Achim Wechsung

📢 NOMATEN published a new paper entitled: Computational modeling of CH4 and CO2 adsorption on monolayer graphenylene: Implications for optoelectronic properties and hydrogen production 👥 Authors: Amil Aligayev (University of Science and Technology of China, NOMATEN), Javier Dominguez( National Centre for Nuclear Research), Muralidhar Chourashiya, Stefanos Papanikolaou(NOMATEN), Qiang Huang (Hefei Institutes of Physical Science, Chinese Academy of Sciences) 💡 Abstract: #Graphenylene (GP) is a two–dimensional #carbon allotrope with a hexagonal lattice structure containing periodic pores. The unique arrangement of GP offers potential applications in electronics, #optoelectronics, #energy storage, and #gasseparation. Specifically, its advantageous electronic and optical properties, make it a promising candidate for #hydrogen production and advanced electronic devices. In this study, we employ a computational chemistry–based modeling approach to investigate the adsorption mechanisms of CH4 and CO2 on monolayer GP, with a specific focus on their effects on optical adsorption and electrical transport properties at room temperature. To simulate the adsorption dynamics as closely as possible to experimental conditions, we utilize the self–consistent charge tight–binding density functional theory (SCC–DFTB). Through semi–classical molecular dynamics (MD) simulations, we observe the formation of H2 molecules from the dissociation of CH4 and the formation of CO + O species from carbon dioxide molecules. This provides insights into the adsorption and dispersion mechanisms of CH4 and CO2 on GP. Furthermore, we explore the impact of molecular adsorption on optical absorption properties. Our results demonstrate that CH4 and CH2 affects drastically the optical adsorption of GP, while CO2 does not significantly affect the optical properties of the two–dimensional material. To analyze #electrontransport, we employ the open–boundary non–equilibrium Green's function method. By studying the conductivity of GP and #graphene under voltage bias up to 300 mV, we gain valuable insights into the electrical transport properties of GP under optical absorption conditions. The findings from our computational modeling approach might contribute to a deeper understanding of the potential applications of GP in #hydrogenproduction and advanced electronic devices. https://lnkd.in/dF99w8qp

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Exciting news! Our collaborative review article on "Structural engineering of metal oxyhydroxide for electrochemical energy conversion and storage" has just been published in Coordination Chemistry Reviews. This comprehensive article discusses the latest advances in metal oxyhydroxides and their composites for applications in supercapacitors, alkali metal ion batteries, hydrogen evolution reaction, oxygen evolution reaction, and overall water splitting. Key highlights: - Systematic overview of mono-, bi-, and mixed-metal oxyhydroxides - In-depth look at design and synthesis strategies for controlled properties - Analysis of structure-property relationships for optimized performance - Discussion of current challenges and future directions We are providing 50 days' free access to the final published version. Just click this personalized link before June 19, 2024 to read the full article with no registration or fees required: https://lnkd.in/gWZTvZ7G We believe these insights will guide further advancement of metal oxyhydroxide materials for sustainable energy technologies.

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Machine learning to predict activation energies? Check out the paper by Dion Vlachos and colleagues for developing models to predict activation energies of C-C and C-H scission in C1 to C6 species in hydrogenolysis reactions on Ru, Pt, and Rh. https://lnkd.in/enZCa26P

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In this recent paper, Dr. Jay (Wo Jae) Lee and Prof. John Sutherland explore an innovative method for predicting the time to failure (TTF) of rotating machinery through dynamic feature extraction combined with Gaussian process regression. This approach optimizes prognostic accuracy by leveraging historical health indicator values to forecast machinery failures with quantified uncertainty, ensuring more reliable and efficient predictive maintenance strategies in manufacturing plants. The results from several run-to-failure trials demonstrate the method's effectiveness in predicting accurate TTF, making it a valuable asset for industries relying heavily on machinery uptime and maintenance optimization. https://lnkd.in/eRtNGZgh

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New Article Alert: “High Voltage Electrolyte Design Mediated by Advanced Solvation Chemistry Toward High Energy Density and Fast Charging Lithium-Ion Batteries” @Advanced Energy Materials. https://lnkd.in/gfSMjiwC Electrolyte is critical for transporting lithium-ion (Li+) in lithium-ion batteries (LIBs). However, there is no universally applicable principle for designing an optimal electrolyte. In most cases, the design process relies on empirical experiences and is often treated as highly confidential proprietary information. In the article, a solvation structure-related model for the quantitative design of electrolytes is introduced, focusing on the principles of coordination chemistry. As a paradigmatic example, a high-voltage electrolyte (i.e., 4.5 V vs anode) aimed at achieving a high energy density and fast charging LIB, which is specifically composed of an emerging, well-constructed hybrid hard carbon-silicon/carbon-based anode, and lithium cobalt oxide cathode, is developed. Not only the functions of each electrolyte component at the molecular scale within the Li+ solvation structure are analyzed but also an interfacial model is introduced to elucidate their relationship with the battery performance. This study represents a pioneering effort in developing a methodology to guide electrolyte design, in which the mutual effects of the Li+ de-solvation process and solid electrolyte interface (SEI) on the electrode surface are explored concurrently to understand the root cause of superior performance. The innovative approach presented in the paper, establishes a new paradigm in electrolyte design, providing valuable insights at the molecular level. Jawaharlal Nehru University (JNU) #jnu #sps #spsjnu #materialscience #materials #materialtesting #physics #liionbattery #battery #batteries #batterytechnology #highvoltagebattery #highperformance #solvationstructure #fullbattery #highvoltageelectrolyte #liion #rechargeable #highenergydensity #fastcharging #SEI #CEI

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From this paper ( on eta carbide): "Based on the APT chemical analysis mentioned above, the C-rich regions have a carbon content of 26.8 ± 2.5 at.%. This composition is in the range of FexC type carbides (x = 2–3) which have a carbon content of 25–33.3 at.%. Based on the measured composition and the associated error bars, these carbides could be cementite (θ-Fe3C), Chi (also called Hägg) phase (χ-Fe5C2) or epsilon carbide (ε-Fe2-3C), with C contents around 25–30 at.%. However, several artifact sources can lead to a deviation in the measured composition from the actual chemical composition. " I still remain of the opinion that the aging of high carbon martensites has been correctly described by earlier Mossbauer experiments on steels and current work on spectroscopy in catalysis - expecially recent studies in Fisher Tropsch synthesis by Pasi Paalanen in his PhD thesis https://lnkd.in/ddUYPeP8 carried in the University of Utrecht deserve a common description. I am pleased to know, unfortunately just today, that my colleague prof . Dierk Raabe a worldwide expert in the field of steel and steel sustainability has recently promoted a joint group talk specifically devoted to a special mechanochemical synthesis technique possibly in the same group of researchers. Too many years ago I have been employing this technique to produce nanostructured iron carbides mixtures ( epsilon eta chi theta) that were also employed in some catalysis experiments ( CO2 hydrogenation). At the time I could also do some experiments on the thermal stability of those carbides, as the focus then was the control of their nanostructure, but Calphad in the early 90s was much less developped than it is today. Today. For a thermodynamic description, I would suggest using Calphad tools; possibly focusing more on advancing science and technology and above all interdisciplinary work than on Hirsch or other "KPI" indexes of single researchers. Yes letting closer studies on iron carbides in steels and whatsoever catalytic studies, like it was even much earlier in science and technology. I will type here the name of Lawrence John Edward Hofer, with the Nature of Carbides of Iron, in Bullettin 631of US Bureau of Mines

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Life Cycle Assessment of Hydrogen Production

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Check out my new blog post in which I delved into Direct Air Capture (DAC) of CO2. Details of DAC technologies, challenges in DAC, and work being carried out at CSIR-IICT are discussed in detail. An interesting read for those interested in climate change and sustainability. Full post - https://lnkd.in/gdDQTndV

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Slightly slower posting rate last week as I spent some time pulling together an Excel sheet that allows you to estimate the volume of electrolyte required for a given cell chemistry: https://lnkd.in/eRYtPEQq The page gives an overview of the calculation and links to the reference documents, however, you can download the excel workbook: https://lnkd.in/d5Gydr9J As a one off download it is just $15 or $25 for a yearly download pass, if you want to use it in a company we ask that you pay for the $250 corporate download pass. #batteries #electrochemistry #batterymanufacturing

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Check out our latest work in selective phosphate ion separations using electrochemical platforms in Chemical Engineering Journal. https://lnkd.in/gVgzaxnP Phosphorus discharge from agricultural runoff leads to eutrophication of water bodies. Plus, there is concern that we cannot continue to mine virgin phosphorus to meet our fertilizer demands. Devising technologies to extract phosphorus from waste streams is important for a balanced use of this valuable nutrient that sustains life. In this article, we prepared mixed matrix anion exchange membranes using highly conductive poly(phenylene alkylene) quaternary ammonium ionomers blended with manganese oxide particles. The particles have a high affinity for hydrogen phosphate anions. Coupling the composite AEM with a bipolar membrane in a capacitive deionization cell led to selective and large removal rates of phosphate from model wastewater solutions. Ab-initio simulations by my long time collaborator Prof Revati Kumar LSU Department of Chemistry determined the favorable adsorption energy for phosphate on the mixed matrix membranes over pristine membranes. Congrats to my postdoc, Bin Yang, the lead author for this work. Congrats to the other co-authors: Xiaoliu Zhang, Bharat Shrimant, Tanmay Kulkarni. Thanks to U.S. Department of Energy Office of Science, BES, Separation Science Program for funding this work! On a side note, I find phosphorus to be very interesting. My childhood friend recommended this book on phosphorus to me (link below). It is a great read. It covers the discovery of phosphorus as an element to its use in bombs, detergents, fertilizers, and its current problems in the environment. https://lnkd.in/gWjN69xM

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Comprehensive review of 130 studies shows that alkaline and PEM electrolysis performance will be negatively affected by variable power supply from wind and solar. #renewables #power #energy #wind #offshore #onshore #solar #hydropower #floating #nuclear #geothermal #efficiency #transition #susteinability #circular #economy #esg #clean #decarbonization #electrification #climate #hydrogen #mobility #greensteel #ammonia #transportation #storage #fuelcell #smartgrid #der #powersystem #generation #transmission #distribution #electricity #machines #drives #sensors #iot #education #engineering #innovation #entrepreneurship #creativity #technology #digitalization #cybersecurtity #metering

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🔬 Excited to share our latest publication in the Chemical Engineering Science Journal, co-authored by Junseok Chang and myself!! 📝 Our study unveils ChemSL, an innovative automated framework for building molecular properties using interpretable machine learning models. 🌟 With better performance and interpretability, ChemSL is poised to ease research in cheminformatics, materials science, drug discovery, and fuel design. Check out the full article in the link for insights into our approach! #ChemSL #ChemicalEngineeringScienceJournal #MachineLearning #Cheminformatics #ResearchInnovation 🚀 https://lnkd.in/gE94uhvk

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Our latest preview article published on Joule that highlights the different designs for bicarbonate electrolysis vs CO2 electrolysis: https://lnkd.in/eK8iEze6

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🗝 Computational Micromechanics is key to understand the behaviour of #compositematerials at the constituents scale. In particular, representative volume elements appear as one of the most effective tools for these analyses, as they reduce the computational cost very significantly. These RVE #finiteelementanalysis are based on periodicity to mimic the infinitely periodic surroundings. The trick to model this periodicity is the application of periodic boundary conditions (aka PBC). 🤔 How do PBCs work? PBCs set the relative displacement between periodic faces to be equal to the displacement of a master node, which can be written as: u_j - u_i = u_M u_j: displacement of node j (e.g. on left right) u_i: displacement of node i (e.g. on left face) u_M: displacement of the master node (e.g. controlling periodicity between left-right faces) For instance, with nodes i = 11, j = 51, and MN = 90, we could write: u_51 - u_11 - u_90 = 0 In #Abaqus, we can define these constraints through "equations" for every pair of periodic nodes. I like defining these in the input file through a Python script that scans the mesh and writes the equations in a blink. If you need to boost your FE simulations, you will find how to define PBC using Python in my #course "Simulation of Composite Materials with Abaqus". In the chapter on Micromechanics, we go through the whole process of generating and building a periodic RVE in 2D and 3D in full detail including cohesive interfaces as well. https://lnkd.in/etGMV_7B #mechanicalengineering #materialscience #emmc19

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I'm pleased to announce the next CorroZoom webinar by Prof. En-Hou Han, who is the leading corrosion scientist in China. CorroZoom is a free webinar series featuring presentations by world-leading corrosion scientists. Previous webinars and recordings to many of the webinars can be found here: https://lnkd.in/ecXCzWZS   "Stress Corrosion Cracking of Stainless Steels and Nickel Base Alloys" Prof. En-Hou Han Institute of Corrosion Science and Technology (ICoST) South China University of Technology (SCUT) Guangzhou, China 7 May 2024 at 0800 US Eastern Free Registration:  https://lnkd.in/e8iGxxYK Abstract Stress corrosion cracking (SCC) of different materials happens in various industries. Although SCC has long history and researchers have revealed considerable understanding, the mechanisms are not clear and accurate prediction of SCC is still not possible. Many factors affect SCC, including but not limited to alloy composition and microstructure, environment, and load (stress, strain and strain rate). This lecture will mainly discuss SCC crack initiation and propagation for Fe-Cr-Ni alloys, both stainless stainless steels and nickel-base alloys, and will especially focus on the effects of local parameters (local material, local chemical & electrochemical and local mechanical conditions). The electrochemical corrosion behavior and the chemical composition, microstructure and electronic characters of oxide films for stainless steels and Ni base alloys used in nuclear power plants will be reviewed. The effects of water chemistry and material microstructure on oxide films were analyzed in order to relate oxide film properties to electrochemical behavior. The effect of the surface after surface finishing, grinding, machining or scratching on corrosion and SCC initiation in simulated primary water of nuclear power plants will be discussed because the different manufacturing techniques can cause the formation of microstructures of different gradients near the surface and also cause large differences in surface deformation. SCC propagation in various conditions will be presented as will an SCC prediction model that has bee applied to real nuclear power industry components. Finally, future research trends on the topic will be proposed.   Biography Dr. En-Hou Han is a full professor of South China University of Technology (SCUT), President of Institute of Corrosion Science and Technology (ICoST). He received his Ph.D. from Northeastern University in Shenyang, China in 1990. He was professor at Institute of Materials Research in Shenyang from 1998-2023. Prof. Han’s research interests include (1) Localized corrosion, especially the interaction of mechanical and chemical effects, such as corrosion fatigue, SCC and hydrogen embrittlement; (2) Corrosion prevention techniques; (3) Service lifetime prediction and failure analysis by big data modelling, digital twins & AI; (4) R & D of corrosion resistant alloys.

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New comprehensive review paper on hydrogen embrittlement (June 2024). 👉 Download full paper, 50 days free access: https://lnkd.in/dKiA6eKF "Review of the hydrogen embrittlement and interactions between hydrogen and microstructural interfaces in metallic alloys: Grain boundary, twin boundary, and nano-precipitate", International Journal of Hydrogen Energy by Elsevier, Volume 72, 27 June 2024, Pages 74-109. Highlights: • The effect of the interfaces on hydrogen embrittlement (HE) of alloys is reviewed. • Hydrogen-assisted interface cracking mechanisms of alloys are summarized. • Strategies for resisting HE are proposed through the control of the interfaces. • Semi-coherent precipitates are suggested to balance strength and HE resistance. Summary: The correlation between hydrogen embrittlement (HE) susceptibility, multiple active HE mechanisms and their synergy (HELP + HEDE model), and three types of interfaces ((i) grain boundary, (ii) twin boundary, and (iii) nano-precipitate) have been comprehensively summarized and discussed. Also, strategies for HE resistance improvements are proposed in terms of the control of these microstructural interfaces in metallic alloys. Comprehensive recommendations presented in this paper give guidelines for designing and developing future precipitation-strengthened alloys with high HE resistances. Elsevier #hydrogenembrittlement #hydrogen #mechanicalengineering #engineering #corrosion #metals #energy

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Pleased to share a recent paper by the PhD student Shumeng Xie in our group, about the weak flame in hydrogen/ammonia blends at elevated conditions. Abstract: This study employs the premixed counterflow configuration and examines the potential bifurcations of the NH3/H2/air flame with one-dimensional simulations. For the first time, a novel weak combustion mode of NH3/H2 mixtures is observed and termed as the weak flame in the following. Unlike the conventional hot flame, the weak flame exhibits significantly lower flame temperatures (1300–1500 K) and a mere 1 % of the heat release rate (∼10^9 J/m3/s) associated with hot flames. Within the weak flame, H2 is entirely oxidized to H2O, whereas only a portion of NH3 is partially oxidized, resulting in the formation of H2O, N2, N2O, and NO. Further reaction path analyses reveal that the NH3 (+OH) → NH2 (+NO2) → H2NO (+NH2, +HO2, +O2, +NO2) → HNO (+O2) → NO (+HO2) → NO2 → N2O pathway is the primary oxidation route of ammonia in the weak flame. Furthermore, the effects of pressure, hydrogen content, and equivalence ratio are systematically assessed to explore the operation conditions of the ammonia/hydrogen weak flame. The study reveals that the weak flame is promoted at elevated pressures, and exists with a moderate hydrogen addition, i.e., mole fraction of 0.02–0.4. A regime diagram is further proposed to summarize the combined influences of hydrogen molar fraction and equivalence ratio. In the end, the impacts of chemical mechanisms are tested and the dominant ammonia oxidization path in the weak flame persists for models capable of predicting weak flames.

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