bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signal Switch and Signal Amplification for Electrochemical Biosensing
Authors: Ju Huangxian 
Published: February 2020

Recently, the investigation on electrochemical biosensing has made great progress. The developed biosensors have extensively been used in different fields, particularly, the sensitive and accurate detection of DNA, protein and metal ions. The designs of specific signal switch and signal amplification strategies are becoming the main topic of electrochemical biosensing research. This presentation will introduce new signal switches and signal amplification strategies developed in last two years. For example, we prepared two electrochemical catalytic probes to design two molecular switches for electrochemical DNA sensing by coupling with porphyrin-encapsulated metal-organic frameworks. Several new signal amplification strategies based on nanotechnology and molecular biology have been presented for DNA detection and immunoassay. By the recognition of nucleic acids to metal ions, some signal switches and label-free methods have been developed for specific and sensitive detection of heavy metal ions. Some new electrochemiluminescent emitters have been synthesized and used for design of new ECL biosensing mechanisms. A wavelength-resolved ratiometric photoelectrochemical technique has also been developed for sensing applications. These works led to a series of amplified methods for sensitive detection of DNA, microRNA and protein.

References:
1. L. Cui, J. Wu, H.X. Ju, Biosens. Bioelectron. 79, 861-865 (2016)

2. J. Zhu, X.H. Huo, X.Q. Liu, H.X. Ju,ACS Applied Mater. Interf. 8, 341-349 (2016)
3. P.H. Lin, J.P, Lei, L. Jia, H.X. Ju, Chem. Commun. 52, 1226-1229 (2016)
4. Y.Q. Feng, C.H. Dai, J.P. Lei, H.X. Ju, Y.X. Cheng, Anal. Chem. 88, 845-850 (2016)
5. Q. Hao, J.P. Lei, X.N. Shan, Y. Zang, Q.H. Yang, H.X. Ju, Chem. Sci. 7, 774-780 (2016)
6. Y. Huang, J.P. Lei, Y. Cheng, H.X. Ju, Biosens. Bioelectron. 77, 733-739 (2016)
7. Y. Zang, J.P. Lei, Q. Hao, H.X. Ju, Biosens. Bioelectron. 77, 557-564 (2016)
8. L. Cui, J. Wu, H.X. Ju, Anal. Chem. 87, 10635-10641 (2015)
9. L. Cui, J. Wu, M.Q. Li, H.X. Ju, Elctrochem. Commun. 59, 77-80 (2015)
10. L. Cui, J. Wu, H.X. Ju, Chem Eur. J. 21, 11525-11530 (2015)
11. Y.Q. Feng, Q.B. Wang, J.P. Lei, H.X. Ju, Biosens. Bioelectron. 73, 7-12 (2015)
12. P.H. Ling, J.P. Lei, H.X. Ju, Biosens. Bioelectron. 71, 373–379 (2015)
13. Y. Zang, J.P. Lei, P.H. Ling, H.X. Ju,Anal. Chem. 87, 5430–5436 (2015)
14. P.P. Ling, J.P. Lei, L. Zhang, H.X. Ju, Anal. Chem. 87, 3957–3963 (2015)
15. P.H. Ling, Q. Hao, J.P. Lei, H.X. Ju, J. Mater. Chem. B 3, 1335–1341 (2015)
16. K. Ren, J. Wu, F. Yan, Y. Zhang, H.X. Ju, Biosens. Bioelectron. 66, 345–349 (2015)
17. L. Cui, J. Wu, H.X. Ju, Biosens. Bioelectron. 63, 276-286 (2015)
Monitoring Ammonium Ions in Oral Microbiome
Authors: Ummadi Jyothir Ganesh , Bahro Chris Bernhard , Koley Dipankar 
Published: February 2020

Ion selective electrodes are used to measure real time ionic concentrations in biological systems including bacterial biofilms. The beneficial bacteria in the oral microbiome plays an important role by producing ammonium ions in the presence of L-arginine and urea. The production of ammonium ions creates an alkaline environment which neutralizes the acidity caused by the pathogenic bacteria. The neutralization of acidity is important to prevent dental caries. Measuring the ammonium ion concentration gives important details about the activity of the beneficial bacteria in different environments.
We developed a solid contact ammonium ion selective electrode to study the release of ammonium ions from the beneficial bacteria. The sensor had a nernstian response and a dynamic range of 10 µM to 100 µM and good selectivity against common interferants like Na+, K+, H+. The sensor was used to test the release of ammonium ions in the vicinity of pathological bacteria to study the neutralization of acidic environment. This study will help in determination of ammonium ion concentration required to maintain homeostasis in the oral microbiome. The characterization of ammonium ion sensor and the measurement of ammonium ions in the oral microbiome will be presented at the conference.

Figure 1
Ru-Core@Pt-Shell Nanosheet Anode Catalyst: High Activity and Durability for Hydrogen Oxidation Reaction in the Presence of CO
Authors: Takimoto Daisuke , Ohnishi Tomohiro , Nutariya Jeerapat , Shen Zhongrong , Ayato Yusuke , Mochizuki Dai , Demortiere Arnaud , Boulineau Adrien , Sugimoto Wataru 
Published: February 2020

PtRu alloy nanoparticles are presently used as the anode catalyst for residential polymer electrolyte fuel cells due to its high carbon monoxide (CO) tolerance. Unfortunately, PtRu alloy is not as stable as pure Pt, and the gradual dissolution of Ru from the catalyst surface leads to catalyst degradation. In an earlier study, we have shown that the addition of metal or metal oxide nanosheets as co-catalysts to carbon supported PtRu/C catalysts can enhance the CO tolerance and durability 1,2. Here we describe the synthesis of Ru-core@Pt-shell nanosheets via surface limited redox replacement 3. The CO tolerance and durability of Ru-core@Pt-shell nanosheets towards the hydrogen oxidation reaction activity in the presence of CO is presented.
Metallic Ru nanosheets supported on carbon composite was prepared via thermal reduction 2. Pt shell was successively formed on metallic Ru nanosheets via galvanic displacement reaction between Cu and Pt2+ by repeating the displacement reaction twice. The electrochemically active PtRu surface area of Ru-core@Pt-shell nanosheets with 1.5 monolayer Pt-shell (Ru@Pt-1.5ML(ns)/C) was 95 m2 (g-PtRu)-1, and the hydrogen oxidation reaction activity in pure H2 of Ru@Pt-1.5ML(ns)/C was 2.4 times higher than benchmark commercial PtRu/C. The H2 oxidation activity in the presence of 300 ppm CO for core-shell nanosheets was 1.5 times higher than that of PtRu/C. In addition, the activity of Ru@Pt-1.5ML(ns)/C after durability test (0.05 (3sec)-0.40 V (3 sec) for 1000 cycles) was 2.0 and 2.3 times higher than that of PtRu/C and Pt/C, respectively. The high activity in pure H2 could be attributed to the large surface area of core-shell structure, and the enhanced CO tolerance could be attributed to the electronic effect from the Ru nanosheet core. Ru nanosheet core was completely covered with Pt-shell, thus, the degradation of activity due to dissolution of Ru was suppressed.
This research was supported in part by the “Polymer Electrolyte Fuel Cell Program” from the New Energy and Industrial Technology Development Organization (NEDO) of Japan.
1) D. Takimoto, T. Ohnishi, and W. Sugimoto, ECS Electrochem. Lett., 4, F35 (2015).
2) D. Takimoto, T. Ohnishi, Y. Ayato, D. Mochizuki, and W. Sugimoto, J. Electrochem. Soc., 163, F367 (2016).
3) J. Nutariya, M. Fayette, N. Dimitrov, and N. Vasiljevic, Electrochim. Acta, 112, 813 (2013).

Figure 1
Synthetic Variations of Hollow Graphene Nanoshells for Li-Ion Battery Anode
Authors: McKenzie Kevin R. , Banek Nathan A , Hays Kevin Alan , Wagner Michael J 
Published: February 2020

The pyrolysis of cellulose produces bio-fuels, a net carbon neutral energy source, and bio-char that can be used as a soil enhancer. The economic feasibility of the production of bio-fuel from fast growing plants that can grow rapidly on minimally viable land, such as switch grass, would be greatly enhanced by producing higher added value products from the bio-char. Pyrolyzing bio-char in the presence of metal halide catalysts with a CO2laser for a few seconds results in the production of hollow graphene nanoshells (HGNS), a carbon negative material, which can be used in place of graphite active materials in Li-ion battery anodes with remarkably higher charge rate capability and low temperature performance in relatively inexpensive electrolytes.
Graphite is the most widely used anode active material in commercial Li-ion batteries. With a standard reduction potential of -2.9 V vs SHE and theoretical gravimetric capacity of 372 mAh/g (at LiC6) it provides 2 to 3 times the energy density compared to aqueous battery chemistries. The challenge remains to charge graphite anodes at the very high rates required for applications such as electric vehicles while maintaining its capacity over thousands of cycles. Shortening the Li-ion diffusion distance in graphite crystallites allows one to increase the charging rate, however, small graphite particles have poor cycle life.
We utilize hollow graphene nanoshells that have orders of magnitude shorter diffusion distances than standard graphite as an anode active material. These HGNS are made up of concentric multilayer graphene shells ~50 nm in diameter that intercalate Li+ in manner analogous to graphite but with remarkably higher charge rate capability (up to 22% charge in 7.2 s) and low temperature performance in relatively inexpensive electrolytes such as PC. Unfortunately, the storage capacity for HGNS is lower than graphite (~220 mAh/g vs. ~330 mAh/g practical), which motivated us to investigate synthetic variation to improve HGNS. Here we will present the results of our studies, finding that simple, inexpensive modifications to the synthetic procedures can result in HGNS with 40% greater reversible capacity (320 mAh/g) with no capacity loss after 100 cycles and a Coulombic efficiency of 99.9%. This new form of carbon is a very promising anode active material that could enable Li-ion batteries with dramatically faster charging rates, longer cycle lives and much better low temperature performance than standard graphite anodes. Furthermore, adoption of this carbon negative material in place of synthetic graphite could have a significant impact on global climate change, both directly by CO2 sequestration and indirectly by improving the economic viability of bio-fuels.

Figure 1
Lithium - Redox Battery Using a Solvate Ionic Liquid
Authors: Sugiyama Masaru , Tachikawa Naoki , Yoshii Kazuki , Katayama Yasushi 
Published: February 2020

Redox flow batteries have been expected as the large scale storage battery. Redox flow batteries utilize the oxidation and reduction of two soluble redox couples for charging and discharging without the solid phase reaction. Therefore, the cycle lives of the redox flow batteries are expected to be much longer than those of rechargeable lithium batteries using insertion-type active materials. Currently, vanadium redox flow batteries have been put into practical use to stabilize the supply of renewable energy. Vanadium redox flow batteries have low energy density compared to other batteries. Since aqueous solution is used for the electrolyte, the electrochemical window of the water limits the cell voltage. Although there has been various studies using an organic electrolyte in order to enlarge the cell voltage, the flammability and volatility of the organic solvents can be disadvantageous from the point of view of safety. 1)

Recently, aprotic ionic liquids have attracted attention as nonaqueous electrolytes. Especially, aprotic ionic liquids containing bis(trifluoromethylsulfonyl)amide (TFSA-) have been studied extensively in the electrochemical field because they show favorable features such as incombustibility, involatility and wide electrochemical potential window. We have already reported the redox reactions of various metal complexes in the ionic liquids and their applicability to redox flow batteries. 2) However, there are a few reports regarding the redox battery using the ionic liquids probably due to lack of the suitable ion exchange membrane that can move the career ion in the ionic liquids.
In the present study, a new redox battery, namely “lithium-redox battery”, was proposed using a redox reaction of an iron complex for a cathode reaction, dissolution and deposition of lithium for an anode reaction, and LiTFSA – tetraglyme (G4) solvate ionic liquid for an electrolyte. In addition, lithium ion conductive solid electrolyte (LICGCTM) was used as the diaphragm, which prevents penetration of the redox species and enables transfer of lithium ions. Tris(2,2'-bipyridine)iron(II) complex ([Fe(bpy)2]2+) was found to be soluble and stable in the solvate ionic liquid. The redox reaction between [Fe(bpy)3]2+ and [Fe(bpy)3]3+ was confirmed to be reversible by cyclic voltammetry. The formal potential of [Fe(bpy)3]3+/2+ was 4.1 V vs. Li|Li(I). Reversible charge-discharge cycling of the lithium redox battery having an average cell voltage of 3.9 V was possible for 30 cycles with a coulombic efficiency of more than 95%.
References
1) Y. Matsuda, K. Tanaka, M. Okada, Y. Takasu, and M. Morita, J. Appl. Electrochem., 18, 909 (1988).
2) Y. Katayama, M. Yoshihara, and T. Miura, J. Electrochem. Soc., 162, H501 (2015).
Electropolymerization of Thiophene in a Bis(fluorosulfonyl)Amide Based Phosphonium Ionic Liquid
Authors: Nishihata Keiichi , Tsunashima Katsuhiko , Ono Yasushi , Matsumiya Masahiko 
Published: February 2020

Room-temperature ionic liquids (RTILs) have been regarded as potential electrolytic media for electropolymerization processes.1 Many kinds of RTILs have been investigated for the electropolymerizations. For example, we have reported that a bis(fluorosulfonyl)amide (FSA) anion based imidazolium ionic liquid promoted the electropolymerization reaction of pyrrole and the anion doping into the polymerized film, improving the conductivity of the film.2 We also have applied the phosphonium based RTILs to the electropolymerization of pyrrole, investigating the influence of the phosphonium RTILs on the polymerized film properties.3 However, electrosynthesis of polythiophene in phosphonium RTILs has not been examined. In this work, we report the electropolymerization of thiophene in triethylpentylphosphonium FSA (P2225-FSA) and the effect of the phosphonium RTIL on the polythiophene film properties.
P2225-FSA was prepared according to the procedure we have previously reported,4 and dried under high vacuum at 80°C for 6 h before use. The electropolymerization of thiophene in P2225-FSA was carried out by cyclic voltammetry (CV) method using a three-electrode cell equipped with a working electrode of platinum or transparent glass electrode and an IL-based Ag/Ag+ reference electrode.
Fig. 1 showed the cyclic voltammograms for the electropolymerization of thiophene in P2225-FSA. It was found that an irreversible oxidation peak was observed and maintained even when the cycle was repeated, forming the polythiophene film on the electrode surface. It is noted that the peak current at 2.2 V vs Ag/Ag+ was enhanced by cycling, which seems likely to be attributed to the efficient anion doping into the polymerized film grown on the working electrode surface. Fig. 2 depicted a SEM image of the polythiophene film grown in P2225-FSA. A uniform surface of the film grown in P2225-FSA was observed when compared to that in an organic solvent based electrolyte, which is closely similar to the result previously found in the electropolymerization of pyrrole. The electrochemical activity and thermal stability of the polythiophene film obtained will be discussed.
References
1. K. Sekiguchi, et al, J. Electroanal. Chem.
1, 557 (2003).
2. K. Tsunashima, et al, ECS Electrochem. Lett., 3, G1 (2014).
3. K. Honma, et al, Abstracts of the Electrochemical Society of Japan
82nd Spring Meeting, PS27 (2015).
4. K. Tsunashima, et al, Electrochem. Commun., 13, 178 (2011).

Figure 1
2D Metal Carbide(Ti3C2Tx) Electrochemical Capacitors in Ionic Liquids
Authors: Alhabeb Mohamed , Van Aken Katherine L , Anasori Babak , Gogotsi Yury 
Published: February 2020

Two dimesional (2D) metal carbides, known as MXenes,have attracted interest in energy storage applications due to their unique properties[1-3]. Pseudocapacitors are types of electrochemical capacitors in which energy is stored via surface redox reactions mechanism.
Here, we studied free standing films of titanium carbide MXene (Ti3C2) as pseudocapacitor electrodes in inoinc liquids (ILs) electrolytes. In comparison to aqueous electrolytes, the use of ILs enables us to increase the operating voltage window of MXene based electrodes and leads to high energy density. This study opens new door for MXene based electrodes in applications that requires high energy density.

References:

1. Naguib, M., et al., Two
‐Dimensional Nanocrystals Produced by Exfoliation of Ti3AlC2. Advanced Materials, 2011. 23(37): p. 4248-4253.
2. Lukatskaya, M.R., et al., Cation intercalation and high volumetric capacitance of two-dimensional titanium carbide. Science, 2013. 341(6153): p. 1502-5.
3. Ghidiu, M., et al., Conductive two-dimensional titanium carbide/clay/'with high volumetric capacitance. Nature, 2014. 516(7529): p. 78-81.
Nanoparticle Dynamics in Room Temperature Ionic Liquids
Authors: Tanner Eden E L , Batchelor-McAuley Christopher , Compton Richard G 
Published: February 2020

Nanoparticle dynamics in Room Temperature Ionic Liquids (RTILs) is an underexplored field, despite high interest in RTILs in nanoparticle synthesis, the modification of electrodes and as catalysts. The solvent environment of a RTIL provides a high ionic strength medium in which to understand nanoparticle dynamics and the role of the capping agent in electron transfer to the nanoparticle.
Oxidation of silver nanoparticles capped with poly(ethylene) glycol in 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim BF4) is reported for the first time (J. Phys. Chem. C, 2015,
119 (32), 18808-18815). The oxidation of the nanoparticles shows a time dependency, suggesting that the nanoparticles assemble at the electrode surface and time allows the polymer coating to undergo an unwrapping process before the silver core is accessible for electron transfer with the electrode (‘polymer-gated’).
The addition of chloride, commonly present as an impurity in RTILs, allows 'nano-impacts', where by the nanoparticle travels to the electrode surface via Brownian motion before undergoing electron transfer as it makes contact with the electrode, to be observed novelly in a RTIL. (J. Phys. Chem. C, 2016, 120 (3), pp 1959–1965). The presence of the chloride allows the nanoparticles to undergo oxidation to silver chloride, which does not require rearrangement of the polymer.
Finally, the importance of the capping agent, and its control over the mechanism of oxidation, has been established (Chem. Eur. J, 2016, doi:10.1002/chem.201505117). Examining nanoparticles capped with 2000, 6000, and 10,000 MW poly(ethylene) glycol reveals a shift in the mechanism of silver oxidation (from nano-impact to polymer gated).
Electrochemical Detection of Low-Concentration Ammonia Gas on Miniaturised Electrodes in Room Temperature Ionic Liquids
Authors: Hussain Ghulam , Silvester Debbie S. 
Published: February 2020

The detection of ammonia (NH3) gas at low concentrations is of great importance due to its use in a wide range of industries e.g. the oil and gas industry, fertilizer industry, refrigeration industry1 and due to its high toxicity. Concentrations as low as 500 ppm can be lethal, and the current (USA) Occupational Health and Safety Permissible Exposure Limit (OSHA PEL) is 25 ppm in the gas phase. There are commercially available electrochemical gas sensors to monitor ammonia, mostly based on amperometric gas sensors (AGSs). However one problem with AGSs is that their solvent/electrolyte combinations are typically water/sulphuric acid, and can dry-up quickly, thus making the lifetime of these sensors very limited. Room Temperature Ionic Liquids (RTILs) have been attracting a great attention as replacement electrolytes in AGSs2 due to their unique physical properties such as wide electrochemical windows, high intrinsic conductivity, low volatility and negligible vapor pressure, high chemical and thermal stability and their ability to dissolve a wide range of compounds. Importantly, they do not evaporate when exposed to a high gas flow, and can function in hot and dry environments. In our work, we are investigating commercially available thin-film metal electrode surfaces as new sensing surfaces, consisting of three electrodes that are incorporated onto a small area on an inert substrate. Their small size means that only a few microliters RTIL solvent needed, and the small amount of inert metal required (e.g. platinum) minimizes the overall cost of the sensor. Four different techniques will be employed for ammonia oxidation: linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV), and potential-step chronoamperometry (PSC) over the concentration range of 10-100 ppm NH3. The results on commercially available Pt thin-film electrodes, screen-printed electrodes, and microarray thin-film electrodes will be compared to “ideal” Pt microdisk electrodes. Calibration curves (current vs. concentration) for all voltammetric techniques on all four surfaces will be presented, showing excellent linearity with increased concentrations of NH3. The limits of detection found on all four surfaces for all four techniques are in the range of ca. 2-5 ppm, much lower than minimum exposure limit (25 ppm) for NH3. These results are highly encouraging and suggest that RTILs and low-cost miniaturised electrodes can be combined in sensor devices to detect ammonia gas at low ppm concentrations.
References:
(1) Stetter, J. R.; Li, J. Chemical Reviews
2008, 108, 352-366.
(2) Buzzeo, M. C.; Hardacre, C.; Compton, R. G. Analytical Chemistry
2004, 76, 4583-4588.
Mesoporous Materials
Authors: Dam Duc Tai , Lee Jong-Min 
Published: February 2020

Over the last decade, due to increasing environmental pollution and depletion of fossil fuels, considerable effort has been devoted to the development of clean and sustainable sources of energy. On top of that, latest technological advancements in market of hybrid electric vehicles and electronic devices lead to a need of alternative energy storage/conversion systems with higher powers and energy densities. As a result, electrochemical energy systems are grasping more attention as alternative energy sources.
In our research, we combined methods to obtain mesoporous materials which can be used as electrode material of supercapacitor with very high specific capacitance. We will discuss the influence of electrodeposition parameters such as deposition potentials, deposition temperatures and deposition time on the electrochemical capacitor behavior.

Acknowledgements Funding support for the research from Singapore Maritime Institute Maritime Sustainability (MSA) R&D Programme is gratefully acknowledged.