bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) hybrid Nanomanufacturing of Self-Powered Human-Integrated Sensors
Authors: Wu Wenzhuo 
Published: September 2023

The seamless and adaptive interactions between functional devices and their environment (e.g., the human body) are critical for advancing emerging technologies, e.g., wearable devices, consumer electronics, and human-machine interface. The state-of-the-art technologies, however, require a complex integration of heterogeneous components to interface the mechanical stimulus which is ubiquitous and abundant in the above applications. These limitations have severely hampered the advancement and broader utilization of related technologies. Moreover, all existing technologies require a power source, which complicates the system design and limits operation schemes.
In this talk, I will discuss our recent progress in developing self-powered human-integrated sensors through the hybrid nanomanufacturing of heterostructured devices. This new class of wearable devices are conformable to human skins and can sustainably perform self-powered, non-invasive functions, e.g., physiological monitoring and gesture recognition, by harvesting the operation power from the human body. This research is expected to have a positive impact and immediate relevance to many societally pervasive areas, e.g., telehealth, consumer electronics, and robotics.
Fabrication of Aptamer-based Field Effect Transistor Sensors for Detecting Mercury Ions
Authors: Wang Yu-Lin , Zeng Guan-Cheng , Lee Chun-Ta , Lin Chia Kai , Kuo Tzu-Han , Paulose Akhil K , Lin Zong-Hong , Hung Sheng-Chun 
Published: September 2023

With the rapid development of industry, the pollution of the environment is becoming more and more serious. Among them, water pollution is one of the most serious problems, and polluted water sources often contain heavy metal ions such as mercury, chromium, lead, chromium, arsenic, etc. Which in turn affect our irrigation, breeding, food, and drinking, and finally cause physical harm. Mercury is still widely used today. For example, mercury and mercury compounds are used as catalysts in the plastics industry. Mercury is still widely used today. For example, mercury and mercury compounds are used as catalysts in the plastics industry. Some toxic pesticides also contain mercury. Mercury is used in daily life in fluorescent lamps, batteries, thermometers, medical amalgams, etc.
Mercury pollution can be divided into two categories: organic mercury and inorganic mercury. Prolonged exposure to mercury can cause paralysis and a progressive loss of sense of touch, sight, hearing, or taste. Other more common neurological symptoms include memory and balance impairment, insomnia, hand tremors, and behavioral disturbances. Detecting the mercury content in water usually requires large-scale laboratory instruments for measurement, costing a lot of money and time.
In this study, a specific aptamer is combined with a field-effect transistor to form an aptamer field-effect transistor by utilizing the properties of thymine-Hg(II)-thymine (T-Hg(II)-T) coordination chemical bonds. A highly selective and sensitive mercury ion sensor was achieved by using N-channel depletion-mode MOSFETs with APTAMER-modified gates. For the Aptamer-modified FET sensor, a detection limit of 0.2 PPM was achieved using a 500 μM × 500 μM gate sensing area. Biosensors realize reduced size, shorter detection speeds, cost savings, and high detection of limit sensors. Therefore, the determination of heavy metal ions in the environment by simple and easy-to-use instruments is of great significance for disease prevention.

Figure 1
The Impact of Cation Contamination on Proton Exchange Membrane Water Electrolyzer (PEMWE)
Authors: Sun Qiang , Yang Fan , Jia Qingying , Mittelsteadt Cortney 
Published: September 2023

Hydrogen has emerged as a promising clean energy carrier and source alternative to fossil fuels(1). Mass production of cost-effective hydrogen without pollution is essential for the so-called hydrogen economy and the hydrogen produced in this process is called green hydrogen(2). It uses renewable energy such as wind energy and solar energy to generate electricity and produce hydrogen via water electrolysis, with net-zero carbon emissions. The proton exchange membrane water electrolyzer (PEMWE) is one of the most commercially available devices for water electrolysis. A membrane electrode assembly (MEA), which is laminated from an anode, cathode, and proton exchange membrane, is prone to poor performance and low lifetime if exposed to cation contamination due to the chemical properties of the materials, such as the negatively charged polymer side chain and low potential on the cathode. Therefore, it requires ultra-pure water in the operation condition.
Different cations may bring different challenges to the PEMWE. For example, some transition metals, such as Fe2+, once introduced into the membrane, may catalyze the chain formation of radicals (×OH, ×OOH, etc.) due to the Fenton reaction(3), which will cause the decomposition of the membrane. In addition, some common cations that exist in drinking water, such as Ca2+, Na+, and Mg2+, will migrate onto the cathode through the membrane and block the active sites of the catalyst(4). Moreover, typical radical scavengers such as Ce, may migrate through the membrane during the operation process(5) and become a source of contamination due to their mobility in the MEA.
In this study, we will investigate the impact of different concentrations of contamination, such as Ca2+ on the polarization curve of PEMWC and discuss the possible influence on its hydrogen crossover. To further clarify the contamination impact on the cathode, the performance of MEAs with different catalyst loadings on the cathode when subjected to cations, will be presented and discussed. In addition, several analytical instruments, such as ion chromatography (IC), inductive coupled plasma mass spectroscopy (ICP-MS), and thermo-gravimetric analysis (TGA) will be utilized to gain deeper insight into the degradation process of these contaminated MEAs.

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Numerical Measurement of the Effective Electrical Conductivity of Electrolyte-Gas Bubble Dispersions
Authors: Pari Arvind , Padding Johan Tiemen , Hartkamp Remco 
Published: September 2023

Bubble formation during water electrolysis is inevitable. Apart from mass and heat transfer limitations, the presence of these bubbles causes a decrease in the local electrical conductivity of the electrolyte, thereby contributing further to the ohmic resistance of the system. Experimental and theoretical studies have shown that the effective electrical conductivity of an electrolyte-gas bubble dispersion depends on the volume fraction of gas bubbles. However, these studies do not provide insight into the dependence of conductivity on the geometric and spatial parameters of the dispersion, such as the size distribution of the bubbles or their spatial arrangement.
Experimentally, the conductivity of such dispersions can be measured using the four-electrode conductivity measurement technique. In this talk, I will present a numerical rendition of this experimental technique to measure the conductivity of an electrolyte dispersed with gas bubbles, using the lattice Boltzmann method. The computational nature of the method lends itself well to investigating systems with different bubble size distributions and spatial configurations. The model also offers the flexibility to specify the surface charge density of the dispersed bubbles. The visualization of the ionic flux around these dispersed bubbles provides insights into the motion of ions along the paths of least resistance, and therefore a better understanding of the behavior of such systems.
The effective conductivity of bubble dispersions with varying degrees of randomness in their spatial arrangement has been measured, ranging from a regularly packed array of bubbles to a completely random packing. We observed that the numerically measured conductivity deviates from that predicted theoretically at high bubble volume fractions. Moreover, for the same bubble volume fraction, different spatial arrangements yield different values of conductivity, thus highlighting the influence of spatial arrangement of the bubbles on the effective conductivity of the dispersion. Additionally, the spread (standard deviation) of the numerically measured conductivity about the mean value for a given bubble volume fraction is observed to be larger at moderate volume fractions, in comparison to very dilute and densely packed dispersions. This can be explained by the fact that at moderate bubble volume fractions, there is a larger probability for the formation of random bubble clusters that hinder the movement of ions. Such clusters are unlikely in dilute cases and are universal in the dense limit, and as a consequence, less variation in the resulting effective conductivity is observed for the two limiting cases. This furthermore indicates the importance of spatial arrangement on the effective conductivity of such dispersions.
(Invited) Decoupled Water Splitting for Green Hydrogen Production: Reshaping Water Electrolysis
Authors: Rothschild Avner , Dotan Hen , Landman Avigail , Grader Gideon 
Published: September 2023

Green hydrogen produced by splitting water molecules into hydrogen and oxygen using electricity from renewable energy sources is essential to reduce CO2 emissions, especially in hard-to-abate industrial sectors such as steelmaking and ammonia production. It is a critical component in the energy transition to fight climate change. The present technologies for green hydrogen production are alkaline and polymer electrolyte membrane water electrolysis. One thing in common to these technologies is the coupling between the hydrogen and oxygen evolution reactions (HER and OER, respectively), where both reactions occur concurrently in the same electrolytic cell. Therefore, a membrane or diaphragm divides the cell into two compartments to avoid hazardous H2/O2 mixing. This membrane architecture complicates the electrolyzers construction by adding gaskets and compression sealing to prevent H2/O2 crossover. This adds substantial costs and limits operation at high pressures and low-purity water. In addition, substantial energy losses, mostly due to the difficult OER, increase the cost of energy in this energy intensive technology. These drawbacks give rise to high cost of green hydrogen.
To overcome these challenges, we developed alternative processes that decouple the generation of hydrogen and oxygen into two consecutive stages (time separation),1 or two cells (space separation),2 avoiding the need for membrane and sealing. In addition, we divided the OER, a difficult electrochemical reaction that requires four electrons and protons to generate an oxygen molecule on a single atomic reaction site, into two sub-reactions that occur on four sites, thereby enabling facile reactions and reducing the energy losses in water electrolysis. An ultrahigh efficiency of nearly 99% was demonstrated at lab scale,2 and we expect reaching above 90% at system scale. To bring this breakthrough process to reality we established H2Pro, an Israeli startup company that aims to produce green hydrogen at $1/kg by the end of this decade, based on our invention.3

Landman et al., Photoelectrochemical water splitting in separate oxygen and hydrogen cells, Nature Materials 16, 646–651 (2017).

Dotan et al., Decoupled hydrogen and oxygen evolution by a two-step electrochemical – chemical cycle for efficient overall water splitting, Nature Energy 4, 786–795 (2019).

Rothschild et al., Methods and system for hydrogen production by water electrolysis, United States Patent No. 2020/0040467 A1 (2020).
Comparative Studies of Ir-Based PEM Electrolyzers Via Operando ‘Tender’ X-Ray AP-XPS
Authors: Hamlyn Rebecca , Crumlin Ethan J. 
Published: September 2023

Ir-based catalysts are considered the state-of-the-art cathode material for the oxygen evolution reaction (OER) in water splitting devices. However, large scale hydrogen production from such devices will require reduced Ir loadings and/or new materials due to factors such as Ir scarcity, cost and loss during electrolysis operation. In the hopes of enabling progress of rational design for OER catalysts, effective characterization of the electrode-liquid interface is crucial. Synchrotron-based X-ray Photoelectron Spectroscopy (XPS) offers a versatile way to obtain surface chemical and elemental characterization of these materials. The use of X-rays in the ‘tender’ regime (~2-6 keV) allows for deeper probing than the conventional ‘soft’ x-ray (< 2000 eV) set up that is common at synchrotrons and lab-based sources. The photoelectrons generated from tender x-rays have enough energy to penetrate tens of nanometers through low density components such as a layer of liquid or polymeric electrolyte. This opens the door to access the chemistry at the interface of liquid and ionomer electrolyte-electrocatalyst materials. With the use of a fully operational two-electrode system, we are able to study these membrane electrode assemblies under active water splitting conditions.
My talk will highlight recent AP-XPS results on iridium-based polymer electrolyte membranes for water splitting. With application of elevated potential, we can correlate the iridium valency and surface species with the appearance of product traces in a mass spectrum. I will show trends within and between Ir catalyst types that lend to a better understanding of these OER cathodes.

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(Invited) Green Hydrogen R&D in South Africa
Authors: Bessarabov Dmitri 
Published: September 2023

For decades, proton-exchange membrane (PEM) water electrolysis (WE) has been used mainly for oxygen generation in anaerobic environments. Over the past two decades, however, it has been increasingly used for hydrogen generation in the industrial sector at various and increasing scale. The PEMWE technology is also considered as a key one in the frame of the ongoing energy transition if the process of hydrogen generation by means of WE is linked to renewable energy sources, such as wind, solar, etc.
Among other existing water electrolysis technologies, such as alkaline, solid oxide, the technology based on proton-exchange membranes has received a great deal of interest in South Africa. One of the reasons is endowment of South Africa with its PGM resources, such as platinum (Pt) and iridium (Ir) that are used in PEM water electrolysis (WE) catalytic components. As it is known, PEMWE technology is very well suited to accommodate intermittency of energy supply associated with renewables. PEMWE technology can also deliver relatively high-pressure hydrogen gas of high purity. South Africa has also superior endowment of both onshore wind and solar. It is known thar renewable energy (RE) is one of the largest operational cost components in the production of green hydrogen. Other factors contributing to the interest in green hydrogen water electrolysis technology in South Africa that are not obvious, but important, include large tracts of sparsely populated land with little alternative use, which can be dedicated for RE production. South Africa also has a suitable geographical position with deep water ports for the potential export of large quantity of hydrogen and its derivatives such as ammonia.
Approximately 15 years ago South African Government approved national program HySA: Hydrogen South Africa that resulted in developing expertise and capacity to conduct research, development, and earlier commercial activities around green hydrogen production by means of water electrolysis. These activities include development of local IP at the components, stack and system levels. Recently, a number of “catalytic” projects have been identified in order to increase a demand in green hydrogen and stimulate investments.
Recently, an international R&D project between South Africa and Japan was launched to develop further expertise in both green hydrogen and ammonia technologies [1]. Most recently, large companies, such as SASOL, made commitments to lead green hydrogen production at a large scale for the variety of applications, aiming at decarbonisation of mining and petrochemical sectors [2]. On the Governmental level, South Africa recently has approved its national hydrogen road map [3].
This talk will provide a comprehensive update on the research, technology, and commercialisation activities in South Africa in the area of green hydrogen production.
(Invited) Advances in Composite Membranes Design and Scale up for Proton Exchange Membrane Water Electrolysis
Authors: Agapov Alexander , Kobaisy Amr , Wilbert Christin , McCloskey Ellie , Abraham Prashanth , Johnson Raya , Chen Yingying , Kiernan Paul , Gardner John , Hamamoto Taichi 
Published: September 2023

Hydrogen is proposed as a future solution for a global, sustainable energy network, allowing optimization of energy efficiency while dramatically reducing emissions and decarbonizing the economies.
Lack of scaled, cost-effective environmentally friendly methods of hydrogen generation and infrastructure is a major challenge for widespread adoption of hydrogen for transportation, energy grid, integration with chemical processes, and plants.
Water electrolysis (WE) method of hydrogen generation and its integration into infrastructure is therefore rapidly gaining industrial interest all around the world.
This talk will focus on the challenges in low temperature proton exchange membrane (PEM) WE systems, particularly on design of composite PEM that can enable high efficiency, low total-cost-of-ownership WE systems that in turn enable lower levelized cost of hydrogen.
Applying the fundamental knowledge generated in fuel cell research with further tailoring of material properties to the needs of WE generated membranes with the thickness in the range of 50 micron that can withstand more than 400psi differential pressure, while possessing only half of the proton resistance of an industry benchmark non-reinforced membranes. These advancements enable high pressure, high current density operation of a WE system. We will also discuss how Gore leverages its fuel cell platform with robust supply chain developed over last 20 years for the scale-up of these novel WE PEM composites.
(Invited) Extended Thin Film Platinum Group Metal Electrocatalysts with Different Mesoscale Morphologies
Authors: Arges Christopher G. , Bhattacharya Deepra 
Published: September 2023

The lack of sufficiently active oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is a bottleneck to the proliferation of PEM fuel cells and water electrolyzers. Commercially available PGM electrocatalysts fail to attain DOE technical targets due to instabilities and activity losses incurred at low loadings. Morphology control of PGM nanostructures is an enticing route towards activity and stability enhancements of electrocatalysts, but not much is known about the structure-property relationships between PGM mesoscale geometry (5 to 100 nm) and their activity and stability.
This talk presents our work on model Pt extended surface electrocatalysts of tunable feature sizes and morphologies prepared from self-assembled block copolymer templates. The morphology, either perpendicular lamellae, cylinders, or perforated cylinders, of the extended surface electrocatalyst was controlled by the block copolymer volume fraction. The periodic lateral feature sizes (10 to 40 nm in this work) were controlled by the block copolymer degree of polymerization. The self-assembled block copolymers were transformed into extended surfaces using sequential infiltration synthesis to prepare aluminum oxide followed by reactive ion etching to remove the block copolymer template. Pt was sputtered onto the aluminum oxide supports. ORR data in a RDE with the new extended nanostructured thin films of Pt showed mass activity values of 0.35 A mgPt-1 to 0.46 A mgPt
-1 at 0.9 V vs. RHE. The measured electro-chemically active surface area (ECSA) values obtained from hydrogen underpotential deposition were 64 to 70 m2 gPt
-1. The lower values hailed from lamellae morphology while the larger values corresponded to a cylindrical morphology. The measured mass activity values, which have no cobalt or nickel additives and are unoptimized and display competitive mass activity values for ORR. We envision that the block copolymer templated extended surfaces could be an alternative to 3M’s state-of-the-art nanostructured thin film technology.
Effects of Porous Transport Layer Coating Inhomogeneities on PEM Water Electrolyzer
Authors: Liu Chang , Wrubel Jacob A , Padgett Elliot , Bender Guido 
Published: September 2023

The porous transport layer (PTL) is a critical component of polymer electrolyte membrane (PEM) water electrolyzers, transporting water to the anode catalyst layer, conducting electrons, and removing the produced oxygen. Ti materials such as felts, mesh, and sintered powders are commonly used as PTLs at the anode due to the good corrosion resistance and conductivity of Ti. However, Ti forms an electrically resistive oxide surface layer that has detrimental effects on the performance and durability of PEM electrolyzer cells. In order to permit the use of Ti PTLs in PEM electrolyzers, platinum group metals (PGMs) such as Pt and Ir can be used as a conductive, protective layer [1-3]. However, use of PGM coatings adds to the cost of PEM electrolyzers, and it is likely that future systems will use thinner coatings to minimize cost. To implement the PEM water electrolysis on a larger scale, it is essential to minimize the cost of mass-manufactured cell components while ensuring that inhomogeneities do not adversely affect the performance and durability of the cell and ultimately the stack. Improved understanding of impact of inhomogeneities on cell performance and durability is key to enabling this goal.
This study investigates the impacts of PTL coating inhomogeneities on the performance of PEM water electrolyzers. Coating inhomogeneities of various geometries were artificially made on Ti felt PTLs to investigate the effects on the cell performance and understand fabrication tolerances. In addition, a model is developed to analyze the impacts of coating geometry on the surface current density distribution and local electric potential of the cell.

Reference

Kang, Z., et al., Effects of interfacial contact under different operating conditions in proton exchange membrane water electrolysis. 2022. 429: p. 140942.

Liu, C., et al., Constructing a Multifunctional Interface between Membrane and Porous Transport Layer for Water Electrolyzers. 2021. 13(14): p. 16182-16196.

Liu, C., et al., Exploring the Interface of Skin
‐Layered Titanium Fibers for Electrochemical Water Splitting. Advanced Energy Materials, 2021. 11(8): p. 2002926.