Poynton, D. J. Driscoll, D. C. Apperley, Chem. Mater., 19, 2686 (2007)

L. A. Adams, S. D. Poynton, C. Tamain, R. C. T. Slade, J. R. Varcoe, ChemSusChem, 1, 79 (2008).

H. Yanagi, K. Fukuta, ECS transactions, 16, 257 (2008).

K. Fukuta, H. Inoue, S. Watanabe, H. Yanagi, ECS transactions, 1
9, 23 (2009).

H. Yanagi, S. Watanabe, K. Sadasue, T. Isomura, H. Inoue, K. Fukuta, Abstract of 216th ECS Meeting, #341 (2009).

T.Isomura, K.Fukuta, H.Yanagi, S.Ge and C.Y. Wang, Abstract of 219th ECS Meeting, #221 (2011).
Microwave-Assisted Synthesis of Graphene Supported Silver and Platinum-Silver Nanoparticles for Application in Fuel Cells
Authors: Jagminiene Aldona , Matuseviciute Agne , Balciunaite Aldona , Vaiciuniene Jurate , Kondrotas Rokas , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus 
Published: February 2020

This work is focused on the preparation of the graphene supported silver and platinum-silver catalysts (denoted as Ag/GR and PtAg/GR) as electrocatalysts for the oxidation of borohydride, hydrazine and formaldehyde in an alkaline medium. The Ag/GR and PtAg/GR catalysts were prepared via rapid microwave heating method.
Transmission Electron Microscopy and Inductively Coupled Plasma Optical Emission Spectroscopy were employed to characterize the morphology, structure and composition of the synthesized catalysts. The kinetics of borohydride, hydrazine and formaldehyde oxidations was investigated on the the graphene supported silver and platinum-silver catalysts by a variety of electrochemical techniques (cyclic voltammetry, chronoamperometry and chronopotentiometry).
The data of electrochemical oxidation of borohydride, hydrazine and formaldehyde on the graphene supported silver and platinum-silver catalysts synthesized by means of microwave heating irradiation under various conditions are presented.

Acknowledgement

This research was funded by a Grant (No. ATE-08/2012) from the Research Council of Lithuania.
Investigation of Passive DEFC Mini-Stacks at Ambient Temperature
Authors: Vélez-Denhez Alejandra , Córdoba-Moreno Marlina Olyissa , Lizcano-Valbuena William H. 
Published: February 2020

In this work we show the results of ministacks of direct ethanol fuel cells (DEFC) at 25 oC. Result obtained with a passive DEFC using 2 mgPtRu/C in anodes and 3 mg of Pt in cathodes, when the alcohol concentration was 1 M, showed a power density equal to 0.875 mWcm-2 for electrodes with area equal to 25 mm2 . Results related with Nafion content in the catalytic layers are discussed. Stacks using three similar cells showed 2.4 mWcm-2 indicating the good performance of the system.
The performance of mini stacks operated with electrodes of 5 mm2 showed the dependence of the mass transport of ethanol and of the configuration of the stacks (zig zag and flip flop). The better results were obtained with a zig zag interconexion.
A comparison from fuel cell performance was done using ethanol and methanol. The best result of the stack using methanol (5M) was 60% higher than when ethanol (2M) was used.
Evaluation of Durability with MEAs Made by Graphitized Carbon Supports
Authors: Hayashi Akari , Zhao Xiaojing , Minamida Yasuto , Kitamura Masahiko , Noda Zhiyun , Sasaki Kazunari 
Published: February 2020

Polymer electrolyte fuel cells (PEFCs) are attractive energy device for our future society. Even so, improvement of durability is still desired. Especially for fuel cell vehicles (FCVs), carbon oxidation derived by the start/stop cycle becomes a problem. We have been working on surface graphitized carbon supports to increase the durability toward carbon oxidation. Up to date, durability of electrocatalyts has been improved as much as twice in the half-cell reaction just through the heat treatment of carbon supports [1]. In this study, MEAs are prepared with such electrocatalysts. Their initial performance and durability was evaluated in detail by both electrochemical and electron microscopic methods.
In this study, MEAs, whose diameter was about 8 mm, were used. For the anode, commercially available Pt/Ketjen black (TEC10E50E, TKK corp.) was in use. For the cathode, Pt deposited on Vulcan carbon or on graphitized Vulcan carbon materials, named as Pt/VC or Pt/GVC, were prepared in our lab. Here, Pt/GVC was made through the heat treatment at 1600 oC. For the electrochemical analyses, I-V characteristics were evaluated. Regarding to durability, the potential cycle tests assuming the start/stop cycle of FCVs, which suggested by Fuel Cell Commercialization of Japan (FCCJ) [2], were used. Furthermore, nanostructures of cathode layers were observed using Hitachi HF-3300.
Initial IV characteristics of MEAs with Pt/VC and Pt/GVC were almost the same. However, their durability resulted in different. MEA with Pt/GVC showed much improved durability. To understand the change in microstructures of the cathode layer, a part of cathode layer was picked up by a FIB microprobe, placed on the microgrid, and observed by SEM/STEM at the same time. As shown in Fig. 1, in case of Pt/VC cathode layer, more Pt particles were observed after the 5000 potential cycle test. Surprisingly, a lot of Pt particles existed inside carbon supports, which was clearly understood form the amount of Pt on carbon surface in the SEM image. Such embedded Pt particles were much suppressed in case of Pt/GVC cathode layer. Our new methods to study degradation process using in-situ SEM/STEM observation will be also discussed.
Reference
[1] Z. Zhao et al., Electrochim. Acta, 97, (2013) 33.
[2] A. Ohma et al., ECS Trans, 41 (2011) 755.
Effect of through-Plane Polytetrafluoroethylene Distribution in a Gas Diffusion Layer
Authors: Ito Hiroshi , Nakano Akihiro , Iwamura Takuya , Someya Satoshi , Munakata Tetsuo 
Published: February 2020

During operation of a proton exchange membrane fuel cell (PEMFC), the oxygen reduction reaction rate at the cathode is the limiting kinetic step and determines the maximum operating current density. This rate strongly depends on the transport rate of oxygen from the flow channel to the catalyst sites. Although the electrolyte membrane needs liquid water to retain proton conductivity, the oxygen gas transport can be greatly hindered when liquid water accumulates either in the catalyst layer (CL) or the gas diffusion layer (GDL) of the cathode. Consequently, for optimal water management and performance in PEMFCs, water retention/expulsion properties must be carefully balanced.
We previously investigated the relationship between the treatment process of polytetrafluoroethylene (PTFE) and the resulting PTFE distribution in through-plane direction of carbon papers [1]. The dependence of PTFE distribution on the PTFE drying conditions was examined using SEM-EDS analysis. The EDS image maps revealed that the PTFE distribution strongly depended on the drying condition; PTFE-drying under atmospheric pressure created highly heterogeneous PTFE distributions in the through-plane direction, with high concentrations near both the upper and lower surfaces, whereas PTFE-drying under vacuum pressure created a relatively uniform PTFE distribution.
In this study, in order to investigate the effect of PTFE though-plane distribution on the water discharge characteristic, limiting current measurements were performed under various humidity conditions using a small-scale PEMFC, which has the electrode area of 1 cm2. Based on the limiting current measurement, we could evaluate the gas transport resistance through the carbon paper GDL [2,3]. Because the small-scale cell was applied, we could minimize the effect of the distribution of current density and humidification, that is, the effect of local flooding across the flow channel depending on the change of humidification.
References

H. Ito et al., J. Power Sources , 248, 822 (2014).

D. R. Baker et al., J. Electrochem. Soc., 156, B991 (2009).

N. Nonoyama et al., J. Electrochem. Soc., 158, B416 (2011).
Niobium Carbide Based Catalyst Supports for PEMFC Cathodes
Authors: Nabil-Moreau Yannick , Cavaliere Sara , Jones Deborah , Roziere Jacques , Hards Graham , Sharman Jonathan , Harkness Ian 
Published: February 2020

Recent research has shown that alternative compositions such as metal carbides and nitrides can potentially present the required properties of conductivity and (electro)chemical stability to replace the carbon blacks conventionally used as electrocatalyst supports in Proton Exchange Membrane Fuel Cells (PEMFC). We are currently investigating a range of synthesis routes leading to electronically conductive and chemically stable support materials based on NbC with controlled morphologies and porosity. For instance, a template-assisted method associated with specific thermal treatments1 has led to a nanostructured carbide with a high specific surface area (70 m2
g-1) and an electronic conductivity comparable to that of carbon (103 S.m-1), while a synthesis route involving electrospinning and reduction in methane provides niobium carbide nanofibres. Furthermore, hollow structures with controlled porosity can be obtained by varying the synthesis parameters. These various supports have been catalysed by deposition of platinum nanoparticles, synthesised by a microwave assisted polyol method. This contribution will describe the chemical and electrochemical characterisation of Pt on NbC-based supports, and compare the properties to those of other candidate support materials such as titania and tin oxide.
1. J. Bernard D'Arbigny, G. Taillades, M. Marrony, D. J. Jones, J. Roziere, Chemical Communications, 47, 7950-7952 (2011).
Microstructure at the Ionic Liquid/Electrode Interface
Authors: Haverhals Luke M. , Zibart Christina , Egan Bryce , Parr Daniel 
Published: February 2020

In the past decade, ionic liquids (ILs) have been investigated as electrolytes for energy conversion applications such as capacitors
[i]

,[ii]
, batteries
[iii]

,[iv]
, fuel cells
[v]

,[vi]
, and solar cells.
[vii]

,[viii]
While significant progress has been made towards utilizing these remarkably adaptable materials for specific applications, much work remains to generate technologically and economically relevant devices and processes. Fundamental characterizations of IL-based electrolyte/electrode systems are crucial to continued development for these enterprises.
[ix]
In specific, detailed descriptions and understanding of electrolyte/electrode interfaces are prerequisites to engineered progress because adsorbed species and their associated interfacial dynamics play critical roles in determining device efficiencies.
[x]

,[xi]
Our initial studies focus on spectroscopic techniques such as surface enhanced infrared absorption (SEIRA) spectroscopy to characterize interfacial structure and dynamics between ionic liquid media and electrode surfaces during electrochemical perturbation. More specifically, we will discuss characterizations of ILs composed of imidazolium-based cations with alkylsulfate, tetrafluoroborate, thiocyanate, dicyanamide, and bis(trifluoromethylsulfonyl)imide anions at noble metal electrodes (i.e, Au).

[i]. T. Sato, G. Masuda, K. Takagi, Electrochim. Acta, 2004, 49, 3603-3611.
[ii]. A. Orita, K. Kamijima, M. Yoshida, J. Power Sources, 2010, 195, 7471-7479.
[iii]. A. S. Best, A. I. Bhatt, A. F. Hollenkamp, J. Electrochem. Soc., 2010, 157, A903-A911.
[iv]. J.-K. Kima, A. Matica, J.-H. Ahnb, P. Jacobsson, J. Power Sources, 2010, 195, 7639-7643.
[v]. S.-Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc., 2010, 132, 9764-9773.
[vi]. M. Guo, J. Fang, H. Xu, W. Li, X. Lu, C. Lan, K. Li, J. Membr. Sci., 2010, 362, 97-104.
[vii]. P. K. Singh, N. A. Jadhav, S. K. Mishra, U. P. Singh, B. Bhattacharya, Ionics, 2010, 16, 645-648.
[viii]. C.-P. Lee, P.-Y. Chen, R. Vittal, K.-C. Ho, J. Mater. Chem., 2010, 20, 2356-2361.
[ix]. C. Aliaga, C. S. Santos, S. Baldelli, Phys. Chem. Chem. Phys., 2007, 9, 3683-3700.
[x]. A. J. Bard, L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, 2nd ed., 2002, John Wiley & Sons, Inc., New York, NY.
[xi]. M. Yoshida, A. Yamakata, K. Takanabe, J. Kubota, M. Osawa, K. Domen, J. Am. Chem. Soc., 2009, 131, 13218-13219.
Electrochemical Dissolution in the Presence of Time Delayed Feedback
Authors: Organ Levent 
Published: February 2020

It is well known that time-delayed systems can exhibit rich dynamical behavior ranging from simple oscillations to high-dimensional chaos.[1, 2] Such systems are studied extensively in optoelectronic[3] and biological[4] systems. In electrochemical systems, time-delayed feedback can be used for the control of dynamics, e.g., for the stabilization of unstable steady states and periodic orbits[5]. In this study, the dynamical features of a prototype, negative differential resistance electrochemical model [6] is studied in the presence of various forms of delayed feedback. Specifically, the double layer potential drop is fed back with delay that is either discrete or in a distributed form using a delay kernel. In the latter case, the system was analyzed in a framework of an extended system of ordinary differential equations using an auxiliary variable. The behavior of the system at different parameter values is explored with a virtual space-time representation [7] technique. The features of various virtual spatial states in the form of rotating waves, cluster formation, and turbulence are discussed. Finally, comments are made on possibility of formation of virtual chimera states[8] in the electrochemical system with external delayed feedback.
References:
[1] Giacomelli, G., Marino, F., Zaks, M. A., Yanchuk, S., EPL, Vol. 99, 58005, 2012.
[2] Larger, L., Goedgebuer, J. P., Phys. Rev. E, 69, 036210, 2004.
[3] Larger, L., Proc. R. Soc. A, Vol. 371, 20120464, 2013.
[4] Bocharov, G., Rihan, F. A., J. Comp. and Appl. Math., Vol. 125, 183, 2000.
[5] Kiss, I.Z., Kazsu, Z., and Gaspard, V., Chaos, Vol. 16, 033109, 2006.
[6] Koper, M. T., M., Gaspard, P., J. Chem. Phys., 96, 7797, 1992.
[7] Arrecchi, F. T., Giacomelli, G., Lapucci, A., Meucci, R., Phys. Rev. A., Vol. 45, R4225, 1992.
[8] Larger, L., Penkovsky, B., Maistrenko, Y., Phys. Rev. Lett., Vol. 111, 054103, 2013.