bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Synthetic Catalysts for Water Oxidation Using Metal Complexes and Nanoparticles
Authors: Yagi Masayuki 
Published: February 2020

With solar cells, sunlight can be efficiently converted to electric power, however the electric power is instant. As soon as the Sun goes down, the electric power goes dim. On the other hand, conversion of sunlight into fuels provides a viable way of storing the sunlight for its permanent utilization. Green plants, algae, and cyanobacteria provide an efficient way of storing the sunlight in the form of sugars and starches using water and carbon dioxide (CO2) as feedstock materials by enzyme systems of high complexity in photosystems I and II in a process known as photosynthesis. The sunlight is utilized to get out electrons and protons from water via its oxidation at photosystem II with extremely high catalytic activity with turnover frequencies (TOFs) of 100-400 s-1 at overpotential (η) of only 160 mV. The electrons and protons are then siphoned off for the reduction of CO2 to sugars and starches at photosystem I.
Inspired from photosynthesis, researchers worldwide are trying to design an artificial photosynthetic device that could efficiently convert the sunlight to fuels (H2 or CO2 reduction products such as CH4, CH3OH, CO, HCOOH, …etc.) using a combination of inexpensive materials and water or water and CO2 as sustainable raw resources. Two artificial photosynthetic devices have been designed, photoelectrochemical (PEC, artificial-leaf) and photovoltaic (PV) driven electrolyzer. In both electrolyzers, water via its oxidation at the photoanode/anode is the source of protons and electrons required for the fuel production at the photocathode/cathode. Water oxidation, however, is a kinetically sluggish process because of the complexity of the reaction mechanism that involves the removal of four protons and four electrons from two water molecules to form O=O double bond It consequently requires a potential substantially higher than the thermodynamic value [E
0(H2O/O2) = 1.23 V, pH = 0], that is η, likely due to the generation of energetic intermediates in the multiple electron and proton coupling steps. The high η value complicates the design of efficient artificial photosynthetic device for fuel production. Consequently, it is crucial to develop highly efficient anodes for water oxidation to decrease η and thus realize efficient artificial photosynthetic device. Herein we report our recent progress on water oxidation catalyst of metal complexes and nanoparticles.
Nanocellulose Ionomer Membranes for Electrochemical Energy Conversion
Authors: Lyth Stephen Matthew 
Published: February 2020

Nanocellulose is a promising new ionomer membrane material for polymer electrolyte membrane fuel cells (PEFCs). It is the most abundant polymer in the world, making it much cheaper than conventional ionomer membranes such as Nafion or Aquivion. It I three times stronger and has three orders of magnitude lower hydrogen permeability than Nafion. We investigated the proton conductivity and prepared the world’s first operational PEFCs with nanocellulose membranes.
In order to improve the proton conductivity, we prepared sulfonated nanocellulose. To take advantage of the low hydrogen permeability and high strength, we developed very thin membranes. Spray-painting was used to fabricate “paper fuel cells” with 8 µm-thick sulfonated nanocellulose membranes. This resulted in high current density (almost 1 A cm-2), and a maximum power density of 156 mW cm-2 (H2/air, 80°C, 95% RH, 0.1 MPa).
The cost of these spray-painted sulfonated nanocellulose membranes was calculated to be ~50 $/m2, which is much lower than e.g. Nafion. This work paves the way for the mass production of affordable, recyclable, and even disposable fuel cells.

Acknowledgements: We acknowledge the support of Q-PIT; NEXT-FC, and WPI-I2CNER (sponsored by the WPI Initiative, MEXT), Japan. This research was partially supported by the Center of Innovation Program from Japan Science and Technology Agency, JST. The work was also partially supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B), Grant Number JP17K14087.

Figure 1
Nanofibrous Inorganic Semiconductors in Electrocatalytic CO2 Reduction
Authors: Aljabour Abdalaziz , Coskun Halime , Apaydin Dogukan Hazar , Stadler Philipp , Sariciftci Niyazi Serdar , Kus Mahmut 
Published: February 2020

The electrochemical carbon dioxide reduction reaction (CO2RR) is attractive in terms of resolving the ever-growing release of CO2 from anthropogenic cause. Thereby, electrochemical CO2RR combines high energy-transfer yields and the refinement to versatile products such as C1- chemicals, which represent the concurrent carbon feedstock.
Herein we explore the CO2 reducing property of nanofibrous chalcopyrite copper indium sulfide CuInS2 (CIS) and the pristine cobalt oxide (Co3O4), both p-type semiconducting materials, towards CO production mainly with remarkable faradaic efficiencies of 77% and 65%, respectively [1]. The focus in our studies are given to the utilization of the nanofiber electrodes as an appropriate electrocatalyst for CO production without using further expensive metal supplements, e.g. palladium, platinum, and potassium. Thus, the nanocrystalline shaping of nanofiber networks was achieved by the low-cost, versatile and time-saving electrospinning technique. In order to reduce the imperfection in the crystalline fiber, Polyacrylonitrile (PAN) was selected as template polymer [2]. The desired chemical structure of nanofibers was achieved through sintering process at 500 °C and 550 °C, respectively.
With reasonable product selectivity by CuInS2 and pristine Co3O4 nanofibers [3] and a stable operation at a constant electrolysis potential for many hours, we think that this work will stimulate more exploration into using nanofiber based materials in energy recovery and carbon capture and utilization technologies.
[1] Aljabour A.; Coskun H.; Apaydin D.H.; Ozel F.; Hassel A.W.; Stadler P.; Sariciftci N.S.; Kus M.; Applied Catalysis B: Environmental; 229; 2018; 163–170.
[2] Ozel F.; Kus, M.; Yar, A.; Arkan, E.; Yigit, M. Z; Aljabour, A.; Büyükcelebi, S.; Tozlu, C.; Ersoz M, Materials Letters. 2015, 140, 23–26.
[3] Aljabour A.; Apaydin D.H.; Halime Coskun, Ozel F.; Ersoz M.; Stadler P.; Sariciftci N.S.; Kus M.; ACS Appl. Mater. Interfaces 2016, 8, 31695−31701.
VUV-Assisted Photochemical Sol-Gel Processing of Metal Oxide Thin Films
Authors: Sun Lina , Kurosawa Yuu , Yoshida Tsukasa , Suzuri Yoshiyuki 
Published: February 2020

Metal oxides such as TiO2, ZnO, SnO2 are useful in many of energy devices because of their high chemical stability, n-type semiconductivity and photoelectrochemical properties. Various methods of solution processing of their thin films are known, such as chemical bath deposition, electrodeposition and sol-gel reactions. Typically, high temperatures need to be applied for crystallization to achieve good properties. The need of high temperature however limits the choice of substrates to heat-resistant materials. Also, crystallization often results in pinholes and cracks to damage the performance of devices.
We have developed an alternative sol-gel method to obtain ultra-smooth thin films of various metal oxides at room temperature, by employing photochemical decomposition of coated precursor by vacuum ultraviolet (VUV) light irradiation. The method is compatible with conductive plastic film substrates, so that multiple applications in thin film devices such as transparent conductive layer, light emitter, buffer layer in solar cells and thin-film encapsulation (TFE) as an example shown in Fig. 1 can be envisioned.

Figure 1
(Invited) Diffusion Map Analysis of Multi-Channel Time Series Data
Authors: Nakamura Takashi , Hagan Scott 
Published: February 2020

Sensor data often come in the form of multichannel time series, for example, ECG, EEG, and structural vibration monitoring to name a few. Conventionally, such multichannel time series data are analysed by using FFT for each channel, and/or by computing inter-channel correlations. Mathematically, however, these signals are better represented by dynamical systems, which are sets of differential equations.
The behaviour of a dynamical system may be visualised as a trajectory in the so-called phase space. For example, the state of a weight suspended by a spring can be fully described by the weight’s position x and its velocity v, hence its temporal behaviour creates a trajectory in its phase space (x, v). It works similarly for real systems that produce time series data. From a single channel of time series x(t) it is possible to reconstruct the phase space trajectory using lagged variables x(t), x(t-1), x(t-2),…., x(t-n). It is, however, very difficult to find and analyse the trajectory because the dimensionality of the phase space is very large in general.
In this presentation, we will show that a method called the diffusion map can extract the lower dimensional manifold in which the trajectory resides, and reveal the structure of the dynamics. Using some toy models we will demonstrate how our technique can be used to extract various useful information about the nature of the dynamics, including identification of anomalies, especially signs for imminent catastrophic changes such as phase transitions or structural collapse.
(Invited) Suspended Graphene-Based Sensor for Real-Time and Highly Sensitive Monitoring of VOCs
Authors: Kumar Rakesh , Dang Caroline , Hadi Faisal , Sexton James , Koehne Jessica E. , Boult Stephen , Dixon Neil , Migliorato Max 
Published: February 2020

Volatile organic compounds (VOCs) are emitted from solids or liquids with high vapor pressure and are often combustible and toxic, so on site real-time monitoring is vital. Currently photoionization detectors (PIDs) are used for VOC monitoring. PID devices are bulky and expensive to make and operated at high voltage to operate. As such there is a need for more portable and less expensive methods for detecting VOCs. We developed a novel gas sensor for (VOCs) detection. This technology utilizes suspended graphene membranes to provide real-time, ultrasensitive VOC detection. A freestanding graphene film suspended over an array of cavities or trench can offers increased surface area (twice over) and gives a direct method of sensing when VOCs adsorbed at the surface of graphene. Our sensor requires low voltages to operate, immediate response, high sensitivity and a larger theoretical range of detection than photoionization detectors sensors and it is a non-specific as PIDs.
In this work, we shall present a 3 mm X 3 mm square chip, fabricated using conventional photolithography, containing an array of two terminal devices. Each individual device consists of a monolayer graphene sheet suspended over multiple cavities and clamped by two metal contacts. Suspended graphene, as opposed to substrate-based graphene, significantly reduces the surface charge hindrances and allows for ultrasensitive detection of gas molecules. The fabricated graphene chip has been successfully tested for toluene vapors. Currently, testing is underway to functionalize graphene for selective detection of different gases.
References:

Yuan, Wenjing, and Gaoquan Shi. "Graphene-based gas sensors." Journal of Materials Chemistry A35 (2013): 10078-10091.

Kuila, Tapas, et al. "Recent advances in graphene-based biosensors." Biosensors and Bioelectronics12 (2011): 4637-4648.

Shao, Yuyan, et al. "Graphene based electrochemical sensors and biosensors: a review." Electroanalysis10 (2010): 1027-1036.

Jackowska, Krystyna, and Pawel Krysinski. "New trends in the electrochemical sensing of dopamine." Analytical and bioanalytical chemistry11 (2013): 3753-3771.
(Invited) Structural Analysis of Multifunctional Ionic Gels
Authors: Ahmed Kumkum , Naga Naofumi , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu 
Published: February 2020

Ionic liquied mediated gels commonly known as ion gels or ionic gels have received remarkable attention for their advanced application in electrochemical and electromechanical devices, such as actuators, lithium batteries, electric double-layer capacitors, dye-sensitized solar cells and fuel cells [1, 2]. Investigation of the internal structure of ionic gels have been previously reported by our research group to understand their network homogeneity in association with mechanical characterization[3]. In this work we focused to determine structural analysis of ionic gels combining multifunctional thiol monomers and IL 1-butyl-3-methylimidazolium bis(fluorosulfonyl)imide (BMImFSI). Therefore, we developed thiol monomer-based ionic gels via thiol-ene click reaction with theoretically homogeneous uniform network and investigated their mechanical properties using both conventional destructive method i.e. compression test and a unique nondestructive method using mesh size by scanning microscopic light scattering (SMILS) techniques [4]. The mesh size of the IGs was found to be highly dependent on the functionality of the monomer both in IL and conventional solvent media. Also long chain crosslinkers have been found to form dangling chain within the network hindering their homogeneous network formation. Thus our systems can offer to combine internal structures with the mechanical properties for characterization of soft materials in smart nondestructive ways.
References
[1] N. V. Plechkova, K. R. Seddon, Chem. Soc. Rev, 37, 123-150 (2008).
[2] T. Welton, " Chem. Rev
,
99, 2071-2084 (1999).
[3] Ahmed, K., Watanabe, Y., Higashihara, T. Arafune, H. Kamijo, T., Morinaga, T. Sato, T., Makino, M. Kawakami, M., Furukawa, H. Microsyst Technol 22, 17 (2016).
[3] H. Furukawa, K. Horie, R. Nozaki, M. Okada, Phys. Rev. E, 68, 031406 (2003)
Tunable Shape Memory Polymer with Adhesive Property at Body Temperature for Shape Conformable Wearable Sensor Skins
Authors: Shiblee MD Nahin Islam , Ahmed Kumkum , Nagahara Larry A. , Thundat Thomas , Furukawa Hidemitsu , Kawakami Masaru , Khosla Ajit 
Published: February 2020

Previously our group has developed poly(dimethyl acrylamide-co-stearyl acrylate (DMAAm-co-SA) based shape memory gels (SMG) [1] with high mechanical strength, very good transparency and biocompatibility having potential application in different sectors [2]. Most commonly used polymers in order to fabricate sensor skins is Polydimethylsiloxane (PDMS), but has a major drawback that it is not adhesive in nature [3, 4, 5].
In order to over come this problem, in this work we have incorporated adhesive properties by copolymerizing lauryl acrylate along with DMAAm and SA. The developed gels at body temperature had high transparency, good adhesive properties and wearability. Composition and temperature dependent adhesive properties of DMAAM-co-SA-co-LA has been investigated along with their mechanical, swelling and thermal properties and best suited adhesive SMG has been utilized to develop wearable skin sensor.
References:

Kabir, M.H., Ahmed, K. Furukawa, H., Microelectron. Eng. 150, 43–46 (2016).

Amano, Y; Hidema, R; Gong, J; Furukawa, H. Chem Lett.,41, 1029-1031 (2012)

Khosla, A., and B. L. Gray. "New technologies for large-scale micropatterning of functional nanocomposite polymers." In Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2012, vol. 8344, p. 83440W. International Society for Optics and Photonics, 2012. https://doi.org/10.1117/12.915178

Hesketh, Peter J., Durga Misra, Seiichi Takamatsu, Toshihiro Itoh, Ajit Khosla, Amir H. Saheb, Michelle Leon, and Mira Josowicz. "Conducting polymers and their applications." Electrochemical Society Interface 61 (2012): 3-4.

Khosla, A., and B. L. Gray. "Fabrication and properties of conductive micromoldable thermosetting polymer for electronic routing in highly flexible microfluidic systems." In Microfluidics, BioMEMS, and Medical Microsystems VIII, vol. 7593, p. 759314. International Society for Optics and Photonics, 2010. https://doi.org/10.1117/12.840911
(Invited) Si Materials for Li-ion Battery Negative Electrode Applications
Authors: Liu Gao 
Published: February 2020

Silicon is an attractive candidate for lithium-ion batteries negative electrode materials because it delivers 10 times greater theoretical (~4200 mAh/g) specific capacity than that of traditional graphite anode (~370 mAh/g). However, the widespread application of silicon materials has remained to be a significant challenge, originating from large volume changes during lithium insertion and extraction processes and excessive surface reaction with electrolyte. This large volume change causes cracking and pulverization of silicon, leading to loss of the electrical contact in the electrode. The Si volume change coupled with excessive electrolyte surface reaction, leads to drastic capacity fading.
To address the large volume change, new electrode fabrication approaches have been developed such as nano-Si materials assembly and new binder development. New functional binders with electronic conductivity, adhesive functional groups, and crosslinking functional groups are the recent research focuses.
To address the excessive surface reactions of Si with electrolyte, electrolyte additives of different chemistry has been developed and tested. Fluorocarbon additives such as FEC have demonstrated as an effective SEI formation additive for Si materials. Electrolyte additives for Si materials has been a very active area of research. Electrolyte additives with due functionalities have attract major interest lately.
Si particle coatings such carbon coating as an electric conductive medium and electrolyte insulating buffering layer have been widely used to encapsulate the silicon particles and prevent electrolyte reaction. There are many different carbon precursors for performing the carbon coating, which produce carbon coatings with different chemical and morphological carbon coatings. The Si materials with highly graphitized and dense coating is able to not only deliver higher gravimetric capacity and stable cycling compared to that of the Si with disordered carbon coating, but also alter the Si materials bulk transformation.
A comprehensive discussion of the Si materials coating, electrode design and electrolyte additives and its electrochemical performance will be presented.
K2[(VO)2(HPO4)2(C2O4)] and K
x
VOPO4
as 4 V-Class Positive Electrode Materials for K-Ion Batteries
Authors: Abdulrahman Shahul Hameed , Katogi Akihiro , Kubota Kei , Komaba Shinichi 
Published: February 2020

K-ion batteries (KIBs) potentially operate at high-voltage and high-current thanks to the lower standard electrode potential of K/K+ and the lower solvation energy than those of Li/Li+ in organic electrolytes and fast K-ion diffusion.[1] To realize practical applications, high energy density positive electrode materials are, however, indispensable. In this study, two vanadium based positive electrode materials with layered structure, namely, K2[(VO)2(HPO4)2(C2O4)] and and K
x
VOPO4 are synthesized and their electrode performances are examined in potassium cells. Highly reversible Li insertion/extraction oxalatophosphate material was reported with reversible capacities of >100 mAh g-1 and with a high voltage operation of ~3.8 V vs. Li/Li+. [2, 3] Hence, reversible K extraction/insertion and high voltage operation are expected in K cells.
K2[(VO)2(HPO4)2(C2O4)] was prepared by a simple precipitation method at room temperature. As shown in Fig. 1, K2[(VO)2(HPO4)2(C2O4)] delivers a reversible capacity of ~90 mAh g-1 in the K-half cell at 0.1 C in the voltage range of 2.5 - 4.5 V vs. K/K+ and excellent cycle stability is demonstrated. Furthermore, high rate capability with 76 mAh g-1 at 10 C is achieved by optimization of the electrolyte composition. Another vanadium-based layered positive electrode material, K
x
VOPO4 was also prepared by a precipitation method at room temperature. By optimization with carbon-coating and ball-milling, the material delivers a reversible capacity of 80 mAh g-1 at 3.7 V for over 200 cycles.
Fig.1: Voltage profiles and capacity retention plots of K2[(VO)2(HPO4)2(C2O4)] in a K-half cell.
References
[1] K. Kubota, S. Komaba, et al., Chem. Rec., 2018, 18, 459-479.
[2] A.S. Hameed et al., Sci. Rep., 2015, 5, 16270.
[3] A.S. Hameed et al., J. Mater. Chem. A, 2013, 1, 5721-5726.

Figure 1
Red Phosphorus-Based Materials As Anode for Na-Ion Batteries K-Ion Batteries
Authors: Yu Yan 
Published: February 2020

Recently, sodium ion batteries (NIBs) and potassium-ion battery (KIBs) have been attracted much attention since sodium and potassium resource is natural abundant, environmental friendly and showing similar chemical properties with lithium ion batteries. The red P anode for Na-ion and K-ion batteries has attracted great attention recently due to the high theoretical capacity, but the poor intrinsic electronic conductivity and large volume expansion restrains its widespread applications. The intrinsic low electronic conductivity of red P leads to the poor electronic kinetics, large polarization and further low active material utilization. In addition, the large volume expansion (~400%) during Na insertion/extraction in red P leads to pulverization of red P and loose contact between the red P and the current collector, resulting in the severe capacity fading.
Herein, we successfully encapsulate the red P into the carbon-based material (such as MOF-derived carbon, N-doped carbon, carbon-nanofibers) via the vaporization-condensation method.1, 2 Superior cycling stability (high capacity retention of about 93% at 2 A g-1 after 100 cycles) and excellent rate performance (502 mAh g-1 at 10 A g-1) could be obtained for the P/C electrode. The superior electrochemical performance could be ascribed to the successful incorporation of red P into the unique carbon matrix with large surface area and pore volume, interconnected porous structure, excellent electronic conductivity and superior structural stability.The porous carbon matrix with abundant micro/meso pores, large pore volume could effectively facilitate the infiltration of the electrolyte, and accommodate large volume expansion of red P during electrochemical process. The excellent conductivity of the carbon could ensure the essential electrical contact to the insulating red P, leading to excellent sodium storage performances. The rational design of the unique red P/ carbon structure could be served as a model for other anode material with poor intrinsic electronic conductivity and large volume expansion.
References:

Wu, Y.; Liu, Z.; Zhong, X.; Cheng, X.; Fan, Z.; Yu, Y., Amorphous Red Phosphorus Embedded in Sandwiched Porous Carbon Enabling Superior Sodium Storage Performances. Small
2018,
14, (12), 1703472.

Li, W.; Hu, S.; Luo, X.; Li, Z.; Sun, X.; Li, M.; Liu, F.; Yu, Y., Confined Amorphous Red Phosphorus in MOF-Derived N-Doped Microporous Carbon as a Superior Anode for Sodium-Ion Battery. Advanced Materials
2017,
29, (16), 1605820.