bluuebunny/crossref_metadata_2025_split huggingface dataset:
PEM Electrolyzer Characterization and Limitations When Using Carbon-Based Hardware and Material Sets
Authors: Young James L. , Ganci Fabrizio , Madachy Steven , Fischer Stefanie , Carmo Marcelo , Bender Guido 
Published: February 2020

In contradiction to the more established research field of proton exchange membrane fuel cells (PEMFCs), the research and development field for proton exchange membrane water electrolysis (PEMWE) is an upcoming and growing area. Over the past decades, a specific fuel cell research hardware configuration has been widely accepted for material development work that requires typical performance and durability tests on subscale cells. This hardware consists of thick endplates often made of aluminum, gold plated copper current collectors that are insulated with a sheet material from the endplate and graphite flow-fields that contain the flow channel structure. The latter may be machined in many designs ranging from single to multiple serpentine or parallel flow patterns.
In contrast to the fuel cell field, the electrolysis research field does not yet have established material sets. Operating conditions are harsher than in a fuel cell system, since the potentials required for the oxygen evolution reaction are significantly higher. In commercial water electrolysis systems this is compensated by typically using titanium material sets that are often protected against oxidation through coating processes. Such material choices make small scale research hardware and porous transport layers expensive and very difficult to source.
In this work, we show that the stability of traditional carbon-based fuel cell materials is sufficient for electrolyzer initial performance characterization procedures such as cell conditioning, a limited number of polarization curve measurements, and electrochemical impedance spectroscopy. We identify and quantify the onset of carbon degradation and define a strategy that allows the utilization of standard fuel cell hardware for specific PEMWE experiments. With knowledge that existing fuel cell materials can be applied in electrolyzer research by acknowledging the associated limitations, fuel cell research hardware and experience can be more readily transferred to the younger and rapidly growing electrolyzer research field.
Modulation of Excited State Dynamics in Semiconductor Electrodes with Electrical Bias
Authors: Samu Gergely F. , Balog Ádám , Scheidt Rebecca A. , Kamat Prashant V. , Janáky Csaba 
Published: February 2020

Semiconducting materials are essential building blocks of the majority of devices in the 21st century. The ability of semiconductors to generate charge carriers under band gap irradiation makes them suitable for a myriad of applications (e.g., solar cells, photocatalysts, photodetectors). In recent years the emergence of organic-inorganic lead halide perovskites revitalized these research fields. As a result, the efficiency of derived solar cells reached 22.3% in less than 10 years. To unravel the reasons behind their outstanding performance, it is vital to understand their optoelectronic properties. Spectroelectrochemical methods are suitable to determine fundamental optoelectronic properties (band edge and trap state energies) and electrochemical bias induced chemical changes in these materials. However, to probe charge carrier dynamics in these materials, it is essential to utilize ultrashort laser techniques, as these fast processes fall into the femto- or picosecond timescale.
In my presentation the effect of applied bias on the charge carrier dynamics of semiconductor electrodes will be discussed. Ultrafast spectroelectrochemical experiments were carried out on FTO/TiO2/CsPbBr3 and ITO/CuI systems by coupling ultrafast transient absorption spectroscopy with electrochemical techniques.1 These two systems have practical relevance in perovskite based solar cells, and their excited state behavior under operating conditions was scrutinized. It was found that the excitonic features of both CsPbBr3 and CuI are responsive to the applied external bias, within their electrochemical stability window. The accumulation of electrons on the TiO2/CsPbBr3 or ITO/CuI interface have a pronounced effect on charge carrier lifetimes in these studied materials. The change in charge carrier lifetimes in both CsPbBr3 and CuI was completely reversible showing the dependence of excited state dynamics on the externally controlled charge carrier density. This validates the in situ electrochemical transient absorption measurement as a useful tool to probe the charge carrier injection process in different semiconductor systems.

Scheidt, R. A., Samu, G. F., Janáky, C. & Kamat, P. V. Modulation of Charge Recombination in CsPbBr3 Perovskite Films with Electrochemical Bias. J. Am. Chem. Soc.
140, 86–89 (2018).
(Invited) Understanding Heterogeneous Functional Materials Via Scale-Bridging between Nano and Micro Transmission x-Ray Microscopy and Absorption Near Edge Structure
Authors: Zenyuk Iryna V. 
Published: February 2020

Heterogeneous functional materials for energy-conversion and –storage, such as fuel cells, electrolyzers and batteries are hierarchical, porous, electroactive materials that rely on multi-scale imaging techniques for accurate morphological characterization. These materials are building blocks for the catalyst layers, gas diffusion layers and electrodes in fuel cells, porous transport layers (PTLs) in electrolyzers and porous electrodes within batteries. Functional materials electrochemical functionality can be assessed with various in-situ and operando techniques that probe chemical state during operation, such as x-ray absorption near edge structure (XANES). Synchrotron bright x-ray sources allow for nano-scale imaging combined with XANES, which state-of-the-art lab-scale systems are still lacking. Furthermore, these bright sources allow ultra-fast imaging on sub-second and micro-second temporal resolution. Optimization of temporal, spatial and chemical dimensions is critical to answer the morphological and chemical questions of interest [1]. Transmission x-ray microscopy (TXM) and its three-dimensional analog x-ray computed tomography (CT) allows 30 nm resolution with nano-CT set-up and 1 um resolution with micro-CT beamlines. The nano-CT beamlines have precise energy resolution to enable a combination of 3D imaging and XANES. The generated imaging data sizes exceed terabytes of space and requires modeling frameworks to interpret the findings. We have developed a scale-bridging algorithm to incorporate nano-scale findings into micro-scale using direct numerical simulations and coupling algorithms via effective properties and boundary conditions.
In this work we will present several examples of operando data collected on fuel cells, electrolyzers and batteries using nano and micro x-ray CT and in some instances with XANES or with sub-second radiography. Full-field x-ray imaging beamline 18-ID at National Synchrotron Light Source II has achieved 3 minutes nano-CT scan, what enables full 3D XANES scan within reasonable time-frame. Some of the questions that we attempt to answer include activity and water management of NiCu/KB electrocatalyst used in alkaline fuel cells as anode; electrocatalyst activity and its interface with the PTL within operating electrolyzers, and Li metal dendrite growth in solid polymer electrolyte batteries during cycling. Scale-bridging framework is applied to fuel cell electrodes to understand oxygen transport and reaction-diffusion processes for these multi-scale catalyst layers.
References:

V. Zenyuk, “Bridging X-ray computed tomography and computational modeling for electrochemical energy-conversion and –storage”, Current Opinion in Electrochemistry, Volume 13, 2019, Pages 78-85.
High-Performance Oxygen Electrodes for Low Temperature Solid Oxide Cells
Authors: Chart Yvonne Antonia , Lu Matthew Yunching , Barnett Scott A 
Published: February 2020

Solid Oxide Cells (SOCs) present an efficient, environmentally friendly, and largely scalable method for converting fuel to electricity or generating fuels via electrolysis. It is generally believed that the commercial viability of SOCs can be improved by reducing the operating temperature, e.g., ≤ 650 °C. Since low temperature SOC performance is typically limited by the oxygen electrode, current research has focused on developing new oxygen electrode materials and architectures like Ba0.5Sr0.5Co0.8Fe0.2O3-δ, Sr0.5Sm0.5­CoO3-δ, and nanostructured electrodes with high surface areas in order to achieve low temperature performance. These materials, however, suffer from several degradation phenomena such as delamination, cation segregation, chemical reactivity, and coarsening. It was recently shown that PrOx infiltrated into a Gd-doped ceria scaffold provides very low polarization resistance values at low temperature.1 However, the long term stability is not known, nor is the mechanism for its good performance or its effect on other scaffold materials, either electronic conductors or mixed ionic and electronic conductors (MIECs).
Here we present results on PrOx infiltrated into Sr(Ti0.3Fe0.7-xCox)O3-δ (STFC) (0 < x < 0.15), STFC-GDC (Ce0.9Gd0.1O2-δ) composite, and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) scaffolds. Figure 1 illustrates the performance enhancing effects of PrOx infiltrated into LSCF and STFC MIEC scaffolds at 550 °C. For example, it decreases the initial polarization resistance of STFC from 0.57 to 0.22 Ω·cm2. The initial resistance decrease for LSCF+PrOx was even greater, from 2.05 to 0.58 Ω·cm2. The performance improvement is seen in the low frequency response, which is attributed to the catalytic surface processes related the addition of PrOx. Similar performance improvements are seen at 650 °C. Furthermore, the resistance values of STFC+PrOx and LSCF+PrOx are reasonably stable over ~ 1000 h life tests at 550 °C. The LSCF+PrOx result is particularly interesting since the LSCF electrode degrades considerably. The composite STFC-GDC+PrOx electrodes generally provide reduced polarization resistance compared to STFC-PrOx.

References

Nicollet, C., Flura, A., Vibhu, V., Rougier, A., Bassat, J.-M. & Grenier, J.-C. An innovative efficient oxygen electrode for SOFC: Pr6O11 infiltrated into Gd-doped ceria backbone. Int. J. Hydrogen Energy 2–8 (2016). doi:10.1016/j.ijhydene.2016.04.024

Figure Caption

Figure 1 - Evolution of Nyquist and Bode plots during a life test at 550 °C for ~ 1000 hours of (a) La0.6Sr0.4Co0.2Fe0.8O3-δ with and without nano-infiltrated PrOx and (b) SrTi0.3Fe0.55Co0.15O3-δ with and without nano-infiltrated PrOx all supported on a Ce0.9Gd0.1O2-δ electrolyte.

Figure 1
(Invited) Recent Progress in PEFC Technology and Future Direction
Authors: Kamitaka Yuji , Shinohara Akihiro , Suzuki Takahisa , Yamada Haruhiko , Kodama Kensaku , Jinnouchi Ryosuke , Morimoto Yu 
Published: February 2020

Since the inventions in 1980s of the basic structure, i.e. a layered structure of a perfluorosulfonic acid membrane and gas diffusion electrodes including Pt on carbon and an ionomer, significant advancement has been achieved and finally, commercial products are now in the market for automobile and stationary applications.
In this talk, key technologies established in this period were quickly reviewed and present status and issues were presented as well as on-going trends to address the issues.
A part of this study was financially supported by the New Energy and Industrial Technology Development Organization.
Nonlinear Time Series Analysis of Nickel in Sulfuric Acid
Authors: Clark David Q. , Wipf David O 
Published: February 2020

Nickel is one of the most important passive metals used in electrodeposition processes in the world. These processes alone consume several million metric tons of nickel yearly. Nickel is well known for its corrosion resistant properties. However, nickel does corrode in H2SO4 and can produce current or potential oscillations in potentiostatic or galvanostatic experiments.
Traditional electrochemical studies on Ni oscillating systems are performed by applying applied potential or current during the electrodissolution (corrosion) of single wire electrodes in highly concentrated solutions. External forcing, in which perturbations are applied to systems by an external source, have provided a better understanding of oscillating systems. However, little attention has been given to performing electrochemical studies on electrodeposited metals that produce oscillating systems in lower concentrations of acidic solutions (0.1 M – 1.0 M) and no attention has been given to the possibility for external forcing of these unique systems via concentration change and local heating at the electrode surface until now. The presented work examines the changes in frequency, magnitude, and shape of periodic oscillations and the change in kinetics from temperature changes due to electrical heating and external forcing by independently changing the proton concentration at a nickel electrode. This work improves the understanding of the relationship between periodic oscillation phenomena and the corrosion process of the nickel system in H2SO4.
In-Situ Ultra-Low Frequency SERS Observation at Electrified Interfaces
Authors: Ikeda Katsuyoshi 
Published: February 2020

Surface-selective spectroscopy is a powerful tool to study various interfacial phenomena such as electrochemical reactions at electrode/electrolyte interfaces. However, structural information on the solid and liquid phases next to the interface have been separately observed using different spectroscopic methods: e.g., X-ray spectroscopy for solid phases and vibrational spectroscopy for liquid phases. Recently, we have extended the detectable frequency range of surface enhanced Raman scattering (SERS) into the ultra-low frequency region down to 10 cm-1, which corresponds to THz region [1]. This enables us to observe not only molecular vibrations but also extramolecular vibrations and surface phonons of the metal lattice [2]. These information should provide deeper insight into catalytic and electrocatalytic reaction mechanisms. In this talk, we will demonstrate in-situ and simultaneous detection of vibrational information on both solid-electrode and liquid-electrolyte phases at the interface.
[1] M. Inagaki, K. Motobayashi, K. Ikeda, “Electrochemical THz-SERS Observation of Thiol Monolayers on Au(111) and (100) Using Nanoparticle-assisted Gap-Mode Plasmon Excitation” J. Phys. Chem. Lett., 8, 2017, pp. 4236-4240.
[2] M. Inagaki, K. Motobayashi, K. Ikeda, submitted.
Flexible Impedimetric Sensors for Detection of Pollutants
Authors: Stanciu Lia , Diaz Susana , Lin Li-Kai , Ulloa-Gomez Ana-Maria 
Published: February 2020

A variety of sensors have been developed at the laboratory level within the past few decades. However, very few of these reached the market and are being used today.
We used roll-to-roll processing to develop field deployable flexible electrochemical sensors for the detection of environmental pollutants such as mercury and organophoshorous pesticides. The sensors are based on injket printed interdigitated gold electrodes, which were further functionalized for detection of organophosphorous pesticides and mercury, respectively. For the pesticide sensors, a mesh of zirconium oxide fibers was deposited via roll-to-roll on the electrodes, and the response to the target was quantified impedimetrically.
Mercury ions were detected upon the functionalization of the interdigitated electrodes with specific DNA aptamers, while the impedimetric transduction was maintained.
Sensors stability, selectivity and detection limits were measured for laboratory conditions and in real food and soil samples. The sensors show similar characteristics with the state of the art in the field, are field deployable and able to be manufactured in a consistent and repeatable fashion.
Planar and out of Plane Configuration Based Flexible Sensor of PVDF Polymer
Authors: Ganguly Ronit , Acharyya Amit , Ramadurai Ranjith 
Published: February 2020

PVDF (Polyvinylidene fluoride) a piezo polymer has been a potential candidate for its functional properties and device applications like flexible sensors, energy harvesting and biomedical applications. [1] There are various methods to fabricate free standing PVDF thin films.[2] One of such is solution casting method. It is known from the literature that PVDF films synthesized from varying viscosities through solution casting method exhibits different behavioural pattern of ferroelectric polarization components.[3] The study indicated that films prepared from precursor viscosity of 2.9 Pa.s exhibits dominant out-of-Plane polarization whereas films prepared from precursor viscosity of 4.6 Pa.s exhibit dominant in-plane polarization
The orientation of these polarization components has an impact on the piezoelectric coefficient. [4] Piezoelectric coefficient is one of the important factor in deciding the efficiency and materials utilization in real time devices. The piezoelectric coefficient, d33 for the unpoled pure PVDF samples exhibiting dominant out-of-plane was found to be in the range of 0.4-4.24pm/v whereas the PFM scan shows the dominance of in-plane/planar domains indicates a significant value of d31.
In this work we have fabricated out-of-plane and planar electrode based sensors of PVDF and tested for vibration detection. Film for the planar sensor is fabricated from precursor viscosity of 4.6 Pa.s and out-of-plane sensor from precursor viscosity of 2.9 Pa.s. When the fabricated sensors were tested by finger taping, it is observed that planar configured sensor are more sensitive than out-of-plane sensor. In figure we could see the piezoresponse microscope images along with ferroelectric hysteresis loop which confirm the ferroelectric nature of PVDF films. Also response of the sensor for a given vibration caused due to finger tapping is shown from both the configuration.

REFERENCES

[1] A. Proto, B. Fida, I. Bernabucci, K. Vlach, V. Kasik, M. Penhaker, Wearable PVDF Transducer for Biomechanical Energy Harvesting and Gait Cycle Detection, IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), Kuala Lumpur ,Malaysia, 2016, 62-66.
[2] P. Martins, A.C. Lopes, S. Lanceros-Mendez, Electroactive phases of poly(vinylidene fluoride):Determination, processing and applications, Prog. Polym. Sci. 39, (2014) 683 - 706.
[3] R. Ganguly, S. Bandyopadhyay, k. Mirilaya, V. Gunasekaran, S. Bhattacharya, A. Acharyya, R. Ramadurai, Tunable polarization components and electric field induced crystallization in polyvinylidenefluoride (PVDF); a piezopolymer, Polymer Crystallization ,(2018) . DOI:10.1002/pcr2.10027.
[4] S. K. Mahadeva, J. Berring, K. Walus, B. Stoeber, Effect of poling time and grid voltage on phase transition and piezoelectricity of poly(vinyledene ﬂuoride) thin ﬁlms using corona poling, J. Phys. D:Appl. Phys, 46, (2013) 285305

Figure 1
Electrochemical Sensors to Monitor Multi-Drug Resistant Organisms in the Gut Microbiome
Authors: Argun Avni , Rana Muhit , Weber Andrew , Manoukian Mourad , Koh Andrew , Toprak Erdal 
Published: February 2020

Infections caused by multi-drug resistant organisms (MDROs) are responsible for over 2 million of hospitalization and 23,000 deaths annually in the United States, with direct financial impact of $20 billion a year. Microbiome dysbiosis (imbalance) is considered to be the main cause for MDRO colonization and the resulting infections. MDRO outbreaks need to be quickly detected and monitored for effective intervention to provide relief to the stressed patient community and healthcare facility. Unfortunately, current diagnostic methods for MDRO detection are slow and costly. Polymerase chain reaction (PCR) and enzyme immunoassay (EIA) techniques or the next generation sequencing (NGS) methods do not provide the low cost and rapid platform necessary for such MDRO pathology for a patient care facility. These methods often require several days to complete, use many reagents, and need skilled technicians in a resource intensive laboratory.
In this work, we report a rapid, accurate and cost-effective electrochemical sensor capable of MDRO detection down to 104 colony forming units (CFU)/g in mice and human stool samples. To achieve this, we utilize disposable screen printed electrodes (SPEs) modified with highly specific oligonucleotide probes capable of hybridizing (duplex formation) select target gene sequences associated with MDROs. In the presence of a redox mediator, the hybridized probe/target complex generates an electrochemical current signal that differs from a non-hybridized probe molecule. The signal is highly sensitive and selective of target gene sequences and can detect as little as 3.5 picomols of target DNA. Furthermore, the SPEs can be pre-functionalized, stored, and used when needed, reducing individual sample analysis time to less than an hour.
Several target sequences from two exemplary genes (AmpC and AcrB found in MDRO E. coli) have been identified and successfully detected in clinical stool samples with results comparable to the standard quantitative PCR method. Additional target genes associated with drug resistance (TEM-1, VanA, and SHV) have also been successfully detected in vitro and are ready to be tested in clinical samples. Our gut microbiome sensor is currently being developed for multiplexed operation to simultaneously detect up to eight MDROs genes, including the ones that are responsible for breaking down b-lactam containing antibiotics. This novel sensor platform will be an economical point-of-care device with little requirement of reagent handling or technical training.

Figure 1