bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Reduction of Hydrogen Carbonate Using Porous Diodes
Authors: Chipangura Yevedzo E , Chaparadza Allen 
Published: February 2020

The electrochemical reduction of CO2 on metal electrodes is an intensively studied reaction. However, there has not been much attention for CO2reduction on photo based diodes. Aqueous hydrogen carbonate is carbon dioxide equivalent:
H2O +CO2 ↔ H2CO3 ↔ HCO3
- + H+ ↔ CO3
2-+ 2H+

Here we report the electrochemical reduction of aqueous of hydrogen carbonate to formate using porous diodes fabricated using platinum deposited Sb doped SnO2 (n-type) and Li doped CuO (p-type) nanowires. XRD, TEM and ATR-UV-Vis were employed to characterize the nanowires. Typical current-voltage curves of such devices resemble the behavior of a typical diode except for one key difference; the areas near the p-n interface and the p-and n-regions are accessible to analytes. Photo electrochemical reduction efficiency measurements were measured using cyclic voltammetry, as a function of UV light intensity and wavelength. GC, HPLC, NMR and IR were used to quantitatively and qualitatively analyze the reduction products. 13C enriched hydrogen carbonate NMR and infrared spectroscopy confirmed the reduction of hydrogen carbonate to formate. The reduction rate of hydrogen carbonate was 0.0015 mol min-1 cm-2at a bias voltage of 1.65 V. The rate of reduction decreased with increasing lithium doping up to 20% and increasing antimony up to 10% (moles in synthesis) with respect to copper and tin respectively.

Figure 1
Metal Extraction Driven By Galvani Potential at the Interface Between Two Immiscible Electrolyte Solutions
Authors: Murtomäki Lasse , Nieminen Eemi 
Published: February 2020

In an immiscible water-oil system, potential determining salts can be applied to establish Galvani potential across the interface (ITIES). These salts contain a common ion in the both phases and, therefore, via a Nernstian equation, determine the Galvani potential difference that can be used to boost electron or ion transfer reactions across the ITIES [1,2].
The contribution of potential difference and potential determining salts to solvent extraction of various metals (Co, Cu, Ni, In) was investigated with cyclic voltammetry (CV) in a four-electrode cell and with shake-flask experiments; the extraction ratios were analyzed either by atomic absorption spectroscopy (AAS) or by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Di-2-(ethylhexyl)-phosphoric acid (D2EHPA) and diphenylthiocarbazone (Dithizone) were used as model ligands. While CV measurements showed ambiguous results - sometimes no ion transfer within the potential window was observed - shake-flask experiments showed clearly that the extraction ratio (co
/cw
) of some metals is enhanced in the presence of potential determining salts (Fig. 1).

Fig. 1. The contribution of the potential determining salt to the extraction ratio of Ni in pH 3 and 5.

[1] P. Peljo, L. Murtomäki, T. Kallio, H.-J. Xu, M. Meyer, C. P. Claude, J.-M. Barbe, H. H. Girault, K. Laasonen, K. Kontturi, Biomimetic Oxygen Reduction by Cofacial Porphyrins at a Liquid-Liquid Interface, J. Am. Chem. Soc., 134, 5972-5984, 2012.
[2] B. Su, R. Partovi-Nia, F. Li, M. Hojeij, M. Prudent, C. Corminboeuf, Z. Samec and H. H. Girault, H2O2 Generation by Decamethylferrocene at a Liquid|Liquid Interface, Angew. Chem., Int. Ed., 47, 2675-4678, 2008.

Figure 1
Electroswitchable Emission and Coloration Based on Single-Molecular Fluoran Derivatives
Authors: Nakamura Kazuki , Kanazawa Kenji , Kobayashi Norihisa 
Published: February 2020

Multifunctional molecular switches exhibiting changes in both emission and coloration in response to various external triggers such as thermal, photo, and electric stimuli have attracted much attention for potential application as chemical sensors, biochemical labels, molecular logic gates, molecular memories, and display devices. In this study, we demonstrated reversible electrochemically induced high-contrast switching of the emission and coloration of fluoran molecules associated with changes in the intramolecular structure.
In order to investigate changes in the photophysical properties induced by electrical stimuli, we measured cyclic voltammogram, absorption spetra, emission spectra, and molecular orbital calculation. The mechanism for this electroswitching was attributed to the reversible electrochemically induced closing and opening of the lactone ring in the fluoran molecule. All neutral fluoran molecules were colorless and did not exhibit any fluorescence, while the oxidized (lactone ring-opened form) molecule was yellow and displayed a green fluorescence as a consequence of the extended, planar, conjugated system. Furthermore, this fluoran molecule achieved reversible electroswitchable emission and coloration with high on/off contrast[1].
In order to achieve a quick response time and high reversibility of the electroswitching optical device for modulating both emission and coloration, a 1,4-benzoquinone (BQ) molecule was introduced as a bifunctional material. The inclusion of a redox-active moiety on the auxiliary electrode maintained the charge balance and acted as an EC molecule (transparent/yellow in neutral/reduced state, respectively). BQ acted as a bifunctional molecule, leading to quick and stable switching of both emission and coloration[2].

Reference

[1] K. Kanazawa, K. Nakamura and N. Kobayashi, J. Phys. Chem. A, 118, 6026–6033 (2014).
[2] K. Kanazawa, K. Nakamura and N. Kobayashi, Sol. Ener. Mater. Solar Cell., 145, 42-53 (2016).

Figure 1
Electroactive, Multisensitive Nanocomposite. Electrocatalytic Activity and Attachement to Gold Electrode Surface
Authors: Mackiewicz Marcin , Karbarz Marcin , Romański Jan , Stojek Zbigniew Jan 
Published: February 2020

Microgels are chemically cross-linked polymers with a network structure that are colloidal in size and swollen in a suitable solvent.1 Environmentally sensitive gels: “smart” nanogels sensitive to external stimuli such as temperature, pH, ionic strength, presence of specific ions, solvent composition and electromagnetic radiation can react quickly to environment changes.2 However, plain smart hydrogels are generally electrically nonconductive, while conductivity is required in such applications as supercapacitors, fuel cells and sensors.3 Our aim was to fabricate a new conductive multiple stimuli-responsive hybrid nanocomposite consisting of nanogel p(NIPA-BISS), AuNP’s and polyaniline (PANI). A combination of polymeric hydrogel and PANI-Au led to the materials that exhibited the properties characteristic for both components. We obtained thermally- and pH responsive, electroactive and conductive hybrid nanocomposites with good catalytic properties. We deposited them on the gold-electrode surface. The nanocomposite consisted of a nanogel containing disulfide groups in the crosslinkers to make possible its attachment to the gold-electrode surface and polyaniline nanofibers with embedded in them gold nanoparticles. The presence of polyaniline in the composite nanoparticles led to a substantial increase in conductivity and electroactivity of the nanogels and allowed elimination of aggregation of nanocomposites in acidic solutions at increased temperature. In the first step of synthesis, p(NIPS-BISS) nanogel, based on poly(N-isopropylacrylamide) cross-linked with N,N’-bisacryloylcystine, was prepared via surfactant-free emulsion polymerization (SFEP). Next, by soaking the nanogel with a solution of an oxidizing agent (chloroauric acid, HAuCl4) and placing the soaked gel in a solution of aniline in nitrobenzene, the conducting polymer and AuNPs were formed in p(NIPA-BISS) nanogel. The structure, morphology and swelling behavior of the nanogels were investigated using SEM, TEM and DLS. To evaluate the state of PANI oxidation the Raman spectroscopy was used. The electrocatalytic oxidation of ethanol at gold electrodes covered by the nanocomposites was examined using voltammetry.
This work was supported by a grant from the National Science Centre of Poland, Preludium 8, 2014/15/N/ST5/02937

1. B. R. Saunders, B. Vincent, Adv. Colloid Interface Sci., 1999, 80, 1.
2. Maćkiewicz, M.; Romański, J.; Karbarz, M. New Ampholytic Microgels Based On N-Isopropylacrylamide And Α-Amino Acid: Changes In Swelling Behavior As A Function Of Temperature, Ph And Divalent Cation Concentration. RSC Adv.
2014,4, 48905- 48911.
3. Zhai, D.; Liu, B.; Shi, Y.; Pan, L.; Wang, Y.; Li, W.; Zhang, R.; Yu, G. Highly Sensitive Glucose Sensor Based On Pt Nanoparticle/Polyaniline Hydrogel Heterostructures. ACS Nano
2013, 7, 3540-3546.

Figure 1
Selective Reversible Absorption of the Industrial Off-Gas Components CO2 and NOx by Ionic Liquids
Authors: Kaas-Larsen Peter Kjartan , Thomassen Peter , Schill Leonard , Mossin Susanne , Riisager Anders , Fehrmann Rasmus 
Published: February 2020

Ionic liquids are promising new materials for climate and pollution control by selective absorption of CO2 and NOx in industrial off-gases. In addition pratical cleaning of industrial off gases seems to be attractive by use of ionic liquids distributed on the surface of porous, high surface area carriers in the form of so-called Supported Ionic Liquid Phase (SILP) materials. The potential of selected ionic liquids for absorption of CO2 and NOx will be demonstrated and the possible mechanism of absortion will be described on the molecular level. Our vision of application of these ionic liquids in the form of SILP filters to flue gas cleaning in power plants, waste incineration plants, cement and glass factories as well as unborad ships will be adressed.
Influence of Electrode Gas Flow Rate and Electrolyte Composition on Thermoelectric Power in Molten Carbonate Thermocell
Authors: Kandhasamy Sathiyaraj , Calandrino Luca , Burheim Odne Stokke , Solheim Asbjørn , Kjelstrup Signe , Haarberg Geir Martin 
Published: February 2020

A thermo-electrochemical cell (thermocell) is an electrochemical system with two identical electrodes placed at different temperatures in an electrolyte solution. The ion migration between the electrodes due to the temperature gradient leads to thermoelectric conversion. Such systems represent a promising pathway to utilise dynamic heat as power source. A possible thermo-electrochemical cell with molten carbonate electrolyte and gas electrodes was recently reported [1,2]. The change in Seebeck coefficient (thermoelectric power) with electrode materials, electrode gas mixture, electrolyte composition and electrolyte support materials was studied [2]. Addition of support material (solid oxide) in the molten carbonate electrolyte, may reduce the thermal conductivity and maintain the temperature gradient between the electrodes. Thermal boundary layers may arise due to the electrode gas flow; slow flow rate seems to be preferred for obtaining a high value in thermoelectric power. In this study the system is further optimised with respect to the composition of electrolyte and supporting materials as well as electrode gas flow rate. The thermoelectric power is measured with various ratios of ((Li,Na)2CO3) molten carbonate to support (MgO) solid oxide in the electrolyte mixture and also with different gas flow rates at the electrode-electrolyte interface.

References

1. M.T. Borset, X. Kang, O.S. Burheim, G.M. Haarberg, Q. Xu, S. Kjelstrup, Electrochimica Acta 182 (2015) 699 - 706.
2. X. Kang, M.T. Børset, O.S. Burheim, G.M. Haarberg, Q. Xu, S. Kjelstrup, Electrochimica Acta 182 (2015) 342 - 350.
The Effect of Lengthening Cation Ether Tails on Ionic Liquid Properties
Authors: Lall-Ramnarine Sharon , Rodriguez Chanele , Fernandez Rahonel , Zmich Nicole , Fernandez Eddie , Dhiman Surajdevparkash , Wishart James F. 
Published: February 2020

Ionic liquids (ILs) are attractive alternative solvents in a variety of applications such as in supercapacitors, batteries, solar energy conversion and for the storage and clean-up of nuclear waste. However, their high viscosities impede their adoption in many large scale processes. Ether side chains have been shown to lower the viscosity of ILs. In this work, we have synthesized a series of ten pyrrolidinium ionic liquids and ten imidazolium ionic liquids bearing ether and alkyl side chains of varying lengths (4 to 10 atoms in length). Their physical properties, such as viscosity, conductivity and thermal profile were measured and compared. Results reveal a dramatic decrease in viscosity with the substitution of alkoxy (ether) side chains for alkyl side chains on the pyrrolidinium cation. However, as the length of the ether chain increases there is negligible change in the viscosity (of about 50 cP). In contrast, a consistent increase in the viscosity was observed as the length of the alkyl side chain increases. Preliminary results of the imidazolium series show a similar trend. These results provide significant insight on the choice of starting materials for researchers designing ILs for specific applications. The work at BNL was supported by the BNL Office of Educational Programs and the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under contract DE- SC0012704.
Electrochemical Synthesis of LaSi2 from a NaCl-Naf-LaF3-K2SiF6 Melt at 1023 K
Authors: Kochetova Svetlana , Savchuk Ruslan N , Pisanenko Alexandr Dmitrievich , Devyatkin Sergei Vladimirovich 
Published: February 2020

Lanthanum silicides (La5Si4, La5Si3, La4Si, LaSi and LaSi2) are metal-like compounds with semiconductor properties. If this were true, it could become technologically important as an infrared detector material [1]. The possibility of electrochemical synthesis of lanthanum silicides from molten salts were investigated in this work. It can be concluded from thermodynamic calculation that silicon discharge from molten salts more positive than La (~ 0.8 V), in this case electrochemical synthesis possible only in two step, first deposited of Si, next step deposition of La onto Si with formation of lanthanum disilicide:
I. 2Si + La(III) +3 e = LaSi2 ΔE0
10233 K = ΔG0
1023 K/ (nF) ≈ 0.500 V,where ΔE0 – is potential (V), ΔG0
- is the Gibbs energy of the reaction I. (J), n – is the number of electrons involved in the reaction (in our case, n = 3), F – is Faraday constant.
The electrochemical behaviour of the molten salts system NaCl-NaF-LaF3-K2SiF6 was studied by cyclic voltammetry. A glassy carbon crucible served as a vessel for the melt and as an auxiliary electrode; a W wire was used as the working electrode; the measurements were made with respect to glassy carbon reference electrode 1023 K in argon atmosphere. Typical cyclic voltammogram for molten salts system NaCl-NaF-LaF3-K2SiF6 show two step process of electrochemical synthesis of LaSi2at 1023 K in Ar on W working electrode (Fig. 1 .).
On the base of thermodynamic calculation and voltammetric investigation, it has been show that lanthanum disilicide can by electrochemical synthesized from a NaCl-NaF- LaF3-K2SiF6
melt at 1023 K in two step. References

R.G. Long, M.C. Bost, J.E. Mahan., Appl. Phys. Lett. 5
3, 1272 (1988).

Fig. 1. Voltammogram of a NaCl-NaF-LaF3- K2SiF6 melts on a W working electrode, v= 0.1 V/s.

Figure 1
Porous Ionic Liquids: Challenges and Opportunities
Authors: Dai Sheng 
Published: February 2020

Functional materials using or in the presence of ionic liquids represents a burgeoning direction in materials chemistry. Ionic liquids are a family of non-conventional molten salts that can act as both functional materials and solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility of both organic and inorganic molecules, and ion conductivity. The unique solvation environment of these ionic liquids provides new reaction and separation media for controlling many energy-related processes. We have recently developed a class of ionic liquids with intrinsic porosities based on nanoscopic building blocks. Challenges and opportunities in synthesizing and using these porous ionic liquids in energy-related applications will be discussed.
Aqueous Solid-Liquid Interfaces at Atmoci Scale
Authors: Lopes Pietro Papa , Strmcnik Dusan , Markovic Nenad M , Stamenkovic Vojislav 
Published: February 2020

Atomic scale insight at the aqueous electrified solid-liquid interfaces is considered critical in further advancement of materials that could be implemented in electrochemical systems such as electrolyzers, batteries and fuel cells. The research effort aimed to fundamental understanding of processes that are relevant for energy conversion, storage and biomedical applications will be presented.
It has been demonstrated that fine tuning of the material properties can lead towards unprecedented improvements in their functional properties [1]. This presentation will address unique research approach that is capable of revealing structure-function relationships in the design of nanomaterials for electrochemical systems. The following topics will be discussed: 1) well-defined materials obtained by varying their surface structure, composition profile and electronic properties [2]; 2) atomic/molecular insight into electrified solid-liquid interfaces; 3) identification of the active and the most vulnerable surface sites under reaction conditions; 4) insight into chemical nature between the surface atoms, reactants, and molecular species in the electrolyte; 5) engineering of advanced nanomaterials with desired size, shape and composition profile [3,4]; 6) ex-situ and in-situ characterization of tailored nanostructured electrochemical interfaces.
References:
[1] Stamenkovic et al. Science 315 (2007) 493.
[2] Stamenkovic et al. Nature Mat. 6 (2007) 241.
[3] van der Vliet et al. Nature Mat. 11 (2012) 1051.
[4] Chen et al. Science 343 (2014) 1339.
Potential-Dependent Structure of [BMIM][FSA]/Au Interface Studied By Surface Enhanced Infrared Absorption Spectroscopy
Authors: Motobayashi Kenta , Uchida Ken-ichi , Osawa Masatoshi 
Published: February 2020

Room temperature ionic liquids (RTILs) are promising electrolyte materials for Li ion batteries and other electrochemical devices due to high ionic conductivity and wide electrochemical windows. It has been reported that the cathodic decomposition potential of the FSA-based RTIL is much lower than that of TFSA-based RTIL when Li salt is added, despite the similar chemical structures of FSA and TFSA anions. A mechanism for stabilization of the FSA-based RTIL on the electrode involving an interfacial structure of the RTIL has been proposed.1 The interfacial structure itself, however, has not been well elucidate yet. Surface-enhanced infrared absorption spectroscopy (SEIRAS) that can selectively probe solid/liquid interfaces is suited for direct observation of the structure of RTIL/metal electrode interface.2 In the present work, we investigated the potential-dependent structure of [BMIM][FSA] with and without Li ion on an Au electrode by using SEIRAS.
For pure [BMIM][FSA], Potential-dependent SEIRA spectra indicated that at negative potentials, BMIM cations exist in the first ionic layer on the electrode and reorients depending on the potential, as previously reported for [BMIM][TFSA].2 For [BMIM][FSA] with 10 % Li salt, SEIRAS spectra suggested that BMIM cations moved further away from the electrode at negative potentials where Li UPD did not occur although electrode is negatively charged. FSA anions also did not approach to the surface. A possible interpretation of such behavior is that decomposition products of [BMIM][FSA] or Li+ ion on the electrode inhibit cations from approaching to the electrode at negative potentials, which can be the origin of the stabilization of FSA-base RTIL. Details will be shown in the presentation.
Reference:
1M. Yamagata et al.,

Electrochim. Acta 110, 181 (2013).

2

K. Motobayashi et al.,

J. Phys. Chem. Lett. 4, 3110 (2013).
(Invited) Si Photoelectrodes with Patterned Catalysts for Efficient and Stable Photoelectrochemical Solar Chemical Production
Authors: Oh Jihun 
Published: February 2020

Solar fuel production using sun, CO2, and water at a semiconductor/water interface attracts intense interest for converting solar energy into storable and distributable chemicals. While numerous semiconductors have been investigated, a tandem cell comprised of semiconductors with two different bandgaps is considered one of the most promising candidates for realization of for unassisted efficient and stable solar chemical production. Si has a bandgap of 1.12 eV and can be used as an ideal bottom cell in a tandem configuration.
Here, I’ll present our recent works on Si photoelectrodes with patterned co-catalysts for efficient and stable photoelectrochemical (PEC) solar chemical producing cells. In the first part of the presentation, I’ll talk about PEC properties of Si photoanode for oxygen evolution reaction with enhanced stability. Our Si photoanode is covered with chemically stable and electrically passivating SiO2 layer to prevent corrosion of Si in water. Since SiO2 is insulating, we locally pattern the oxide to expose Si surface and deposit Ni co-catalysts on the exposed Si. By controlling surface coverage of Ni co-catalysts, we achieve 27 mA/cm2 of oxygen evolving current density at 1.23 V (vs. RHE) for more than 24 hours. I'll present PEC device modeling of our Si photoelectrode structures. In the second part of talk, I’ll present Si photocathodes with nanoporous Au mesh for solar CO2 reduction reaction. Our Si photocathode with the nanoporous Au mesh shows CO2 reduction selectivity more than 90% at more positive potential than CO2/CO redox potential. In the presentation, PEC performance of our Si electrode will be presented in detail.
Active Sites of Plasmon-Induced Charge Separation
Authors: Nishi Hiroyasu , Saito Koichiro , Tatsuma Tetsu 
Published: February 2020

Plasmon-induced charge separation (PICS) occurs at the interface between plasmonic nanoparticles (e.g. gold, silver, and copper nanoparticles) and a semiconductor such as titanium oxide or zinc oxide.1,2 Plasmon-induced charge separation involves carrier transfer from the plasmonic nanoparticle to the semiconductor. It can be applied to photovoltaics and photocatalysis under visible and near infrared light, localized plasmon sensors for chemical sensing and biosensing, photochromic materials, and photoactuators. We have studied the active sites of plasmon-induced charge separation taking advantage of electrochemical reactions caused by the charge separation. For instance, we monitored dissolution of metal nanoparticles3,4 or metal nanostructures5 and redeposition of small metal nanoparticles resulting from recombination of released metal ions and electrons injected into semiconductor. We found that the active sites are localized at around the sites where optical near field is localized. In addition, we prepared porous nanoparticles on the basis of the metal dissolution caused by plasmon-induced charge separation.
1. Y. Tian and T. Tatsuma, J. Am. Chem. Soc., 127, 7632 (2005).
2. T. Tatsuma, Bull. Chem. Soc. Jpn., 86, 1 (2013).
3. E. Kazuma, N. Sakai, and T. Tatsuma, Chem. Commun., 47, 5777 (2011).
4. I. Tanabe and T. Tatsuma, Nano Lett., 12, 5418 (2012).
5. L. Wu, H. Nishi, and T. Tatsuma, APL Mater., 3, 104406 (2015).