bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Converting Petroleum Coke into Hydrogen
Authors: Tao Greg Gege
Published: February 2020

Hydrogen has been long recognized as a potential chemical fuel to meet worldwide energy needs while reducing (and eventually eliminating) CO2 and other GHG emissions. It is widely used by petroleum refineries in upgrading processes, necessary to facilitate the hydrotreating/catalytic hydrocracking of heavy hydrocarbon molecules, and the reduction of sulfur content. Hydrogen, as a secondary energy carrier, doesn’t exist in an elemental form in the environment to an appreciable extent, but can be produced by reacting a variety of widely available primary energy carriers with water or by using renewable energy sources, either directly or indirectly. At an industrial scale, three major technologies are presently used to produce hydrogen, depending on the primary energy sources or available feedstock: coal gasification, natural gas steam reforming, and water electrolysis.

Petroleum coke (or petcoke), similar to coal, is a byproduct of refinery processes. The U.S. refineries produce more than 125,000 short tons petcoke per day (st/d). With a low heating value (LHV) of 6.024 MMBtu/barrel (equivalent to 8.826 MWhr/st), petcoke produced in the U.S. potentially is worth 17,689 MW electricity assuming 40% efficiency. However, due to larger activation energies, higher sulfur content and less volatile materials than coal, petcoke is not a desirable feedstock for the conventional coal-burnt power plant and more than 62% of petcoke was exported annually.

Instead of purchasing hydrogen over the fence, a refinery potentially can build on-site hydrogen production infrastructure directly utilizing its available resource (petcoke). Materials & Systems Research Inc. currently has been developing an advanced hydrogen production process built-upon the solid-oxide electrochemical technology with reduced energy consumption and low costs for CO2 separation & sequestration. In this talk, a scalable hydrogen production process will be discussed. Proof-of-concept demonstration of hydrogen production at a 200W stack level will also be presented.
Predictive Control of Catalyst Selectivity in the Electroreduction of Carbon Dioxide
Authors: Billy Joshua , Co Anne
Published: February 2020

The direct electrocatalytic reduction of carbon dioxide to fuel-type chemicals remains a promising utilization pathway to mitigate rising carbon dioxide concentrations in the atmosphere. Copper metal is the most widely studied catalyst used in the reaction due to its unique ability to produce hydrocarbon species. While a lot of focus has been improving the catalysts, the experimental parameters that affect the reaction have not been fully understood.

A variety of factors have been shown to affect the activity and selectivity of the CO2 electroreduction reaction. Pre-electrolyzing the electrolyte is a common practice after Hori et al.

1
determined that trace impurities in the salts used to make the electrolyte solutions can deposit on the electrode surface and inhibit the reaction. High purity metal electrodes (ex. Cu 99.999+ %) are used for a similar reason. The identity of the electrolyte also has an effect, leading to different product distributions even by simply using a salt with a different alkali metal cation2. Electrolyte concentration has also been shown to alter the product selectivity3. Hori et al. concluded that the cationic species and electrolyte concentration affect the local pH at the electrode surface, which plays a major role in regulating the reaction.

Other researchers have also demonstrated the importance of local pH and its effect on the reaction. Gattrell et al.

4
calculated the surface concentrations of several important species in the electroreduction of CO2 in KHCO3 solutions, showing that local concentrations are drastically different from the bulk. Factors such as current density and boundary layer thickness play a role.

To optimize our electrochemical set-up, we investigated how the CO2 bubbling rate and the solution flow rate within an electrochemical flow cell affected the reaction. We found that the selectivity between CH4 and C2H4 can be predictively controlled by varying the bubbling rate and solution flow rate, and that the two are inversely related. A combination of mass transport processes and local pH affects can be used to explain our observations. This work highlights the importance of controlling parameters in the electroreduction of CO2 and demonstrates predictive control of hydrocarbon selectivity.

 

1. Y. Hori, H. Konishi, T. Futamura, A. Murata, O. Koga, H. Sakurai and K. Oguma, Electrochimica Acta, 2005, 50, 5354-5369.

2. A. Murata and Y. Hori, Bulletin of the Chemical Society of Japan, 1991, 64, 123-127.

3. Y. Hori, R. Takahashi, Y. Yoshinami and A. Murata, Journal of Physical Chemistry B, 1997, 101, 7075-7081.

4. N. Gupta, M. Gattrell and B. MacDougall, Journal of Applied Electrochemistry, 2006, 36, 161-172.
Influence of Anion-Exchange Ionomers on Electrocatalysts for Carbon Dioxide Reduction
Authors: Manthiram Karthish , Fenwick Aidan Q. , Edwards Julian P. , Grubbs Robert H.
Published: February 2020

Electrochemical fixation of carbon dioxide may provide a sustainable path for generating both hydrocarbon fuels and commodity chemicals. By powering such electrochemical processes using sources of clean, direct electricity, it is possible to re-envision the carbon cycle and reduce the carbon footprint associated with producing these products.

Practical architectures for electrochemical carbon dioxide reduction devices are likely to involve membrane-electrode assemblies (MEAs) in order to minimize the ionic diffusion length scale and maximize energy efficiency. MEAs consist of sandwich structures in which cathodic and anodic gas diffusion layers (GDLs) are on either side of a membrane. Electrocatalysis occurs in the gas diffusion layers (GDLs), which must facilitate transport of reactants, products, ions, and electrons. As a result, GDLs contain nanoparticulate catalysts, carbon black for electronic conductivity, ionomers for ionic conductivity, and binders for structural stability. Although GDLs require contacting of catalytic nanoparticles with ionomers in order to deliver and remove ions from the catalyst surface, the effect of the ionomers on the underlying catalyst is poorly understood for carbon dioxide reduction.

This presentation will focus on the influence of anion-exchange ionomers on the activity and selectivity of transition-metal electrocatalysts for carbon dioxide reduction. Using electrochemical studies and vibrational spectroscopy, the interaction of the anion-exchange ionomers with the catalyst surface has been elucidated. Based on the results, insights for the design of ideal anion-exchange ionomers for incorporation into GDLs for electrochemical carbon dioxide reduction will be presented.
Tuning the Selectivity of CO2 Electrochemical Reduction Toward Hydrocarbon with Ligand Modified Metal Electrocatalyst
Authors: Fang Yuxin , Cheng Xun , Xu Ye , Flake John
Published: February 2020

Reduction of CO2 has become an attractive process to form fuels from renewable energy sources. Multiple approaches (electrochemical, photochemical, homogeneous catalysis, etc.) have been made to optimize this artificial photosynthesis. The electrochemical approach has the benefit from using low-cost electrical energy (wind or solar) and producing renewable hydrocarbon fuels. Various metals and their alloys (Au, Ag, Cu, Pd and Pt etc.) have been studied exhaustively on their catalytic ability in CO2 electrochemical reduction.(1) With the calculation basis in the scaling relationship by Nørskov et al., nanoscale cathode catalysts are continuously being explored results in achievement in highly selective production of CO, formate and methane, etc. (2-4) The challenge to develop the optimal catalyst lies in the selectivity toward the desired product in which liquid form product is favored due to transportation consideration.

Inspired by the nature’s enzyme catalyzing photosynthesis that yields outstanding selectivity, we consider the ligand’s effect on the selectivity. Gold has been known to catalyze the CO2 reduction to produce CO with trace amount of formate. In present work, we demonstrate the ability in tuning the selectivity of this reaction by control the surface pKa with different organic thiol self-assembled monolayer. As shown in figure 1, the selectivity of CO and formate have been alternated at the present of 4-mercaptanethylpyridium on gold foil thus the product was switched from gas phase toward liquid phase. Surface chemistry has been shown to hold promising role in designing catalyst selectively.

REFERENCE

1. Y. Hori, in Modern Aspects of Electrochemistry, C. Vayenas, R. White and M. Gamboa-Aldeco Editors, p. 89, Springer New York (2008).

2. C. Shi, H. A. Hansen, A. C. Lausche and J. K. Norskov, Physical Chemistry Chemical Physics, 16, 4720 (2014).

3. D. R. Kauffman, D. Alfonso, C. Matranga, H. Qian and R. Jin, Journal of the American Chemical Society, 134, 10237 (2012).

4. K. Manthiram, B. J. Beberwyck and A. P. Alivisatos, Journal of the American Chemical Society, 136, 13319 (2014).

Figure 1
An Investigation into the Electrocatalytic Activity of Nitrogen Doped Metalated Carbons
Authors: Donne Scott W , Kwong Laurence
Published: February 2020

Energy is a globally important commodity, used from powering our homes and appliances to helping produce goods that improve society’s quality of life. The majority of the world’s energy requirements are currently provided by fossil fuel sources such as coal, oil, and natural gas. The extended use of these fuels in the past has contributed to significant climate change which is adversely affecting our environment and is unsustainable in the long term. Clean and renewable sources such as solar power and wind power have emerged as technologies that can produce energy with zero emissions. One of the most significant issues preventing the widespread adoption of these renewable technologies is their intermittent output which is affected by variations in the wind load or incident radiation. This prevents these technologies from providing reliable base load power, especially during peak periods at night time. A solution to this is the use of hydrogen for energy storage which is produced using renewable energy.

One of the most promising technologies for the efficient, large scale production of hydrogen from water is the hybrid sulphur cycle. This cycle utilises cheap and abundant sulphur dioxide as a chemical depolariser, reducing the potential required to produce hydrogen from water compared to conventional electrolysis. In this process, sulphur dioxide is oxidised at the anode of an electrolyser, producing sulphuric acid and hydrogen ions which are subsequently reduced at the cathode to produce hydrogen gas. The sulphuric acid is then thermally decomposed to produce water, oxygen, and regenerate the sulphur dioxide for recycling. One of the inhibitors to this technology is the requirement of expensive noble metal catalysts such as palladium and platinum for the oxidation reaction, and so one of the challenges of the scientific community is to identify suitable low cost alternatives.

Much work has demonstrated the improvement in the catalytic activity of carbon electrodes through the process of nitrogen doping. This work will examine the effect of nitrogen doping on the catalytic activity of nitrogen doped metalated carbons in the hope to identify suitably active alternatives to the noble metals or at the very least, reduce the quantities required.
CO2 Electro-Reduction on Bio-Inspired Iron Sulfide Under Mild Conditions
Authors: Roldan Alberto , de Leeuw Nora
Published: February 2020

In recent years, carbon dioxide capture and utilisation is gaining attention driven not only by environmental factors but also by the potential to use it as chemical feedstock. One plausible utilisation route is its conversion to form small organic molecules, yet CO2 is thermodynamically very stable and its reduction is energy intensive. Nevertheless, the CO2 conversion takes place under mild conditions in chemoautotrophic bacteria catalysed by enzymes.1 These enzymes often contain Fe4S4 clusters, which have been shown to act as electron-transfer sites 2, 3 but they can also be catalytically active centres for molecule transformations.4 An iron thio-spinel mineral is structurally similar to this cluster,5 fact that brings us to suggest it as a novel heterogeneous catalyst. We present a theoretical investigation using the iron sulfide greigite mineral (Fe3S4) as a catalyst to transform CO2 into small organic molecules, such as formic acid, methanol and acetic acid. In agreement with the experiments, the adsorbed species and the products formed depends on the solution pH. The reduction consists of a sequential hydrogenation steps that we have studied by either the common Langmuir-Hinshelwood or the Eley-Rideal mechanisms. We have identified more than 170 intermediates describing the different reaction pathways where the most favourable ones lead to formate and carboxyl as key intermediates in the reduction process. The selectivity is controlled by different sites on the surface sites yielding mainly HCOOH and CH3OH. However, some surface species interact among them to generate molecules with higher carbon content.

References

[1] C. Huber and G. Wachtershauser, Science, 276 (1997) 245

[2] Y. Nicolet, P. Amara, J. M. Mouesca and J. C. Fontecilla-Camps, Proc. Natl. Acad. Sci. U. S. A. 106 (2009) 14867

[3] T. Hayashi and A. Stuchebrukhov, Abstr. Pap. Am. Chem. Soc.243 (2012)

[4] H. Seino and M. Hidai, Chemical Science 2 (2011) 847.

[5] W. Martin and M. J. Russell, Phil. Trans. Royal Society 358 (2003) 59

Figure 1
Direct Charge and Discharge Using the Glycolic Acid/Oxalic Acid Redox Couple for the Carbon-Neutral Energy Circulation
Authors: Yamauchi Miho , Hata Shinichi , Kitano Syo , Sadakiyo Masaaki , Takeguchi Tatsuya
Published: February 2020

The major impact of increasing CO2 concentration on climate change has been recognised. Thus, efficient utilisation of renewable electricity is of increasing significant importance and development of various manner of its operation is required for our energetic and environmental sustainability. Recently, electric power storage in high-energy chemicals, called “energy carriers”, has received much attention for the efficient storage and on-demand supply of renewable electricity. Here, we demonstrate direct power charge using an alcohol/carboxylic acid redox couple. Highly transportable glycolic acid, an alcoholic compound, was successfully produced by electroreduction of oxalic acid, a dicarboxylic acid, on ubiquitous TiO2 catalysts with high efficiency and selectivity (70-95% Faradaic efficiency and >98% selectivity) under mild conditions in the potential region of -0.5 to -0.7 V vs. the RHE at 50 ºC. The most desirable characteristic of this electroreduction is the suppression of hydrogen evolution even in acidic aqueous media (Faradaic efficiency of 70–95%, pH 2.1). The detailed observation of TiO2 catalysts using scanning TEM and eels techniques provided a mechanistic insight into the highly selective catalysis. Recently, we coud demonstrate glycolic acid synthesis using an electrochemical cell consisting of the TiO2catalyst and a polymer electrolyte, i.e., a polymer electrolyte alcohol synthesis cell.

　Furthermore, we succeeded in electric power generation via the selective electrooxidation of glycolic acid to oxalic acid without CO2emission—specifically, carbon-neutral power generation. These results are the first experimental proof of concept for a carbon-neutral energy circulation system based on charging/discharging electric power using an alcohol/carboxylic acid redox couple[1, 2] as shown in Fig. 1.

Reference

[1] R. Watanabe, M. Yamauchi, M. Sadakiyo, R. Abe, T. Takeguchi, “CO2-free electric power circulation via direct charge and discharge using the glycolic acid/oxalic acid redox couple",
Energy Environ. Sci.
, 8, 1456-1462 (2015).

[2] T. Matsumoto, M. Sadakiyo, M.L.Ooi, S.Kitano, T.Yamamoto, S.Matsumura, K. Kato, T. Takeguchi, and M. Yamauchi, “CO2-Free Power Generation on an Iron Group Nanoalloy Catalyst via Selective Oxidation of Ethylene Glycol to Oxalic Acid in Alkaline Media” ,
Sci. Rep.
, 4,5620(2014).

Figure 1
The Role of Doped Ceria Buffer Layer on Phase Evolution in Pr2NiO4+d cathode and Approached to Suppress Their Reaction in Solid Oxide Fuel Cells
Authors: Dogdibegovic Emir , Alabri Nawf Saif , Wright Christopher J. , Zhou Xiao-Dong
Published: February 2020

During operation Pr2NiO4+δ cathode undergoes partial phase transitions which results in evolution of PrOx and higher order layered structure (Pr3Ni2O7). Simultaneously, the elemental diffusion occurs where praseodymium migrates towards cathode/buffer interface and reacts with doped ceria deep within its bulk. It is speculated that the presence of ceria may promote the diffusion of Pr into the buffer layer due to a large solubility of Pr in ceria. Recently, we observed that the elemental substitution with Nd on the A-site in Pr2NiO4+δ can slow the diffusion process. With increase in Nd content the formation of PrOx and higher order Pr3Ni2O7 phase is suppressed. In this presentation, we will discuss (1) the role of buffer chemistry on the diffusion or Pr and (2) whether or not the absence of Pr in buffer layer further promotes the phase evolution in Pr2NiO4. Thermal annealing tests were performed at various temperatures and compared to electrochemical measurements in full cells. X-ray diffraction and scanning electron microscopy analyses were used to study the long term phase evolution and reaction with buffer layer.
X-Ray Diffraction and in-Situ Synchrotron Studies on Phase Evolution in Pr2NiO4: Understanding the Local Structure Changes
Authors: Dogdibegovic Emir , Wright Christopher J. , Zhou Xiao-Dong
Published: February 2020

Solid oxide fuel cells produce electricity from the electrochemical oxidation of a wide variety of fuels. Recently, a layered-oxide cathode material, Pr2NiO4, has captured the field’s interest. Pr2NiO4 is performance stable and shows higher power densities than commonly used cathodes. However, it partially decomposes under operating conditions, which has little impact on the cell performance. Preliminary thermal stability results show that after only 50h at 790 °C the parent phase undergoes substantial decomposition, which is evident by evolution of PrOx and other layered phases. However, industrial applications require minimal phase changes over long term operation, due to possible structural collapse, requiring stabilization of Pr2NiO4. The active phase(s) are unknown in operating cells, as is the reason why the phase change has little effect on the performance. In this work in-situ x-ray total scattering atomic pair distribution function (PDF), and x-ray powder diffraction (XRD) analyses were used in an attempt to track phase evolution in Pr2NiO4 during thermal annealing and electrochemical operation. The study focuses on the role of PrOx and other layered byproducts on cell stability and performance. PDF and XRD were used to solve the changing Pr2NiO4 atomic structure via Monte Carlo simulations. This work presents an attempt to obtain fundamental knowledge of the local structure changes occurring in Pr2NiO4 and its byproducts, which in turn could provide a better understanding on the phase stabilizing mechanism.

The authors would like to thank the Department of Energy for their support of this project under contract #DE-FE0023475. The use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In Situ Optical Studies of CO2 and Co-Electrolysis
Authors: Qadri Syed Noorullah , Kirtley John D. , Steinhurst Daniel A , Balow Robert Benjamin , Pehrsson Pehr E. , Owrutsky Jeffrey C
Published: February 2020

The ability to understand the underlying mechanisms for electrolysis of CO2 and co-electrolysis of CO2 and steam has been hindered due to a lack of experimental methods that can probe intermediate species and materials directly during operation. Although there have been studies on using Ni-YSZ and ceria based cathodes for electrode materials in high temperature solid oxide electrolysis cells (SOECs), these have mainly utilized post-mortem and in situ electrochemical analyses. Here, we demonstrate an in situ duplex technique that combines near infrared thermal imaging (NIRTI) and Fourier-transform infrared emission spectroscopy (FTIRES) to monitor processes for electrolysis of CO2 and co-electrolysis on operating SOECs. The results are correlated with traditional electrochemical measurements to identify any polarization dependence on species during the course of reactions under a range of conditions.

CO2 and co-electrolysis conditions are investigated on anode- and electrolyte-supported cells between 700 and 900 °C. NIRTI results indicate cooling on the anode surface during endothermic processes and heating during high loads due to joule heating. FTIRES indicates the first observation of a carbonate intermediate formed on a cathode during operation at normal SOEC working pressure and temperature. Diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) is used to confirm band assignments seen in situ for electrode materials. Ex situ mass spectrometry and exhaust gas FTIR absorption measurements are combined with in situ results to further characterize and quantify carbon monoxide and syn-gas production. These studies serve as benchmark data for better understanding the processes during CO2 electrolysis in real working conditions.
Carbide Supported Phosphides Are Superior Electrocatalysts for Hydrogen Generation Than Nanocrystalline Phosphides
Authors: Regmi Yagya N , Roy Asa Logan , Goenaga Gabriel A. , Zawodzinski Thomas A. , Labbe Nicole , Chmely Stephen
Published: February 2020

Phosphides such as hexagonal nickel phosphide (Ni2P) and carbides such as hexagonal Fe2N type molybdenum carbide (Mo2C) have been extensively explored as efficient and stable hydrogen evolution reaction (HER) catalysts in both acid and base electrolytes. To a lesser extent, they have also been investigated as oxygen evolution reaction (OER) catalysts in alkaline medium in recent years. Molybdenum carbide has been shown to exhibit superior enhancement in the electrochemical activity compared to carbon materials as support for noble metal catalysts such as platinum. It has also been shown that carbon support deposited phosphides show enhanced HER and OER activities compared to nanocrystalline phosphide powders. Thus, a carbide supported nickel phosphide should show relatively enhanced electrocatalytic activities than carbon supported material as well as unsupported crystalline powders. While the two families of materials have been investigated individually, to our knowledge, there is not a report of a composite material of phosphide and carbide. Since both phosphide and carbides can form hexagonal crystal structure there is likelihood that some phosphides can be deposited on molybdenum carbide surfaces. The electrocatalytic activities of phosphides and carbides depend on the optimal adsorption and desorption energies of hydrogen and hydrogen ion species for the reaction to proceed efficiently. Formation of composite electrocatalysts is postulated to give rise to superior catalyst sites. This presentation will investigate the structural and catalytic activities of transition metal phosphide deposited on carbothermic reduction derived molybdenum carbide. Additionally, intermetallic interactions and electrochemical stabilities of the composite catalysts will be discussed.
Fouling Behavior of Multivalent Cations to Cation Exchange Membranes in Reverse Electrodialysis
Authors: Kim Da-Eun , Oh Yoontaek , Choi Jang-Uk , Song Chan-Ho , Chae Soryong , Kim Chan-Soo , Jeong Nam-Jo , Kang Moon-Sung , Park Jin-Soo
Published: February 2020

Reverse electrodialysis (RED) represents an energy conversion technology from the salinity difference of concentrated salt solutions (e.g., sea water) and diluted salt solutions (e.g., river water). The RED stack is comprised of an alternating arrangement of cation- and anion-exchange membranes between two electrodes that selectively transfer anions and cations. However, the sea water used for the RED may contain the divalent cations (i.e., Ca2+ and Mg2+). Thus, electrostatic characteristics of divalent cations may lead to membrane surface fouling. The membrane fouling cause increase electrical resistance and the increase of maintenance cost, and a significant decrease in operating performance. In this study, the influence of membrane fouling in RED by divalent cations such as Ca2+ and Mg2+ was investigated experimentally, and equilibrium tests, open circuit voltage, stack resistance, and power density were measured at different operation conditions. Commercially available cation exchange membranes were used. As a result, the divalent ions behaved a reversible foulant to cation exchange membranes caused an increase in resistance. Calcium ion exchanged cation exchange membranes showed higher resistance than magnesium ion exchanged ones. It is also concluded that the number of hydration attached to cations greatly influenced resistance.

Acknowledgements

This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, and Republic of Korea (No. 20143030071240).
Effects of Natural Organic Matter on Desalination of Coal Mine Wastewater Using a Capacitive Deionization System
Authors: Chae Soryong , Park Jin-Soo , Seo Yong-Seog
Published: February 2020

Secure access to sufficient and clean water is imperative to sustainable mining production. Water pollution from mining activities raised public concern on the negative impacts of coal mining on water quality and quantity. Therefore, coal mine industry increased water recycling to protect their access to water resources while expanding their operations. However, water recycling without control of salinity can generate elevated salt concentrations in feed water streams resulting in deterioration of product quality. In this study, we developed a coagulation/sedimentation (C/S) – microfiltration (MF) - capacitive deionisation (CDI) system and evaluate its performance as an alternative desalination technique for recycling of coal mine wastewater. Desalination experiments were performed by using synthetic coal mine wastewater (CMW) and a bench-scale CDI system equipped with activated carbon (AC) electrodes. The effects of ion-exchange polymer coated on AC electrodes, turbidity and natural organic matter (NOM) on desalination performance of the hybrid system were investigated. As a result, pre-treatment of turbidity by the coagulation and MF membrane filtration increased desalination performance of the CDI. However, natural organic matter (NOM) affected adversely on salt removal efficiency of the CDI.
(Invited) Printable Paper-Based Wearable Diaper-Type and Adhesive Bandage-Type Biofuel Cells for Urine Sugar and Sweat Lactate Monitoring
Authors: Shitanda Isao
Published: February 2020

Printable Electrochemistry has attracted attention for the development field of a disposable biosensor and biofuel cell. A printable paper-based biofuel cell (PBFC) is useful for energy harvesting power sources in the Internet of Things (IoT) field [1-3]. In addition, PBFC is suitable for an application as a self-powered wearable sensor. In the present study, I introduce two paper-based wearable biofuel cells fabricated by screen-printing technique (Fig. 1). One is used as a self-powered diaper sensor (right side in Fig. 1). The biofuel cell can generate electric power from glucose in urine. The maximum output power increase along with increase of glucose concentration. Thus, we can monitor the glucose concentration by measuring the maximum output power. The paper-based biofuel cell exhibited a maximum power density of 0.7 mW in 100 mM glucose solution. Our group also developed an adhesive bandage-type biofuel cell, which get a power from lactate in sweat (left side in Fig. 1). In the present study, we discuss the characteristics of the wearable biofuel cells in detail.

Acknowledgement

This work was supported by JST-ASTEP Grant Number AS272S004a.

References

[1] I. Shitanda, S. Kato, Y. Hoshi, M. Itagaki, S. Tsujimura, Chem. Commun. 49 (2013) 11110.

[2] Claudia W. Narváez Villarrubia et al., Electrochem. Commun, 45 (2014) 44.

[3] Carolin Lau et al., Int. J. Hydrogen. Energy, 42 (2015) 14661.

Figure 1
Bioelectrochemical Catalysis Reversal Reaction in Purification and Resources of Mineral Processing Flue Gas Via BECR
Authors: Wang Li , Sun Yang , Hu Ning , Wang Jie
Published: February 2020

The Bio-electrochemical catalysis reactor (BECR) is employed to purify SOx, NOx, carbon dioxide and other pollutants from mineral processing flue gases in mineral processing. They are converted into sulphur and nitrogen and high added-value biofuels via biological agent of seperating air/pollutants and bioelectrocatalysis reversal process (BECRP). Biofuel producing bacteria and BECR reactors are coupled to a system, and the BECRP is utilized and realized to purify mineral processing flue gas and convert carbon dioxide biofuel in the reactors. The metabolic products, mineral processing flue gas components of influx and exhaust and other processing parameters are analysed by using online Micro-GC, HPLC-MS, and etc. The influences of microbial metabolic pathway of the BECRP and low voltage loading on the bacteria and the electrode reaction mechanism in the electrode process are investigated. The multi-variable bioelectrochemical transition matrix and optimal parameters are established to improve the flue gas purification efficiency and the conversion rate of carbon dioxide.
Electrochemistry Based Platform for the Highly Sensitive Detection of Human Parathyroid Hormone Using Au Electrode with MoS2/Graphene Matrix
Authors: Lee Min-Ho , Kim Hye Youn , Lee Kook-Nyung , Seo Youngtai
Published: February 2020

A self-assembled novel nanocomposite composed of MoS2-Graphene(MoS2-Gr) composites were electrostatically formed on top of gold (Au) electrode and their biochemical amplification responses were reported. The properties of the MoS2-Gr were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FT-IR).  Cyclic voltammetry was performed in the presence of Parathyroid Hormone (PTH) and its linearity was obtained by measuring the anodic current signals coming from interactions between MoS2-Gr-Ab and different concentrations of PTH with the aid of substrate and enzyme conjugated secondary antibodies. With this complex and Au as working electrode, we have developed a portable biosensing platform which shows good sensitivity in detecting PTH as low as 10 pg/mL and high reproducibility
Elasticity Measurement of High-Metastatic Breast Cancer Cells That Highly Express Intermediate Filament Protein Nestin
Authors: Yamagishi Ayana , Takano Yuta , Mishima Mari , Imaizumi Miku , Okada Tomoko , Nakamura Chikashi
Published: February 2020

Nestin is an intermediate filament protein that is used for a neural stem cell marker. Since its high expression was reported in several high-metastatic cancer cells, nestin is considered to be involved in metastasis of cancer cells1. However, relationship between nestin and metastatic mechanism of cancer cells is unknown. Cancer cells are generally softer than benign cells2. Because intermediate filaments contribute to cell mechanical property by binding with other cytoskeletal proteins, nestin expression could affect elastic modulus of cancer cell. Previously, we have obtained a highly metastatic murine breast cancer cell line, SC2 which expressed three-fold nestin of parent strain. In this study, we established nestin-knockout SC2 cell by CRISPR/Cas9-mediated genome editing to evaluate an effect of nestin disruption on the cell.

Intermediate filaments are composed by three domains and rod domain in the N-terminus is necessary to form bundles. In order to disrupt nestin gene, sgRNA was designed to target the rod domain of mouse nestin. Plasmid expressing the sgRNA and Cas9 was transfected into the SC2 cells by lipofection. After transfection, the cells were cultured in RPMI 1640 medium including G418 (500 μg/mL) for 10 days. Obtained clones were confirmed by immunostaining and three clones were found to be disrupted nestin. Analysis of genome sequence revealed that frameshift mutation was occurred by deletion of nucleotides in nestin gene of the obtained clones. These results indicated that nestin knockout succeeded by CRISPR/Cas9-mediated genome editing.

To examine in vivo metastatic activity of nestin knockout cells, the SC2 and knockout cells were intravenously injected into mice. Survival time of mice injected with nestin-knockout cell was significantly prolonged, suggesting that nestin knockout reduced metastatic ability of the SC2 cells. We measured elastic modulus of cell body by using of atomic force microscopy (AFM) and cylindrical-shaped AFM probe with 2.2 μm in diameter. Force curve obtained when the probe was contacted with cell surface was fitted by Herz model and young’s modulus was calculated. Since the young’s modulus of the nestin-knockout cell was significantly higher than that of the SC2, nestin knockout caused increase in mechanical property. In the metastasis process, cancer cells invade surrounding tissue. Thus, expression of nestin reduces the elastic modulus in the cell body and leads high metastatic activity.

(1) Kleeberger, W. et al. Cancer research 67, 9199-9206, 2007.

(2) Cross, E. S. et sl. Nature nanotechnology 2, 780-783, 2007.
(Invited) Diamond Electrodes for Sensitive Electrochemical Detection
Authors: Kondo T.
Published: February 2020

Boron-doped diamond (BDD) electrodes are known to have excellent electrochemical properties, such as wide potential window and low background current, as well as extreme physical/chemical stability. Based on these properties, the BDD electrodes are expected to be used for sensitive electrochemical detection in various research fields including bioelectrochemistry. Usually, BDD electrodes are prepared by deposition of a polycrystalline BDD thin film on a conductive silicon wafer substrate, and thus obtained as an inflexible macro-electrode. In order to expand application fields of BDD electrodes for sensitive electrochemical detection, we have developed screen-printed BDD electrodes and BDD microring electrodes.

1. Screen-printed BDD electrodes

Screen-printed BDD electrodes were developed as a low-cost, light-weight, flexible, disposable and sensitive electrochemical electrode. An ink containing BDD powder (BDDP, particle size < 1 μm) and polyester (PES) resin binder was prepared and was subjected to screen printing to obtain a polyimide film-based screen-printed BDD electrode. In comparison with conventional carbon-printed electrode, the BDDP-printed electrode was found to show low background current, leading to large signal-to-background (S/B) ratio. Electrochemical properties of the BDDP-printed electrode was changed drastically by the PES/BDDP ratio of the ink. The BDDP-printed electrode showed planar electrode-type behavior at small PES/BDDP ratios. At a BDDP-printed electrode with large PES/BDDP ratios, however, microelectrode-type voltammetric behavior was observed due to the random microelectrode array effect. The S/B ratio for the voltammetric detection of ascorbic acid was found to be in the order BDDP-printed electrode (PES/BDDP = 1.0) > BDDP-printed electrode (PES/BDDP = 0.3) > conventional polycrystalline BDD electrode.

2. BDD microring electrodes

BDD microring electrodes were developed for electrochemical detection at a micrometer-scale local space. A quartz glass rod was pulled to prepare a quartz glass needle with a tip diameter of ca. 200 nm. BDD thin film was deposited on the needle tip to obtain BDD microelectrode. After deposition of an insulating layer on the electrode surface, the tip was cut by focused ion beam to obtain microring electrode. Diameter of the BDD microring electrode was ca. 5 μm. Oxygen reduction reaction current at a platinum microelectrode in the presence of bovine serum albumin (BSA) was found to be reduced by 58% from the current in the absence of BSA. In contrast, the current reduction was found to be 20% at the BDD microring electrode, showing good durability to electrode fouling by the presence of BSA.
Electroreduction of Nitrobenzene: Nominal Simulation of Voltammogram
Authors: Haque Inam ul
Published: February 2020

For the electrochemical reduction of nitrobenzene in aqueous cationic micellar solution of cetyltrimethylammonium bromide [CTAB] at platinum electrode using cyclic voltammetry, a reversible/quasi reversible charge transfer reaction pertaining to one electron couple of ArNO2/ArNO2.- was indicated (1). Digital simulation was used to evaluate electrochemical kinetic parameters for the mono-electron transfer step (1).

An ECE mechanism, Scheme-1 and Figures 1 and 2 and Table-1, is suggested for the previously reported voltammograms (2) featuring nitrobenzene reduction on a coated platinum electrode partially covered by a thin film of dioctadecyldimethylammonium chloride [DODAC].

Table-1:
Diffusion coefficients for nitrobenzene (2)

 Diffusion coefficient (cm2/s)

6.11×10-5

1.09×10-4

Bare Pt
DODAC covered Pt, this work

References

(1) Tariq, M.; Haque, I. U., Science International (Lahore), 2016, 28, 361

(2) Haque, I. U.; Tariq, M., Journal of the Chemical Society of Pakistan, 2011, 33, 529

Figure 1
Electrochemical Homo-Coupling Reaction of Brominated Phenols
Authors: Obata Rika , Yamamoto Takashi , Naba Keisuke , Ohba Shigeru , Einaga Yasuaki , Nishiyama Shigeru
Published: February 2020

Electrochemical homo-coupling reaction of brominated phenols was investigated. In the asymmetric synthesis, the structural motif of 2,2’-biphenyl provides chiral chelating ligand systems and therefore they are categorized as privileged chiral catalysts. Also, the 2,2’-biphenyl unit has been found as bioactive centers in several natural products. The 2,2’-biphenyl molecule with bromide functional group would be a useful synthetic tool to construct further C-C bond formation. However, synthetic methods to obtain brominated 2,2’-bipnenyls are less common, and direct coupling reaction of brominated phenols resulted with low to moderate yield. Recently we have found iodine mediated one step coupling reaction to construct brominated 2,2’-biphenyl from 4-brominated phenol. This reaction was applied to electrochemical reaction. The electrochemical reactions and results of the biological assay of the obtained compounds will be discussed.
Electrochemical Metal-Free Ring-Opening Metathesis Polymerization
Authors: Ashikari Yosuke , Pascual Laura M M , Ogawa Kelli A , Boydston Andrew J
Published: February 2020

Ring-opening metathesis polymerization (ROMP) is widely used for the synthesis of polymers, typically using a transition-metal-based initiator. Much effort based on improvement of catalyst design and polymerization techniques has led to breakthrough applications in diverse areas, including high-performance plastics, drug delivery, bioengineering, and organic photovoltaics. We reported an electrochemical polymerization technique using a vinyl ether as an initiator, which is directly oxidized to a radical cation at a carbon anode during bulk electrolysis. However, polymerization was only observed on the electrode surface, resulting in low yields. We hypothesized the low efficiency was due to the heterogeneous nature of the direct oxidation. Herein we report on the development of a method for the indirect electrochemical oxidation of the initiator via an electrochemical mediator to achieve metal-free-ROMP. Preliminary cyclic voltammetry analyses predicted the feasibility of electron transfer between the mediator and the initiator. In addition to these recent results, ongoing work will developing electrochemical ROMP methods via indirect oxidation of the initiator will be discussed.
Structural Manipulation of Carbon Nitride for Electrochemiluminescent Analysis
Authors: Zhang Yuanjian
Published: February 2020

Chemical structures of two-dimensional (2D) nanosheet can effectively control the properties thus guiding their applications. However, carbon nitride nanosheets with tunable chemical structures and sizes has been rarely explored so far, thus impeding the further boost of performances. Herein, we demonstrate that carbon nitride nanosheets with tunable chemical structures can be obtained by liquid-exfoliation of facile accessible bulk carbon nitride with different polymerization degree. In comparison with previous methods for preparation of 2D nanosheets, the proposed route was green, not requiring any additives, toxic solvents or preintercalation steps. On the other hand, detection of metal-ions as known is crucial for health due to both deficiency and overdose of them will cause the imbalance of homestasis and subsequenet severe diseases. Interestingly, the ECL of as-prepared carbon nitride nanosheers (CNNS) was significantly modulated, and exhibited unusual changes in quenching and enhancement upon adding different metal-ions. Such advantage was further applied to construct sensors for multiple metal-ions without any labeling and masking reagents. The detection limit estimated at a signal-to-noise of 3, of Cu2+, Ni2+, and Cd2+ were 250 nM, 1 nM and 20 nM, respectively, which was 2~340 times lower than the maximum level in drinking water permitted by WHO. Detailed mechanism studies further revealed that the strong ECL quenching effect was due to the inner filter effect/electron transfer process and the enhancement was due to the catalytic effect. It would open a vista to explore 2D carbon-rich materials for a wide range of applications such as sensing with enhanced performances based on new mechanism.

Reference

[1]Zhou, Z.; Wang, J.; Yu, J.; Shen, Y.; Li, Y.; Liu, A.; Liu, S.; Zhang, Y. J. Am. Chem. Soc.
2015, 137, 2179.

[2] Zhou, Z.; Shen, Y.; Li, Y.; Liu, A.; Liu, S.; Zhang, Y. ACS Nano
2015, 9, 12480.

[3]Shang, Q.; Zhou, Z.; Shen, Y.; Zhang, Y.; Li, Y.; Liu, S.; Zhang, Y. ACS Appl. Mater. Interfaces
2015, 7, 23672.
Enhanced Electrochemiluminescence on Indium Tin Oxide Modified with Dendrimer-Encapsulated Nanoparticles
Authors: Kim Joohoon
Published: February 2020

Here, we report enhanced electrochemiluminescence (ECL) on indium tin oxide (ITO) electrodes modified with amine-terminated dendrimers encapsulating catalytic nanoparticles, which can be applied for sensitive electrochemiluminescence(ECL)-based assay. Specifically, we prepared Pt and Au dendrimer-encapsulated nanoparticles (DENs) using amine-terminated polyamidoamine (PAMAM) dendrimers, and subsequently immobilized the DENs onto ITO surfaces via electrooxidative grafting of the terminal amines of dendrimers to the surfaces.[1] The resulting DEN-modified ITOs preserved good optical transparency of ITO and exhibited highly catalyzed electrochemical oxidation of Ru(bpy)3
2+ (bpy, 2,2’-bipyridine)/ tri-n-propylamine (TPrA), leading to significantly increased ECL emission.[2] Especially, the Pt DEN-modified ITO electrode provides negligible transmittance drop, i.e. only ~1.99% over the entire visible region, and exhibited not only much enhanced (i.e., ~213-fold increase compared to ECL obtained from bare ITO), but also stable ECL emission under consecutive potential scans from 0.00 to 1.10 V for 10 cycles, which allowed ~329 times more sensitive ECL-based analysis of nicotine using the Pt DEN-modified ITO compared with the use of bare ITO. However, we observed relatively poor stability of Au DENs on the ITO surfaces.[2] We found that the poor stability of Au DENs is closely related with the presence of chloride ions in electrolyte solutions.[3] In the absence of chloride ions, we demonstrated that the Au DEN-modified ITOs could be used as a versatile ECL based platform for sensitive electroanalysis of reactive oxygen species (ROS), such as hydrogen peroxide.

[1] S. B. Lee, Y. Ju, Y. Kim, C. M. Koo, and J. Kim, Chem
. Com
un
.
2013, 49, 8913.

[2] Y. Kim and J. Kim, Anal
. C
hem
.
2014, 86, 1654.

[3] Lee, S. B.; Kwon, J.; Kim, J. Electroanalysis
2015
, 27, 2180-2186.
(Invited) Structural Stability and Ionic Defects in Transition Metal-Oxides from Diffusion Quantum Monte Carlo
Authors: Santana Juan A. , Krogel Jaron T. , Kent Paul R. C. , Fernando Reboredo A.
Published: February 2020

Transition metal-oxides (TM) play a central role in many applications and in the fundamental research for advance materials. The standard computational methods to study these systems are based on Density Functional Theory (DFT) approximations. These approximations, however, are unreliable for a wide range of TM because they are based on model systems. A natural solution to overcome the intrinsic limitations of DFT approximations is to directly solve the many-body problem in TM. Today this is only practical by applying quantum Monte Carlo (QMC) methods. We will show that QMC methods, such as diffusion quantum Monte Carlo (DMC), are now practical to study multiple properties of TM. The application of DMC to study the structural, electronic and ionic defect properties of various TM, including ZnO, LaFeO3 and SrFeO3, will be presented.
Liquid Junction Potential Between Hydrophobic Ionic Liquid and Aqueous Electrolyte Solution
Authors: Yamamoto Masahiro , Kawai Kenji , Kakiuchi Takashi , Murakami Ryo
Published: February 2020

The liquid junction potential (LJP) across the two phases is very important for the basic science and real application of electrochemistry. In the case of the reference electrode the KCl salt-bridges are widely used, because the diffusion potential can be neglected in some cases by the almost same mobility of potassium ion and chloride ion in aqueous solution. However, if the difference of the concentration of solute between the two phases is great the LJP becomes several ten mV. And in the KCl salt-bridge KCl solution flow from reference electrode to the sample solution is essentially inevitable. To overcome these shortcomings of KCl salt bridge Kakiuchi et al. introduced the ionic liquid salt bridge (ILSB) concept and found that　LJP for ILSB is always constant and independent on the concentration of electrolyte in aqueous phase. The LJP for ILSB is distribution of cation an anion of IL to aqueous solution.[1]

　In the present study we have measured the electric conductivity of lithium bis(pentafluoroehtanesulfonyl)amide (LiC2C2N) and bis(pentafluoroethanesulfonyl)amide acid(HC2C2N) in aqueous solution. C2C2N anion is the ionic liquid component of ILSB and the cation is tributyl(2-methoxyethyl)phosphonium (TBMOEP). Form the conductivity measurements we have found that the molar conductivity at infinite dilution of C2C2N anion is 28.1 ± 0.7 S cm2 mol-1 and mobility is 2.91 × 10-4 cm2 V-1 s-1. Sakaida et al. reported the solubility of TBMOEP cation in aqueous solution is 2.64 x 10-4 cm2 V-1 s-1.[2] From these results we can estimate the diffusion potential across TBMOEPC2C2N | HCl solution using the Henderson equation. Even in the case of 0.5 mmol dm-3 the magnitude of the diffusion potential is 60　microvolt and the we can conclude that the diffusion potential is negligible in the TBMOEPC2C2N ILSB. We are now investigating the coupled Nernst-Plank and Poisson-Boltzmann equation to see the detail of the potential and the concentration profile.

 From the conductivity measurements we also found that HC2C2N is strong acid and C2C2N anion in aqueous phase is completely dissociated.

References

[1] T. Kakiuchi and T. Yoshimatsu,　Bull. Chem. Soc. Jpn. 79, 1017-1024 (2006).

[2] H. Sakaida, Y. Kitazumi, and T. Kakiuchi, Tantala, 83, 663-666 (2010).