bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical and Thermal Catalytic Syntheses of Ammonia over Yttrium-Doped Barium Zirconate and Cerate Perovskites Supported Ruthenium Catalysts
Authors: Shimoda Naohiro , Kobayashi Yusuke , Kimura Yutaka , Satokawa Shigeo 
Published: February 2020

To resolve a global serious problem on energy consumption by human, the development of various new processes which a renewable energy and a surplus electric power generated from thermal and nuclear power plants are converted to the energy easy to handle is required. As one possible process, a technological process that electrical energy is convert to a chemical substance, so-called energy carrier, is raised. As a candidate of energy carrier, methylcyclohexane (MCH), ammonia (NH3), hydrogen peroxide (H2O2), formic acid (HCOOH) are considered in recent years. In the present work, we have paid attention to NH3. In other words, it is an electrolysis process to produce NH3 from the nitrogen contained in air and the hydrogen supplied by the electrolysis of water. For this electrochemical synthesis process, H2O or H2 is oxidized to proton at the anode, and proton is transported through the proton conducting electrolyte to the cathode. And then, N2 is reacted with proton and reduced to NH3 at the cathode. The lower the operation temperature, the more effective the electrolysis synthesis process of ammonia from N2 and H2O, compared with a conventional Harber-Bosch process. However, the development of solid electrolyte exhibiting high conductivity at lower temperature and the selection of electrode catalyst materials and electrode design to improve the reaction rate of ammonia synthesis for the cathode are required. Therefore, in this study, we have focused on the Ru based catalyst which is well known to be excellent catalysts for thermal catalytic synthesis of ammonia. Furthermore, Ba-Zr-Y and Ba-Ce-Y perovskite-type oxides exhibiting high proton conductivity have been used as a support material to improve the cell performance for electrochemical ammonia synthesis.
Firstly, the Ru/Ba-Zr-Y and/or Ba-Ce-Y perovskites solid catalyst was prepared, and its thermal catalytic property for ammonia synthesis was evaluated using a fixed bed flow reactor. As results of comparison tests, Ru/Ba-Zr-Y catalyst showed higher activity than Ru/Ba-Ce-Y catalyst. Furthermore, it was found that an addition of 10wt% of Y component to BaZrO3 perovskite enhances the catalytic performance significantly. And noted that Ru/Ba-Zr-Y catalyst exhibited higher performance than a conventional Ru-Cs+/MgO catalyst. Based on various characterization, we consider that electron transfer from Ba-Zr-Y perovskite to Ru species enhances the dissociation of N-N bond, leading to the high activity for ammonia synthesis. Additionally, in the present work, we have studied the effect of current loading to the catalyst on the catalytic performance for ammonia synthesis to evaluate the applicability of Ru/Ba-Zr-Y catalyst to an electrode catalyst.

Acknowledgments

This work was supported by CREST, Japan Science and Technology Agency.
Degradation of (La,Sr)(Co,Fe)O3-Δ SOFC Cathodes at the Nanometre Scale and below
Authors: Ni Na , Cooper Samuel , Skinner Stephen J. , Williams Robert , McComb David 
Published: February 2020

For developing solid oxide fuel cells operating at intermediate temperatures (ITSOFCs), metallic materials have become a preferential choice for the interconnect due to their low cost and excellent physical and chemical properties. However the presence of chromium in all commonly used metallic alloys has been found to cause poisoning of the cathode leading to rapid electrochemical performance degradation of the cathodes including one of the most promising (La,Sr)(Co,Fe)O3-δ (LSCF) perovskite oxides [1-3]. Despite the extensive research on the chromium deposition and poisoning processes, careful microstructural studies, especially at the nanoscale, are rare, which can provide valuable information for the fundamental understanding of the Cr poisoning mechanisms required for developing Cr tolerant cathode materials.
In this paper, we examine the Cr poisoning mechanisms in (La0.6Sr0.4)0.95(Co0.2Fe0.8)O3-δ (LSCF6428) materials by correlating the bulk electrochemical properties of the cell with their structural and chemical change at multi-scales down to the nanometer level. Cells with LSCF cathodes were prepared, and the effect of Cr poisoning on the electrochemical behavior of the cell was assessed by impedance spectroscopy. The change in nano/microstructure and chemistry due to poisoning were studied in parallel by a combination of advanced ion and electron microscopy techniques including focus ion beam (FIB) tomography, high resolution (scanning) transmission electron microscopy ((s)TEM) and analytical STEM.
The systematic combination of bulk and high-resolution analysis on the same cells allows, for the first time, to directly correlate Cr induced performance degradation with subtle and localized structural/chemical changes of the cathode down to the atomic scale. Up to two orders of magnitude reduction in conductivity, oxygen surface exchange rate and diffusivity were observed in Cr poisoned LSCF6428 samples. These effects are associated with the formation of nanometer size SrCrO4; grain boundary segregation of Cr; enhanced B-site element exsolution (both Fe and Co); and reduction in the Fe valence, the latter two being related to Cr substitution in the LSCF phase. The finding that significant degradation of the cathode happens before obvious microscale change points to new critical SOFC degradation mechanisms effective at the nanometer scale and below, which provide new insight for the development of future poisoning resistant electrode materials not only for SOFCs but also for other devices such as solid oxide electrolysis cells.

References

[1] M.C. Tucker, H. Kurokawa, C.P. Jacobson, L.C. De Jonghe, S.J. Visco, J. Power Sources 160 (2006) (1) 130.
[2] S.P. Jiang, X.B. Chen, Int. J. Hydrog. Energy 39 (2014) (1) 505.
[3] S.N. Lee, A. Atkinson, J.A. Kilner, J. Electrochem. Soc. 160 (2013) (6) F629.
Ab Initio Calculations of Ionic Conductivity in Lithium and Sodium Polyborate Solid Electrolytes
Authors: Wood Brandon C. , Varley Joel , Kweon Kyoung , Stavila Vitalie , Udovic Terrence John 
Published: February 2020

A subset of alkali polyborates have recently been identified as highly promising solid electrolytes for next-generation batteries due to their superionic transition temperatures approaching room temperature and ionic conductivities exceeding 0.1 S/cm–1. However, the exact mechanisms driving the transport in these materials remain largely unknown. Here we use large-scale ab initio molecular dynamics calculations to characterize the diffusivity of the Li and Na species in a representative set of B12H12- and B10H10-based closoborane ionic conductors, focusing on the role of stoichiometry, volume, and dopant incorporation in enhancing ionic conductivity. Detailed analysis on representative materials is used to elucidate the specific conduction mechanism, which relies on frustrated competition between longer- and shorter-range interionic interactions. Our results support this class of materials as highly promising solid electrolytes and offer insights that can be used to tailor conductivity and stability for their use in next-generation battery technologies.
This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Na10TiP2Se12 As Novel Electrolyte for All-Solid-State Na-Battery
Authors: Zhang Dehui , He Liqing , Wu Dong , Lu Zhouguang 
Published: February 2020

All-solid-state battery has the advantages of high safety, good stability and simple configuration [1]. To develop electrolytes with outstanding ion conductivity and stable and wide electrochemical window is indispensible for eventually commercial application of all-solid-state batteries [2,3]. Up to now, many kinds of solid electrolytes have been successfully prepared [4]. Herein, we designed and synthesized a novel kind of solid electrolyte material of Na10TiP2Se12 by a simple low temperature solid state method. The as synthesized Na10TiP2Se12 shows brown in color and exhibits a completely new structure (as shown in Figure 1) different from all raw materials which means the successful synthesis. The ionic conductivity of the as synthesized Na10TiP2Se12 at room temperature is determined to be 6.17×10-7S/cm by preliminary AC impedance measurement. Experiment conditions have been optimized to further improve the conductivity and stability of this solid electrolyte.

Acknowledgements

This work was financially supported by the Shenzhen Peacock Plan (KQCX20140522150815065)，the Natural Science Foundation of Shenzhen ( JCYJ20150331101823677) and the Science and Technology Innovation Foundation for the Undergraduates of SUSTC(2015x19 and 2015x12)

Reference

[1]Etacheri V, Marom R, Elazari R, et al. Challenges in the development of advanced Li-ion batteries: a review [J]. Energy & Environmental Science, 2011, 4(9): 3243-3262.
[2]He L, Li H W, Nakajima H, et al. Synthesis of a bimetallic dodecaborate LiNaB12H12 with outstanding superionic conductivity[J]. Chemistry of Materials, 2015, 27(16): 5483-5486.
[3]Richards W D, Tsujimura T, Miara L J, et al. Design and synthesis of the superionic conductor Na10SnP2S12[J]. Nature Communications, 2016, 7.
[4]Solid electrolytes: general principles, characterization, materials, applications[M]. Elsevier, 2015.

Figure 1
A Novel Solid Electrolyte Material (Li17Ge2P3S20) with High Ionic Conductivity
Authors: Wu Dong , He Liqing , Zhang Dehui , Lu Zhouguang 
Published: February 2020

Organic liquid compound electrolytes are widely applied in conventional lithium-ion batteries. However, their disadvantages of unsafety and complexity of battery fabrication can hardly be avoided [1]. All-solid-state batteries without using liquid electrolytes provide an effective way to overcome these problems and studies on this field are increasing [2]. Solid electrolyte material is the critical factor to affect the electrochemical and cycle performances of all-solid-state batteries. For commercial application of all-solid-state batteries, high ionic conductivity and cyclability at room temperature are indispensable. Metal sulfides are in great potential to meet the practical application as solid electrolytes and a series of solid sulfur compounds with high ionic conductivities have been reported [3,4]. In this work, a new material Li17Ge2P3S20 with new crystal structure has been synthesized via a simple solid state reaction. The new structure is detected using XRD patterns as shown in Figure 1. AC impedance has been performed and the ionic conductivity of Li17Ge2P3S20 is determined to be 8.07×10-3 S/cm at room temperature. Experimental parameters have been optimized and elemental doping has been utilized to enhance the conductivity and stability of this material as solid electrolyte for all-solid-state lithium ion batteries.

Acknowledgement

This work was financially supported by the Shenzhen Peacock Plan (KQCX20140522150815065)，the Natural Science Foundation of Shenzhen ( JCYJ20150331101823677) and the Science and Technology Innovation Foundation for the Undergraduates of SUSTC(2015x19 and 2015x12)

References:

[1] Etacheri V, Marom R, Elazari R, et al. Challenges in the development of advanced Li-ion batteries: a review[J]. Energy & Environmental Science, 2011, 4(9): 3243-3262.
[2] Notten P H L, Roozeboom F, Niessen R A H, et al. 3‐D integrated all‐solid‐state rechargeable batteries[J]. Advanced Materials, 2007, 19(24): 4564-4567.
[3] Kamaya N, Homma K, Yamakawa Y, et al. A lithium superionic conductor[J]. Nature materials, 2011, 10(9): 682-686.
[4] Kato Y, Hori S, Saito T, et al. High-power all-solid-state batteries using sulfide superionic conductors[J]. Nature Energy, 2016, 1: 16030.

Figure 1
Influence of Solid Electrolyte Interphase Stabilization on Cycling Performance of Silicon-Graphite Composite Battery Anodes
Authors: Kim Jaeram , Jo Hyuntak , Nguyen Dan Thien , Jeon Do-Man , Yang A-Reum , Song Seung-Wan 
Published: February 2020

Silicon-graphite composites have drawn significant attention as promising anode materials for higher energy density Li-ion batteries due to larger theoretical specific capacity of silicon than currently commercialized graphite.1 They, however, suffer from a large volume change during lithiation and delithiation, causing the particle cracking, structural degradation of the electrode, an instability of the solid electrolyte interphase (SEI) and finally leading to poor cycle life. In order to address the problems, several strategies in the aspects of improved electrical conductivity and buffering effect of volume change have been developed but the fabrication of silicon composites with carbon materials combined with the use of functional binder and electrolyte additives 2-
4 are recognized as a promising approach. In this presentation, we report the control of electrode-electrolyte interfacial reaction and the formation of a stable SEI layer using various additives, and SEI characterization using ATR FTIR spectroscopy combined with X-ray photoelectron spectroscopy.
In the conventional electrolyte of 1M LiPF6/EC:EMC (3:7 volume ratio), the half-cell with Si-graphite composite anode, which is cycled between 0.01 and 1.5 V at the rate of 0.2C, shows a rapid capacity fade and a low capacity retention of 68 % at the 50th cycle. On the contrary, the cell with the designed blended additives yields improved capacity retention to 81 %, with well-maintained coulombic efficiency of higher than 99 %. Further studies of additive-dependent SEI composition and stability and their correlation to cycling performance would be discussed in the meeting.

Acknowledgements

This research was supported by the Korean Ministry of Trade, Industry & Energy (10049609), and Nano-Material Technology Development Program by the Ministry of Science, ICT and Future Planning (2009-0082580).

References

1. Y. Zhang, X.G. Zhang, H.L. Zhang, Z.G. Zhao, F. Li, C. Liu, and H.M. Cheng, Electrochim. Acta, 51, 4994 (2006).
2. S.-W. Song. and S.-W. Baek, Electrochem. Solid-State Lett.,
12, A23 (2009).
3. J.-S. Kim, C. C. Nguyen, H.-J. Kim, and S.-W. Song, RSC Adv., 4, 12878 (2014).
4. D. T. Nguyen, J. Kang, K. M. Nam, Y. Paik, and S. W. Song, J. Power Sources, 303, 150 (2016)
Fabrication and Evaluation of Silver-Indium Catalysts for Electrochemical CO2 Reduction to CO
Authors: Park Hyanjoo , Choi Jihui , Kim Hoyoung , Hwang Eunkyoung , Ha Don-hyung , Paik Taejong , Ahn Sang Hyun , Kim Soo-Kil 
Published: February 2020

CO2 has been one of the problematic greenhouse gases, and there have been a lot of efforts to reduce it through capturing, storage, and conversion [1,2]. Ultimately, CO2 needs to be reduced to high energy state fuels including CO. However, CO2 is stable molecule and requires high potential for electrochemical reduction process. Also, hydrogen evolution reaction (HER) occurs at similar potential, thus a selective catalytic reduction is essentially required for electrochemical reduction of CO2 to fuels, in this case CO [3]. So far, Au and Ag catalysts have been studied extensively as candidate catalysts for CO production [4]. Even though Au has provided slightly higher activity, Ag is continuously suggested as a reliable candidate with cost effectiveness.

In this work, we developed AgIn catalysts through co-deposition method. It has been known to have large overpotential to HER, which will improve the selectivity of Ag in production of CO over H2. The co-electrodeposition was done through controlling the ratio of amounts of In and Ag precursors in the deposition bath. The fabricated catalysts were analyzed through FE-SEM for surface analysis, EDS to find out Ag and In composition, and XRD to identify the crystal structure and degree of alloy. Also, chronoamperometry (CA) was used to measure and calculate CO2 reduction efficiency using home-made H type cell. Gas chromatography (GC) was used to analyze produced amounts of CO. The results showed that AgIn catalysts was deposited in dendritic morphology and showed much better CO faradaic efficiency than Ag only catalysts.

Reference
1. Lu, Q.; Rosen, J.; Zhou, Y.; Hutchings, G. S.; Kimmel, Y. C.; Chen, J. G.; Jiao, F. Nat Commun
2014, 5.
2. Rosen, J.; Hutchings, G. S.; Lu, Q.; Rivera, S.; Zhou, Y.; Vlachos, D. G.; Jiao, F. ACS Catalysis
2015, 5, 4293.
3. Hall, A. S.; Yoon, Y.; Wuttig, A.; Surendranath, Y. Journal of the American Chemical Society
2015, 137, 14834.
4. Zhou, L. Q.; Ling, C.; Jones, M.; Jia, H. Chemical Communications
2015, 51, 17704.
Electrochemical Conversion of Carbon Dioxide on the Exfoliated Single-Crystal Copper Membranes
Authors: Yoshihara Naoki , Noda Masaru 
Published: February 2020

The electrochemical conversion of carbon dioxide (CO2) enables to produce hydrocarbons, which are widely utilized as fuels or industrial feedstock, at ambient pressure and room temperature. In addition, due to the improved power generation technology using renewable energy sources such as solar and wind, CO2 electrochemical conversion has attracted a great deal of interest as a novel technique to realize a sustainable carbon cycle [1-2]. In our previous work, single-crystal copper membranes were prepared by sputtering on specific support substrates such as c-plane sapphire or magnesium oxide [3]. CO2 conversion on our crystalline copper membranes evolved hydrocarbons more favorably than on commercial copper plates. However, a surface of such epitaxially grown copper membranes is no atomically flat. For CO2conversion into hydrocarbons effectively, the electrode of high quality and smooth single-crystal copper is required.
In this work, CO2electrochemical conversion was studied on the single-crystal copper membranes peeled off from a support substrates.In the experiments, single-crystal copper membranes used as the working electrode (WE) were deposited onto c-plane sapphire substrates with a power of 200 W at 200 °C by radio frequency magnetron sputtering (RFS-200S, ULVAC Corp., Japan) for 5 hr. The copper membranes deposited onto c-plane sapphire were identified as Cu(111) by XRD measurement. The crystalline copper membrane is able to be peeled away from a support substrate.
Figure 1 shows cyclic voltammograms on the exfoliated single-crystal copper membranes in the CO2-saturated 0.25 M K2HPO4+KH2PO4 electrolyte at a scan rate of 10 mV/s. In topside of the exfoliated copper membrane faced on a surface of c-plane sapphire, a significant decrease in current density started from −0.5 V vs. RHE, while those on backside started from −0.6 V vs. RHE. This suggests that an activity of CO2electrochemical conversion was contributed the surface smoothness of a copper membrane in addition to that of the crystallinity.
We also show hydrocarbon emissions for CO2conversion on the exfoliated single-crystal copper membranes, and the electrochemical mechanism based on carbonate ions concentration in the electrolyte is discussed.

Acknowledgement

This work is supported by the Shiraishi Scientific Research Grant.

Reference

[1] Y. Hori, I. Takahashi, O. Koga, and N. Hoshi, Journal of Molecular Catalysis A: Chemical, 199, 39–47 (2003).
[2] K. J. P. Schouten, E. P. Gallent, and M. T. M. Koper, ACS Catal., 3(6), 1292–1295 (2013).
[3] N. Yoshihara, M. Arita, and M. Noda, ECS Transactions, 66(24), 83-89 (2015).

Fiugre 1 Cyclic voltammograms for CO2 conversion on topside and backside of the single-crystal copper membranes peeled off from the c-plane sapphire substrates in the CO2-saturated 0.25 M K2HPO4+KH2PO4electrolyte.

Figure 1
NO Electrochemical Reduction on Pt Electrocatalysts: A DFT Approach
Authors: Chun Hee-Joon , Apaja Vesa , Honkala Karoliina , Greeley Jeff 
Published: February 2020

Electrochemical denitrification is a promising technology for the removal of toxic nitrate and nitrite species from groundwater due to the process’s environmental compatibility, energy efficiency, safety, and product selectivity[1]-[3]. The adsorbed NO is generally considered to be a selectivity-determining species during this electrochemical potential-dependent reaction[4], [5]. Atomic-scale studies using density functional theory (DFT), in turn, can provide powerful molecular-level information about the elementary mechanisms of reductive NO electrocatalysis, and these basic building blocks can further serve as a starting point for future trends-based analysis on different transition metal surfaces.
In this work, we employ periodic, self-consistent DFT calculations to clarify the adsorption structures and thermochemistry of NO and its related reaction intermediate species on different Pt single crystal surfaces ((111) and (100)). Kinetics are further determined by calculating the activation barriers for N-O dissociation, protonation, and N-N bond formation. We begin by describing results for the reaction at low NO coverage (ca. 0.11 ML). After describing the thermodynamics (the adsorption) and kinetics (N-O bond breaking and protonation barrier) for the dentirification reaction scheme, a plausible mechanistic reaction pathway is proposed. Water-assisted protonation barriers are generally shown to be lower than barriers for non-electrochemical reactions, such as surface hydrogenation or N-O bond breaking[6]. Consistent with available experimental evidence, from the most probable reaction pathway, we conclude that ammonium ion would be the most favorable product that would evolve. There is no evidence for the formation of hydroxylamine (H2NOH) at low coverage. At higher NO coverages (ca. 0.45 ML), the relative energy states of the intermediates show a similar trend for the energetics when it is compared with the study with lower NO coverage. Next, N2O formation is examined. We find that trans-(NO)2 species could be a precursor state for the N­2O formation due to its lower kinetic barrier than barriers that are found for cis-type NO dimers. The simulation demonstrates that N2O could be formed at higher potentials through two protonations of trans-(NO)2 species, and the reaction is thermodynamically more favorable at higher NO coverage. This barrier could be surmountable at room temperature, and these mechanistic conclusions hold on both the (111) and (100) surfaces.
Finally, using the DFT results to determined rate constants, we construct a detailed kinetic Monte Carlo model of the overall NO electroreduction network. The model accurately tracks experimental NO stripping curves and provides estimates of the degrees of rate control of elementary reaction steps.