bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Oxygen Evolution Reaction Activity of LaFeO3 with Co-Pi Decoration
Authors: Peng Qi , Wen Yanwei , Shan Bin , Chen Rong 
Published: February 2020

With the continuing energy demand and environmental deterioration by conventional coal and gasoline, it is urgent to develop renewable energy. Among many methods, water splitting to generate clean hydrogen fuels is among the most promising one. Many perovskites such as SrTiO3, NaTaO3 and AgNbO3 have become candidates materials for water splitting due to their high catalytic activity and flexible structures. However, the H2 production efficiency is relatively low at visible light regime because of the large band gap of most perovskite materials. From the view point of optical absorption, LaFeO3 with a band gap of 2.07eV [1] shall be a good candidate. Nonetheless, the poor oxygen evolution reaction (OER) performance of LaFeO3severely limits its water-splitting efficiency. To solve the problem, OER improvement is needed.
RuO2, IrO2 and Pt are the conventional OER catalyst [2-3], but they are of high cost. Co-Pi, an amorphous cobalt-phosphate-based material, is reported having a low over potential for OER in the phosphate buffer solution at pH 7~8[4] and its coating on hematite promotes the photoelecrochemistry performance effectively [5]. We report here the combination of the low cost Co-Pi with LaFeO3 to enhance the OER activity of LaFeO3. We demonstrate that an effective negative shift of 100meV for the onset potential with Co-Pi coating as OER improvement. The photoelectrochemical properties and its mechanism will also be discussed.
References:

K.M. Parida, Inter. J. of Hydrogen Energy, 35, 12161~12168 (2010).

E. Tsuji, A. Imanishi, K. I. Fukui, Y. Nakato, Electrochim.Acta, 56, 2009 (2011).

L. Ouattara, S. Fierro, O. Frey, M Koudelka, C. Comninellis, J. Appl. Electrochem, 39, 1361 (2009).

M. W. Kanan, D. G. Nocera, Science, 321, 1072–1075, 2008.

D. K. Zhong, D. R. Gamelin, J. Am. Chem. Soc, 131, 6086–6087,2009.
Lanthanum Activity, Activity Coefficients and Solubility in Gallium-Indium Liquid Alloys
Authors: Dedyukhin Alexander S. , Shchetinskiy Andrey V. , Volkovich Vladimir A. , Yamshchikov Leonid F. , Osipenko Alexandr G. 
Published: February 2020

Precipitation method is one of the simplest direct techniques for determining solubility of metals in liquid alloys. The main parameter influencing the separation of liquid and solid phases is their density. In our case the difference of densities of gallium-indium alloys and intermetallic compounds of lanthanum with gallium and indium is sufficient for separation of solid (intermetallic compound) and liquid phases during holding the supersaturated alloy at desired temperature. In the present study solubility of lanthanum was determined in binary Ga-In alloys containing 21.4 (eutectic), 40 and 70 wt.% In at 298–1081 K.
Time required for achieving equilibrium in Ga-In-La system was determined in a preliminary set of experiments. The experiments were performed at constant temperature with the samples of liquid alloys taken at certain time intervals. The amount of lanthanum added to the alloy exceeded its solubility limit. An example of the obtained results for Ga-40wt.% In alloy at 423 and 673 K is shown in Fig. 1. The minimum time needed for reaching constant La concentration was four hours and in the subsequent experiments this time interval was used as holding time between sampling the alloy.
Solubility of lanthanum in Ga-In eutectic alloy at 298–1081 K is shown in Fig. 2. The temperature dependence of lanthanum solubility has an inflection around 515 K which is most likely associated with increasing viscosity of the liquid alloy and difficulties in precipitating solid phase. Similar results were obtained for the alloys containing 40 wt.% indium at 428–983 K, Fig. 3, and 70 wt.% indium at 425–987 K, Fig. 4.
After each experiment the alloys were cooled to room temperature and intermetallic phases formed crystalline precipitates. The crystals were needle-shaped, from 2 to 8 mm in length. X-ray diffraction analysis showed that the precipitates consisted of two intermetallic phases, Ga3La and Ga6La. An example of the XRD pattern of the crystals precipitated from Ga-40 wt.% In based alloys is given in Fig. 5. The XRD patterns of the precipitates formed in Ga-21.4 wt.% In and Ga-70 wt.% In were similar.
Analysis of the samples showed that in all studied Ga-In systems (containing up to 70 wt.% In) only intermetallic compounds of lanthanum with gallium were formed irrespectively of indium content in the alloy, the only difference being in the ratio between Ga3La and Ga6La. Decreasing gallium content in the alloy resulted in increasing fraction of Ga3La intermetallic compound in the solid phase. Indium in the studied systems acted merely as an inert additive.
Ionic Liquid-Based Solvents for Natural Fiber Welding: Impact of Solvent System Composition
Authors: Brown E. Kathryn , Haverhals Luke M. , Fox Douglas M , De Long Hugh C. , Trulove Paul C. 
Published: February 2020

Certain ionic liquids (ILs) are known to be efficient solvents for biopolymers, in particular for cellulosic and silk based materials1. The ionic liquid solvent efficiency is strongly impacted by the presence of both impurities (e.g., water, residual reagents) and intentional additives (e.g., co-solvents or diluents)3,4. Natural fiber welding (NFW), the process of controlled partial dissolution and regeneration of biopolymers,5-7 is also affected by the presence of impurities and additives8.
In this work we investigate the impact of impurities and additives on NFW. The extent of NFW was characterized by x-ray diffraction, ATR-IR, SEM, and mechanical property testing. These data are correlated with solvent physical properties, such as viscosity, density, and surface tension, as well as with solvent properties as indicated by their Kamlet-Taft parameters.
For some of the systems investigated, there is a maximum solvent composition where polar aprotic solvents in conjunction with IL are more efficient at NFW than the IL alone. Surprisingly, this composition occurs when the mole ratio of IL to solvent is less than one to one. Understanding the factors that influence welding in these systems allows for greater control over the NFW process and facilitates the formation of functional biopolymer composite materials.

References

Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. J. Am Chem Soc, 2002, 124, 4974.

Phillips, D. M.; Drummy, L. F.; Conrady, D. G.; Fox, D. M.; Naik, R. R.; Stone, M. O.; Trulove, P. C.; De Long, H. C.; Mantz, R. A. J Am Chem Soc., 2004, 126, 14350.

Rinaldi, R. Chem. Commun., 2011, 47, 511.

Mazza, M.; Catana, D. A.; Vaca-Garcia, C.; Cecutti, C. Cellulose, 2009, 16, 207.

Haverhals, L. M.; Reichert, W. M.; De Long, H. C.; Trulove, P. C. Cellulose, 2010, 2985, 425.

Haverhals, L. M.; Sulpizio, H. M.; Fayos, Z. A.; Trulove, M. A.; Reichert, W. M.; Foley, M. P.; De Long, H. C.; Trulove, P. C.Cellulose, 2012, 19, 13.

Haverhals, L. M.; Nevin, L. M.; Foley, M. P.; Brown, E. K.; De Long, H. C.; Trulove, P. C. Chem.Commun., 2012, 48, 6417.

Haverhals, L. M.; Brown, E. K.; Foley, M. P.; De Long, H.; Trulove P. ECS Trans, 2012, 50, 6
Inkjet Printing Ionic Liquids for the Fabrication of Surface Structures on Biopolymer Substrates
Authors: Sweely Kurt D. , Fox Eric T. , Brown E. Kathryn , Haverhals Luke M. , De Long Hugh C. , Trulove Paul C. 
Published: February 2020

Inkjet printing has become an increasingly popular tool for materials science research due to its ability to rapidly create small devices with excellent precision and reproducibility. Recent studies have utilized inkjet printing for the construction of inexpensive devices using ink-mimicking solutions containing various materials of interest (magnetic, sensing, electronic)[i],[ii],[iii]. By varying the chemical nature of these inks, inkjet printing becomes a robust, versatile, and accessible tool for small scale material fabrication.
Ionic liquids (IL) have been the focus of materials research for some time due to their unique physical and chemical properties. Of significant interest is their ability to solubilize biopolymers such as cellulose and silk[iv]. When paired with inkjet printing, these ILs allow for variable, reproducible modification of biopolymers. By incorporating materials of interest into these IL inks, inkjet printing presents an extremely powerful tool for small scale fabrication with a myriad of applications. In this research we will discuss the modification of surface structures through the inkjet printing of neat IL, IL’s containing nano and micro-scale particles, and IL/polymer solutions.

[i] Delaney, J. T., Jr.; Smith, P. J.; Schubert, U. S. Inkjet Printing of Proteins. Soft Matter, 2009, 24, 4866.
[ii] Singh, M.; Haverinen, H. M.; Dhagat, P.; Jabbour, G. E. Inkjet Printing – Process and Its Applications. Adv. Materials, 2010, 22, 673.
[iii] Hu, C.; Bai, X.; Wang, Y.; Jin, W.; Zhang, X.; Hu, S. Inkjet Printing of Nanoporous Gold Electrode Arrays. Anal. Chem.
2012, 84, 3745.
[iv] Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. Dissolution of Cellulose with Ionic Liquids. J. Am. Chem. Soc., 2002, 18, 4974.
DFT Study of Oxygen Reduction Reaction on Pt-Zr Catalysts
Authors: Merinov Boris V , Tsai Ho-Cheng , Yu Ted H , Goddard William A 
Published: February 2020

The sluggish oxygen reduction reaction (ORR) kinetics at cathode and expensive Pt electrocatalysts are two main issues that retard fuel cell technology commercialization.1-3 To overcome these problems, alloying Pt with transition metals, core-shell structures, and non-Pt catalysts are applied to improve the catalytic activity and reduce the catalyst cost.4-8 It was found that Pt3Ni, Pt3Co, and Pt3Fe have better activity than pure Pt.9-11 However, stability of these alloys needs to be improved. Pt3Zr, Pt3Y, Pt3Sc show greater stability and high catalytic activity,9,10,12but these materials need further experimental and theoretical investigations.
We used DFT calculations to study the origins of the better ORR performance and greater stability of Pt-Zr catalysts. To accurately evaluate the activity of Pt-Zr catalysts, we examined binding energies of ORR intermediates and reaction energy barriers for ORR steps both in gas phase and solution. Based on the results obtained, ORR mechanisms on Pt-Zr catalysts will be considered and compared to pure Pt and Pt alloys. Some related experimental results will be discussed as well.

Acknowledgement. This work is financially supported by the National Science Foundation (grant CBET-1067848).

References

1. K. Kordesch and G. Simader, Fuel Cell and Their Applications, VCH: New York (1996).
2. R. P. O'Hayre, S. W. Cha, W. Colella and F. B. Prinz, Fuel Cell Fundamentals, John Wiley and Sons: New York (2006).
3. A. J. Appleby and F. R. Foulkes, Fuel Cell Handbook, Van Nostrand Reinhold: New York (1989).
4. R. Bashyam and P. Zelenay, Nature, 443, 63 (2006).
5. M. K. Debe, Nature, 486, 43 (2012).
6. R. Othman, A. L. Dicks and Z. Zhu, Int. J. Hydrogen Energy, 37, 357 (2012).
7. H. Yang, Angew. Chem. Int. Ed., 50, 2674 (2011).
8. B. Wang, J. Power Sources, 152, 1 (2005).
9. J. Greeley, I. E. L. Stephens, A. S. Bondarenko, T. P. Johansson, H. A. Hansen, T. F. Jaramillo, J. Rossmeisl, I. Chorkendorff and J. K. Norskov, Nat Chem, 1, 552 (2009).
10. V. Stamenkovic, B. S. Mun, K. J. J. Mayrhofer, P. N. Ross, N. M. Markovic, J. Rossmeisl, J. Greeley and J. K. Nørskov, Angew. Chem., 118, 2963 (2006).
11. V. R. Stamenkovic, B. S. Mun, M. Arenz, K. J. Mayrhofer, C. A. Lucas, G. Wang, P. N. Ross and N. M. Markovic, Nature materials, 6, 241 (2007).
12. S. J. Hwang, S. K. Kim, J. G. Lee, S. C. Lee, J. H. Jang, P. Kim, T. H. Lim, Y. E. Sung and S. J. Yoo, J. Am. Chem. Soc., 134, 19508 (2012).
New Spectroscopic Methods for Characterizing Single-Walled Carbon Nanotubes
Authors: Weisman R. Bruce , Streit Jason K. , Bachilo Sergei M. , Ghosh Saunab 
Published: February 2020

Many important photophysical properties of SWCNTs remain inadequately determined, including (n,m)-specific absorption cross sections, emissive quantum yields, and fluorescence action cross sections. A major challenge has been quantifying structure-specific SWCNT concentrations in dispersed mixed samples. We have used short-wave IR fluorescence microscopy to image and count individual nanotubes within known volumes of structurally sorted samples, thereby directly finding (n,m)-specific particle concentrations. Separate measurements of the length distribution and bulk absorbance then give absolute absorption cross sections per SWCNT carbon atom. We find cross sections that are inversely related to nanotube diameter. E11 cross sections are larger for mod 1 species than for mod 2, whereas the opposite pattern is found for E22 transitions.
We also describe a new experimental method, Spectral Analysis of Fluorescence Fluctuations (SAFF). Here, long sequences of millisecond-scale emission spectra are captured from dispersed SWCNT samples that are dilute and thin enough to show clear intensity variations reflecting statistical variations in the numbers of nanotubes inside the small probed volume. Unlike normal fluorescence correlation spectroscopy, the SAFF method is spectrally resolved. The set of sequentially measured spectra is analyzed to reveal relative abundances of (n,m) species, isolate emission spectra of single species from complex mixtures, and sensitively monitor the presence of small SWCNT aggregates through spectral cross-correlations.
Reference
J. K. Streit, et al., Nano Letters 14
, 1530 (2014).
Invited: Atmospheric-Pressure Plasmas Processes for Third Generation Photovoltaics
Authors: Mariotti Davide , Askari Sadegh , Mitra Somak , Svrcek Vladimir , Belmonte Thierry , Maguire Paul 
Published: February 2020

Non-thermal atmospheric pressure plasmas (APPs) have attracted great interest due the potential cost reductions in manufacturing and processing of materials for a wide range of applications [1]. Although APPs present several challenges, considerable progress has been achieved in recent years with an increasing number of industrial and commercial applications utilizing different forms of APPs. One of the most attractive application of APPs is for the synthesis and processing of nanomaterials with specific focus on materials for energy applications.
In this contribution we will present recent advances in both the synthesis and surface engineering of quantum confined silicon-based nanoparticles [2-5]. In particular we will discuss a range of synthesis methods that rely on atmospheric pressure plasmas for producing crystalline silicon nanoparticles as well as alloyed silicon-tin nanoparticles; these will include laser-produced plasmas, rf-APPs and plasmas in liquids. The analysis will include, in some of the cases, theoeretical models that highlight key mechanisms of nanoparticle heating [6].
We will then discuss the integration of silicon-based nanoparticles in photovoltaic devices, demonstrating their contribution as down-converters and/or as part of the active layer. In this context we will show how APP-based surface engineering can offer great opportunities for tailoring surface properties of the nanoparticles. Device parameters will be presented and analysed for different device architectures.
Finally, tha applicability of APPs in different aspect of photovoltaic device fabrication will be discussed presenting opportunities and challenges for large scale nanomanufacturing.

Acknowledgement

This work was partially supported by a NEDO project, the Royal Society International Exchange Scheme (IE120884), the Leverhulme International Network (IN-2012-136) and EPSRC (EP/K022237/1). DM also acknowledges the support of the JSPS Bridge Fellowship. SM and SA thank the financial support of the University of Ulster Vice-Chancellor Studentship.

References

[1] Mariotti D et al. J. Phys. D Appl. Phys. 43 (2010) 323001
[2] Mariotti D et al. Adv. Funct. Mater. 22 (2012) 954
[3] Švrček V et al. Appl. Phys. Lett. 97 (2010) 161502
[4] Švrček V et al. Chem. Phys. Lett. 478 (2009) 224
[5] Levchenko I et al. Carbon 47 (2009) 2379
[6] Askari S et al. Appl. Phys. Lett. submitted
Invited: Nanopartilce Composite Plasma CVD Films and Some Applications
Authors: Shiratani Masaharu , Koga Kazunori 
Published: February 2020

Nanoparticle composite films contains nanoparticles to tune optical, electrical, and mechanical properties of the films. Contribution of nanoparticles nucleated homogenously in reactive plasmas to formation of film structure is commonly discarded, because flux of nanoparticles to film surface is low and heterogeneous reactions on film surfaces are believed to determine predominantly the film structure. Here we overview nanoparticle formation in reactive plasmas [1] and then we show three examples in which nanoparticle flux can modify significantly film structure and hence film properties. The first example is a-Si:H. A-Si:H p-i-n solar cells show a performance degradation under prolonged light illumination. It is widely accepted that this effect is related to the creation of metastable defects. We have succeeded in depositing highly stable a-Si:H films using a multi-hollow discharge plasma CVD method by which the volume fraction of amorphous Si nanoparticles in films deposited in the upstream region is significantly reduced by driving clusters towards the downstream region [2, 3]. Conventional a-Si:H films contain a few % of amorphous Si nanoparticles in their volume, whereas our stable a-Si:H films contain less than 0.01%. The second example is Ge nanoparticle films. We report electrical power generation of Ge quantum-dot (QD) sensitized solar cells with rectification in a TiO2/Ge/polysulfide electrolyte system. We analyzes the effect of adding Sn in Ge films on device performance, where a band-gap Eg value of Ge1-xSnx alloys is tunable from 0.34 < Eg < 0.61 eV for Sn composition ratio x = 0.06 to 0.15[4,5]. The third example is porous low-k film. We have succeeded in depositing porous films with relatively high young modulus by depositing “isolated nanoparticles” [6]. Nanoparticles can be employed as another tuning knob of film structure control.
Work supported by MEXT, JSPS, JST, NEDO, and PVTEC.
[1] M. Shiratani, et al., J. Phys. D: Appl. Phys., 44, 174038 (2011).
[2] M. Shiratani, et al., MRS Proc. 1426 (2012) DOI:http://dx.doi.org/10.1557/opl.2012.1245.
[3] Y. Kim, et al., Thin Solid Films 523, 29 (2012).
[4] G. Uchida, et al., Jpn. J. Appl. Phys. 51, 01AD01 (2011).
[5] H. Seo, et al., Electrochim. Atca 87, 213 (2013).
[6] S. Nunomura, et al., Jpn. J. Appl. Phys., 44, L1509 (2005).
Application of Anodizing Method Templates for Electrochemical Capacitors
Authors: Park Soo-gil , Choi Jin-Kwon , Yi Hyeon-Seok , Kim Hongil , Kim Han-Joo 
Published: February 2020

Introduction

Lithium ion batteries (LIBs) and electro double layer capacitors (EDLCs) are regarded as electrical energy storage systems (ESS). LIBs are high energy density, but EDLCs have low energy density general information. The lithium ion capacitor (LIC) has advantages of LIBs and EDLCs. LIC has high energy density, high power density and high safety than LIBs. LIC comprises of a cathode electrode; active carbon, anode; graphitized carbon. It is similar to LIB and EDLC.
Porous anodic oxide films of aluminum (anodic porous alumina) have been widely investigated as nano templates and resist-films with good insulating properties for various micro and nano technology applications, such as magnetic recording media, electronic devices, biosensors, photonic crystals, micro lens arrays, plasmonic devices, three-dimensional microstructures and other basic nano-devices. When aluminum is anodized in appropriate acidic electrolytes, porous alumina develops, which exhibits a uniform array of hexagonal cells, each containing a uniform cylindrical nano-pore at the center.
In this study, we prepared carbon nano fibers (CNFs) by anodizing method on anodized alumina oxide (AAO) templates that were anodized in oxalic acid at 40V or phosphoric acid at 195V. These two types anodizing conditions determine the pore size of AAO and diameter of CNF. Mixture of anodic porous templates and PAA was carbonized in nitrogen at 600°C. The CNFs were heated up to 1400°C to increase the crystalline.

Experimental

We have discussed the effect of diameter change of CNFs on the electrochemical properties as an anode material in LICs. CNFs were prepared by carbonization using precursors with the polymer. Surface morphology of AAO templates and prepared CNFs were investigated by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The physical properties were performed by X-ray diffraction (XRD) and nitrogen gas adsorption measurements.
The electrode was prepared by slurry type. Electrochemical properties were evaluated that cyclic voltammetry (CV), electrochemical impedance spectroscope (EIS) and charge-discharge test.

Result & Discussion

Figure 1 shows the SEM images of Anodized Alumina Templates, (a) anodized at phosphoric acid, (b) anodized at oxalic acid
Figure shows SEM images of the AAO templates after pore-expansion treatment with 2nd anodized AAO templates at different electrolyte. The results of the electrolyte change bring result that change of pore size of AAO templates can be seen clearly. and we can prepared that the CNFs by AAO template shows a well-ordered diameter. The CNFs were heated up to 600, 1000, and 1400°C to increase the crystallite degree. As results, we confirmed that CNF has become platelet structure.