Chemical Cycles Research Articles

Polymeric Materials in Speciation Analysis Based on Solid-Phase Extraction.

Speciation analysis is a relevant topic since the (eco)toxicity, bioavailability, bio (geo)chemical cycles, and mobility of a given element depend on its chemical forms (oxidation state, organic ligands, etc.). The reliability of analytical results for chemical species of elements depends mostly on the maintaining of their stability during the sample pretreatment step and on the selectivity of further separation step. Solid-phase extraction (SPE) is a matter of choice as the most suitable and widely used procedure for both enrichment of chemical species of elements and their separation. The features of sorbent material are of great importance to ensure extraction efficiency from one side and selectivity from the other side of the SPE procedure. This review presents an update on the application of polymeric materials in solid-phase extraction used in nonchromatographic methods for speciation analysis.

Manufacturing Challenges, Opportunities, and Successes for PEM Electrolysis at Scale

Hydrogen generation via electrolysis has gained much attention internationally as not only a sustainable source of fuel for the transportation, but as a carrier of energy to capture stranded renewable energy due to the carbon-free chemical cycle and response characteristics of the technology. The barrier to entry preventing this technology from being widely adopted is the overall cost associated with both the upfront capital expense as well as the operating cost incurred over the product life. The majority of this cost is driven by 1) low electrical efficiencies due to the high ohmic resistance of thicker membranes required by electrolysis systems to electrochemically compress generated hydrogen for storage and the overpotential associated with the water splitting oxygen evolution reaction (OER) catalysts typically used, 2) high cost of system and cell stack materials, which need to be durable for up to 100,000hrs at potentials approaching 2V in both reducing and oxidizing environments, and 3) the lack of a robust supply chain for high volume manufacturing to further drive down cost through economies of scale.With 95% of hydrogen currently being produced through the reformation of cheap natural gas, significant cost reductions are necessary for electrolysis to become a viable alternative to the incumbent. Commercial proton exchange membrane (PEM)-based electrolysis has reached scales of several hundred kg/day, providing a relevant pathway for industrial scale hydrogen generation with tremendous opportunity for continuing cost reduction by leveraging system and manufacturing scaling laws and advancements in PEM fuel cell materials, manufacturing, and analysis tools. Order of magnitude improvements in some of the highest cost elements are easily achievable and with more research funding being directed towards hydrogen production, the realization of these reductions is occurring at a faster rate. While many improvements in stack design and materials of construction have been identified and implemented, there are still numerous opportunities to explore that would move electrolysis towards a viable, cost-effective alternative to natural gas reformation. This talk will describe some of the areas of success, where research is still needed, and ultimately how each of these improvements translate into cost and the path to reformation parity.

Toward Stimulating the Chemistry Process for Garnet Electrolyte-Based Molten Li-S Batteries: Modulation of the End-Product in the Cathode with High Loading.

Due to their low self-discharge rate, no intermediate product dissolution in the cathode, and easy recycle of electrode materials, solid electrolyte-based molten lithium sulfur batteries can be one of the highly anticipated advanced electrochemical chemistry technologies for grid-scale energy storage. However, the actual energy density and reversibility of them still face severe challenges for low active materials loading and the inherent low conductivity of sulfur and its end-products. In this work, with the iodide modulation effect, small size (∼5 nm for the primary particles) and low relative crystallinity discharge end-products in the sulfur cathode can be formed, contributing to the immense specific capacity and reversibility. As validated by theoretical calculations, iodide ions in the homogeneous molten composite cathode display a profound comprehensive effect on the chemical reaction and cycling stability. As a result, high sulfur loading (over 80 mg cm-2) with a significant utilization rate can be achieved, corresponding to a single Li-S cell of 1.39 Ah and a volumetric energy density of 528.5 Wh L-1 based on the overall cell volume; simultaneously, a prominent cycling stability during 300 cycles along with an impressive reversibility is obtained.

Organelle-Mediated Dissipative Self-Assembly of Peptides in Living Cells.

Implementing dissipative assembly in living systems is meaningful for creation of living materials or even artificial life. However, intracellular dissipative assembly remains scarce and is significantly impeded by the challenges lying in precisely operating chemical reaction cycles under complex physiological conditions. Here, we develop organelle-mediated dissipative self-assembly of peptides in living cells fueled by GSH, via the design of a mitochondrion-targeting and redox-responsive hexapeptide. While the hexapeptide undergoes efficient redox-responsive self-assembly, the addition of GSH into the peptide solution in the presence of mitochondrion-biomimetic liposomes containing hydrogen peroxide allows for transient assembly of peptides. Internalization of the peptide by LPS-stimulated macrophages leads to the self-assembly of the peptide driven by GSH reduction and the association of the peptide assemblies with mitochondria. The association facilitates reversible oxidation of the reduced peptide by mitochondrion-residing ROS and thereby dissociates the peptide from mitochondria to re-enter the cytoplasm for GSH reduction. The metastable peptide-mitochondrion complexes prevent the thermodynamically equilibrated self-assembly, thus establishing dissipative assembly of peptides in stimulated macrophages. The entire dissipative self-assembling process allows for elimination of elevated ROS and decrease of pro-inflammatory cytokine expression. Creating dissipative self-assembling systems assisted by internal structures provides new avenues for the development of living materials or medical agents in the future.

Assessing the Technical Routes for Chemical Cycling of Waste Plastics to Light Olefins

Assessing the Technical Routes for Chemical Cycling of Waste Plastics to Light Olefins

Water in Omphacite and Garnet From Pristine Xenolithic Eclogite: T‐X‐fO2 Controls, Retentivity, and Implications for Electrical Conductivity and Deep H2O Recycling

AbstractKimberlite‐borne eclogite xenoliths having Precambrian oceanic crustal protoliths and entrained from ≥100 km depth can retain pristine geochemical features despite extended residence in the cratonic lithospheric mantle, making them valuable archives of deep chemical cycling including that of water. We determined, by Fourier Transform Infrared Spectroscopy, structural OH contents in clinopyroxene and garnet from 15 unmetasomatized eclogite xenoliths. Calculated total c(H2O) is 100–510 wt.ppm for clinopyroxene and below detection (∼2 wt.ppm) to 200 wt.ppm for garnet, while garnet δ18O, determined by Secondary Ion Mass Spectrometry, ranges from +5.0‰ to +7.3‰, (similar to high‐ and low‐temperature seawater‐altered oceanic crust). Estimated electrical conductivity in pristine eclogites increases with temperature (i.e., depth for conductive geotherms), while clinopyroxene‐garnet H2O partition coefficients decrease with increasing temperature and garnet grossular component (i.e., Ca#), similar to other incompatible components. Various considerations suggest the retention of primary H2O in the samples, likely occurring in km‐sized pods of coarse‐grained eclogite. High Al2O3 in clinopyroxene as omphacite component, stabilized during high‐pressure metamorphism, facilitates H2O uptake. Therefore, the high bulk c(H2O) estimated for samples with plagioclase‐rich, deep crustal protoliths (median 290 wt.ppm) may indicate an interaction with fluids expelled at depth from serpentinites. The c(H2O) of ancient and modern subducted bulk oceanic crust (∼220–240 wt.ppm) are similar, suggesting constant mantle ingassing since at least 3 Ga ago. This places constraints on factors, such as mantle temperatures, that determine the efficiency of deep water cycling.

Predicting snag fall in an old-growth forest after fire

BackgroundSnags, standing dead trees, are becoming more abundant in forests as tree mortality rates continue to increase due to fire, drought, and bark beetles. Snags provide habitat for birds and small mammals, and when they fall to the ground, the resulting logs provide additional wildlife habitat and affect nutrient cycling, fuel loads, and fire behavior. Predicting how long snags will remain standing after fire is essential for managing habitat, understanding chemical cycling in forests, and modeling forest succession and fuels. Few studies, however, have quantified how fire changes snag fall dynamics.ResultsWe compared post-fire fall rates of snags that existed pre-fire (n = 2013) and snags created during or after the fire (n = 8222), using 3 years of pre-fire and 5 years of post-fire data from an annually monitored, 25.6-ha spatially explicit plot in an old-growth Abies concolor–Pinus lambertiana forest in the Sierra Nevada, CA, USA. The plot burned at low to moderate severity in the Rim Fire of 2013. We used random forest models to (1) identify predictors of post-fire snag fall for pre-existing and new snags and (2) assess the influence of spatial neighborhood and local fire severity on snag fall after fire. Fall rates of pre-existing snags increased 3 years after fire. Five years after fire, pre-existing snags were twice as likely to fall as new snags. Pre-existing snags were most likely to persist 5 years after fire if they were > 50 cm in diameter, > 20 m tall, and charred on the bole to heights above 3.7 m. New snags were also more likely to persist 5 years after fire if they were > 20 m tall. Spatial neighborhood (e.g., tree density) and local fire severity (e.g., fire-caused crown injury) within 15 m of each snag barely improved predictions of snag fall after fire.ConclusionsLand managers should expect fall rates of pre-existing snags to exceed fall rates of new snags within 5 years after fire, an important habitat consideration because pre-existing snags represent a wider range of size and decay classes.

Chemical Redox Cycling in an Organic Photoelectrochemical Transistor: Toward Dual Chemical and Electronic Amplification for Bioanalysis.

The organic photoelectrochemical transistor (OPECT) has been proven to be a promising platform to study the rich light-matter-bio interplay toward advanced biomolecular detection, yet current OPECT is highly restrained to its intrinsic electronic amplification. Herein, this work first combines chemical amplification with electronic amplification in OPECT for dual-amplified bioanalytics with high current gain, which is exemplified by human immunoglobulin G (HIgG)-dependent sandwich immunorecognition and subsequent alkaline phosphatase (ALP)-mediated chemical redox cycling (CRC) on a metal-organic framework (MOF)-derived BiVO4/WO3 gate. The target-dependent redox cycling of ascorbic acid (AA) acting as an effective electron donor could lead to an amplified modulation against the polymer channel, as indicated by the channel current. The as-developed bioanalysis could achieve sensitive HIgG detection with a good analytical performance. This work features the dual chemical and electronic amplification for OPECT bioanalysis and is expected to stimulate further interest in the design of CRC-assisted OPECT bioassays.

Characterization and thermal properties of lauryl alcohol-capric acid binary mixture with hybrid-nanoparticles as phase change material for vaccine storage applications

The key challenge during vaccine cold chain logistics is maintaining a temperature range of 2–8 °C for the safe delivery of vaccines. In this study, a novel organic binary mixture of lauryl alcohol (LA) and capric acid (CA) with a weight fraction of 53:47 was developed as a phase change material (PCM) for passive cooling of vaccines during cold chain logistics. Considering the low thermal conductivity of organic PCM mixtures, carbon-metal-oxide based hybrid nanoparticles, namely GNP-Al2O3, GNP-CuO and GNP-TiO2 were chosen as thermal conductivity promoters. The hybrid nanoparticles were dispersed in a pure LA-CA binary mixture to develop hybrid nano-enhanced PCMs (HNePCMs). The chemical and thermal characterization of pure LA-CA and HNePCMs was examined. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) results reveal uniform dispersion and chemical compactness of hybrid nanoparticles in pure LA-CA. Fourier-transformed infrared (FTIR) results confirm that there is no chemical interaction between nanoparticles and LA-CA binary mixture. The pure LA-CA binary mixture possesses a melting temperature of 4.0 °C and melting latent heat of 170.7 J/g respectively. HNePCM of LA-CA/GNP-Al2O3 shows a maximum thermal conductivity enhancement of 55.7 %. However, it shows a maximum deviation in melting temperature of 8 %. Besides, LA-CA/GNP-CuO shows a minimal deviation in melting temperature and latent heat and possesses improved thermal conductivity enhancement of 46 %. Thus, a developed LA-CA/GNP-CuO mixture with good chemical, thermal stability and long-term cycle durability can be employed as an ideal material for passive vaccine cooling during cold chain logistics.

Aqueous Organic Redox-Targeting Flow Batteries with Advanced Solid Materials: Current Status and Future Perspective

Aqueous organic redox flow batteries (AORFBs) represent innovative and sustainable systems featuring decoupled energy capacity and power density; storing energy within organic redox-active materials. This design facilitates straightforward scalability, holding the potential for an affordable energy storage solution. However, AORFBs face challenges of unsatisfied energy density and stability. Redox-targeting (RT) reaction is a promising way to resolve these problems, which involves a closed-loop electrochemical–chemical cycle between soluble redox mediators and solid materials. Among all these systems, the aqueous organic redox-targeting system is the most promising due to its greater sustainability, safety, low cost, and excellent tunability when compared to non-aqueous or all-vanadium systems, especially when it comes to energy storage on a large scale. Firstly, various types of AORFBs and their characteristics are discussed and analyzed, followed by introducing the concept and the evolution of RT. In addition, advanced characterization techniques to analyze RT-based AORFBs are summarized. Finally, the challenges lying in aqueous organic redox-targeting flow batteries are stated and corresponding recommendations are provided. It is anticipated that AORFBs with advanced solid materials will provide a promising solution for large-scale energy storage.

Chemical-Chemical Redox Cycle Signal Amplification Strategy Combined with Dual Ratiometric Immunoassay for Surface-Enhanced Raman Spectroscopic Detection of Cardiac Troponin I.

Improving the sensitivity and reproducibility of surface-enhanced Raman spectroscopy (SERS) methods for the detection of bioactive molecules is crucial in biological process research and clinical diagnosis. Herein, we designed a novel SERS platform for cardiac troponin I (cTnI) detection by a chemical-chemical redox cycle signal amplification strategy combined with a dual ratiometric immunoassay. First, ascorbic acid (AA) was generated by enzyme-assisted immunoreaction with a cTnI-anchored sandwich structure. Then, oxidized 4-mercaptophenol (ox4-MP) was reacted with AA to produce 4-mercaptophenol (4-MP). Quantitative analysis of cTnI was realized by a Raman signal switch between ox4-MP and 4-MP. Specifically, AA could be regenerated by reductant (tris(2-carboxyethyl) phosphine, TCEP), which in turn produced more signal indicator 4-MP, causing significant signal amplification for cTnI analysis by SERS immunosensing. Moreover, a dual ratiometric-type SERS method was established with the intensity ratio I1077/I822 and I633/I822, which improved the reproducibility of the cTnI assay. The excellent performance of the chemical-chemical redox cycle strategy and ratio-type SERS assay endows the method with high sensitivity and reproducibility. The linear ranges of cTnI were 0.001 to 50.0 ng mL-1 with detection limits of 0.33 pg mL-1 (upon I1077/I822) and 0.31 pg mL-1 (upon I635/I822), respectively. The amount of cTnI in human serum samples yielded recoveries from 89.0 to 114%. This SERS method has remarkable analytical performance, providing an effective approach for the early diagnosis of cardiovascular diseases, and has great latent capacity in the sensitive detection of bioactive molecules.

Spatial variation of sulfur in terrestrial ecosystems in China: Content, density, and storage

Sulfur (S) is an important macronutrient that is widely distributed in nature. Understanding the patterns and mechanisms of S dynamics is of great significance for accurately predicting the geophysical and chemical cycles of S and formulating policies for S emission and management. We systematically investigated and integrated 17,618 natural plots in China's terrestrial ecosystems and built a S density database of vegetation (including leaves, branches, stems, and roots) and surface soil (0–30 cm depth). The biogeographic patterns and environmental drivers of the S content, density, and storage in the vegetation and soil of terrestrial ecosystems were explored. Vegetation and soil were the major components of terrestrial ecosystems, storing a total of 2228.77 ± 121.72 Tg S, with mean S densities of 4.32 ± 0.04 × 10−2, and 267.93 ± 14.94 × 10−2 t hm−2, respectively. The forest was the most important vegetation S pool and their S storage accounted for about 55.28 % of the total vegetation S storage, whereas soil S pools of croplands and other vegetation types (e.g., deserts and wetlands) accounted for about 63.18 % of the total soil S storage. The mean S density (2.18 ± 0.02 × 10−2 t hm−2) and S storage (12.45 ± 0.31 Tg) of plant roots were significantly higher than those of other organs. The spatial variation in the S density was mainly regulated by climate and soil properties, reflecting the physiological adaptation mechanisms of plants by adjusting the S uptake and distribution to cope with climate change. In this study, the spatial patterns of S density and storage in vegetation and soil in terrestrial ecosystems of China and their response to environmental factors on a national scale were systematically studied. The results provide insights into the biological functions of S and its role in plant–environment interactions.

Recent advances in the biodegradation of polyethylene terephthalate with cutinase-like enzymes.

Polyethylene terephthalate (PET) is a synthetic polymer in the polyester family. It is widely found in objects used daily, including packaging materials (such as bottles and containers), textiles (such as fibers), and even in the automotive and electronics industries. PET is known for its excellent mechanical properties, chemical resistance, and transparency. However, these features (e.g., high hydrophobicity and high molecular weight) also make PET highly resistant to degradation by wild-type microorganisms or physicochemical methods in nature, contributing to the accumulation of plastic waste in the environment. Therefore, accelerated PET recycling is becoming increasingly urgent to address the global environmental problem caused by plastic wastes and prevent plastic pollution. In addition to traditional physical cycling (e.g., pyrolysis, gasification) and chemical cycling (e.g., chemical depolymerization), biodegradation can be used, which involves breaking down organic materials into simpler compounds by microorganisms or PET-degrading enzymes. Lipases and cutinases are the two classes of enzymes that have been studied extensively for this purpose. Biodegradation of PET is an attractive approach for managing PET waste, as it can help reduce environmental pollution and promote a circular economy. During the past few years, great advances have been accomplished in PET biodegradation. In this review, current knowledge on cutinase-like PET hydrolases (such as TfCut2, Cut190, HiC, and LCC) was described in detail, including the structures, ligand-protein interactions, and rational protein engineering for improved PET-degrading performance. In particular, applications of the engineered catalysts were highlighted, such as improving the PET hydrolytic activity by constructing fusion proteins. The review is expected to provide novel insights for the biodegradation of complex polymers.

Sediment biogeochemistry and relationship with arsenic in the Kuitun River Basin, Xinjiang, China: influences of microbial community structure and characteristics on arsenic migration

The microorganisms in sediments play a significant role in Arsenic (As) migration in groundwater systems. However, the impact mechanisms of microbial community structure on As release and enrichment are not completely clear. In this study, the community structure and characteristics of microorganisms in sediments of the Kuitun River Basin were first investigated through field investigation, high-throughput sequencing, and microbial analysis. The obtained results showed that Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were the dominant phyla in the sediments, accounting for 30.23%–87.87%, 3.280%–65.22%, 1.71%–14.37%, and 0.46%–16.67%, respectively. Whereas, Arthrobacter, Acinetobacter, Pseudomonas, and Hydrogenophaga were the main genera in the collected sediments from the Kuitun River Basin, accounting for 1.81%–60.13%, 0.70%–77.24%, 0.21%–35.5%, and 0.38%–26.27%, respectively. Arthrobacter can increase the As contents in the sediments. In contrast, Acinetobacter can both inhibit and promote the release of As from the sediments, while Pseudomonas and Hydrogenophaga can only inhibit the release of As from the sediments. The Variance Inflation Factor (VIF) suggested that Ca, Mg, Mn, Cu, and As were highly correlated with each other. The distance-based redundancy analysis (Db-RDA) analysis demonstrated significant influences of the sediment chemical properties on the microbial activity and community structure in the sediments, according to the following order: Ca > Cu > Mn > Mg > As. Ca2+ and Mn2+ in the environment can influence the growth and metabolism of microorganisms, thus affecting the redox environment and As release from sediments. This study confirmed the interaction that may exist between microorganisms and As. Moreover, this study not only confirmed the interaction between microorganisms and As, but also provided a comprehensive understanding of the effects of the microbial community on the chemical cycle of the groundwater system in the Kuitun River basin. The analysis of the influences of the microbial community on sediment As provided further insights into As release from sediments and As enrichment in groundwater in the study area.

Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges.

Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

Die Rolle von unreaktiven Polyanionen in aktiven, chemisch regulierten komplexen Koazervaten

AbstractKomplexe Koazervation beschreibt die Flüssig‐Flüssig‐Phasentrennung entgegengesetzt geladener Polymere. Aktive Koazervate sind Tröpfchen, in denen die Affinität eines der Elektrolyte durch chemische Reaktionen gesteuert wird. Diese Tröpfchen sind besonders interessant, weil ihre Eigenschaften durch die Reaktionskinetik streng reguliert werden. Sie dienen beispielsweise als Modell für membranlose Organellen, die häufig auch durch biochemische Transformationen, wie z. B. posttranslationale Modifikationen, gesteuert werden. Sie sind auch ein gutes Modell für Protozellen oder könnten zur Synthese von künstlichem Leben verwendet werden – sie entstehen spontan als Reaktion auf Reagenzien, konkurrieren und zerfallen, sobald alle Nährstoffe verbraucht sind. Allerdings ist die Rolle der unreaktiven Bausteine, z. B. der Polymere, bisher kaum verstanden. Mit unserer Arbeit zeigen wir die wichtige Rolle des unreaktiven Polyanions unserer chemisch betriebenen Koazervattropfen. Wir zeigen, dass das Polyanion den Lebenszyklus der resultierenden Tröpfchen drastisch beeinflusst, ohne den chemischen Reaktionszyklus selbst zu beeinflussen – entweder sind sie sehr dynamisch oder lösen sich nur verzögert auf. Darüber hinaus leiten wir den Mechanismus dahinter ab und zeigen, wie Additive und rationales Polymerdesign dazu beitragen können, die gewünschten Lebenszyklen von Koazervatemulsionen zu erzeugen.

Phages in vermicomposts enrich functional gene content and facilitate pesticide degradation in soil

Organic fertilizer microbiomes play substantial roles in soil ecological functions, including improving soil structure, crop yield, and pollutant dissipation. However, limited information is available about the ecological functions of phages and phage-encoded auxiliary metabolic genes (AMGs) in orga9nic fertilizers. Here we used a combination of metagenomics and phage transplantation trials to investigate the phage profiles and their potential roles in pesticide degradation in four organic fertilizers from different sources. Phage annotation results indicate that the two vermicomposts made from swine (PV) and cattle (CV) dung had more similar phage community structures than the swine (P) and cattle (C) manures. After vermicomposting, the organic fertilizers (PV and CV) exhibited enriched phage-host pairings and phage AMG diversity in relative to the two organic fertilizers (P and C) without composting. In addition, the number of broad-host-range phages in the vermicomposts (182) was higher than that in swine (153) and cattle (103) manures. Notably, phage AMGs associated with metabolism and pesticide biodegradation were detected across the four organic fertilizers. The phage transplantation demonstrated that vermicompost phages were most effective at facilitating the degradation of pesticide precursor p-nitrochlorobenzene (p-NCB) in soil, as compared to swine and cattle manures (P < 0.05). Taken together, our findings highlight the significance of phages in vermicompost for biogeochemical cycling and biodegradation of pesticide-associated chemicals in contaminated soils.

Multiphysics Modeling of Solid Oxide Iron Air Battery with New Catalyst and Proton Conductor Oxide Support

Long-duration energy storage (LDES) (10+ hours) is widely regarded as an enabling technology to deepen the penetration of renewable energy into the commercial utility market. However, the current storage technologies cannot achieve LDES’s duration requirement at a competitive cost. Therefore, new LDES technologies are highly sought after in recent years. Solid oxide iron air battery is a newly emerging battery based on oxide-ion chemistry and stores energy in energy-dense solid iron. Our recent results have shown that the battery in a laboratory size (f1”) delivers 12.5-hour storage per cycle for 20 cycles with high energy capacity and round-trip efficiency. This presentation focuses on the description of a high-fidelity 2D axis symmetrical multi-physics model to simulate the performance of a solid oxide iron air battery. The model battery system consists of an anode-supported solid oxide cell and energy storage unit (ESU) of iron bed with a proton conducting oxide BaZr0.4Ce0.4Y0.1Yb0.1O3 (BZC4YYb) based support and iridium as a catalyst. The Multiphysics model encompasses charge transfer, mass transport, and chemical redox kinetic cycle occurring across all components of the battery and is validated with experimental results. The kinetic JMA (Johnson-Mehl-Avrami) model is used for describing the oxidation and reduction kinetics of Fe-BZC4YYb-IrO2 ESU. The motivation for combing the Ir catalyst with proton conductor oxide support in ESU is to boost the sluggish FeOx reduction kinetics. Compared to the baseline ESU, i.e. Fe2O3/ZrO2, the newly developed BZC4YYb-IrO2 shows great catalytic activity toward FeOx reduction, thus allowing SOIAB to operate at 500-550oC with excellent capacity, stability, and high round trip efficiency. The presentation will also show the experimental data of improved reduction kinetic rate of Fe-BZC4YYb-IrO2 over the baseline Fe2O3/ZrO2.

(Invited) Decoupled Water Splitting for Green Hydrogen Production: Reshaping Water Electrolysis

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).

An Interference-Free Voltammetric Method for the Detection of Sulfur Dioxide in Wine Based on a Boron-Doped Diamond Electrode and Reaction Electrochemistry.

This paper describes a new, simple, and highly selective analytical technique for the detection of sulfur dioxide in wine, as a real sample with a relatively complicated matrix. The detection of the above analyte was based on the electrogeneration of iodine from iodide on a boron-doped diamond electrode, without modifications, in the presence of 0.1 mol dm-3 HClO4 as a supporting electrolyte. The electrogenerated iodine reacted with sulfur dioxide, forming iodide ions and sulfuric acid (i.e., a Bunsen reaction). The product of this reaction, the iodide ion, diffused back to the surface of the boron-doped diamond electrode and oxidized itself again. This chemical redox cycling enhanced the voltammetric response of the boron-doped diamond electrode. The selectivity of the determination was assured using NaOH and formaldehyde during sample preparation, and a blank was also measured and taken into account. The detection limit was estimated to be 10-6-10-7 mol dm-3. However, the content of sulfur dioxide in wine is significantly higher, which can lead to more accurate and reliable results.