High Chemical Reactivity Research Articles

Application of Graphene in Water Purification

Graphene and its derivatives have emerged as promising materials for water purification due to their unique properties, including high surface area, excellent conductivity, and tunable chemical reactivity. This paper explores the application of graphene-based materials, such as graphene oxide (GO), reduced graphene oxide (rGO), and graphene composites, in various water treatment processes. The high porosity and surface chemistry of graphene make it ideal for adsorption, filtration, and removal of contaminants like heavy metals, organic pollutants, and microorganisms from water. In addition, graphene's ability to enable advanced filtration technologies such as membrane-based systems, electrochemical processes, and photo catalytic degradation offers significant improvements in water purification efficiency and selectivity. Challenges related to scalability, material functionalization, and long-term stability is also discussed. The paper highlights recent advancements in the use of graphene materials for sustainable and efficient water treatment, and provides an overview of future research directions in this field to optimize performance and commercialization. Keywords: Graphene, water treatment processes, photo catalytic, commercialization

Multi-Channel Electrical Discharge Machining of Ti-6Al-4V Enabled by Semiconductor Potential Differences

Titanium alloys are difficult to machine using conventional metal cutting methods due to their low thermal conductivity and high chemical reactivity. This study explores the new multi-channel discharge machining of Ti-6Al-4V using silicon electrodes, leveraging their internal resistivity to generate potential differences for multi-channel discharges. To investigate the underlying machining mechanism, the equivalent circuit model was developed and a theoretical simulation was carried out. Comparative experiments with silicon and conventional copper electrodes under identical parameters were also conducted to analyze discharge waveforms, material removal rate, surface quality, and heat-affected zones (HAZ). The results demonstrate that the bulk resistance of silicon is the main mechanism for generating multi-channel discharges. This process efficiently disperses the discharge energy of the single discharge pulse, resulting in smaller craters, smoother machined surfaces, and shallower recast layers and HAZ.

Structural, Electronic, and Magnetic Properties of Neutral Borometallic Molecular Wheel Clusters.

Atomic clusters exhibit properties that fall between those found for individual atoms and bulk solids. Small boron clusters exhibit planar and quasiplanar structures, which are novel materials envisioned to serve as a platform for designing nanodevices and materials with unique physical and chemical properties. Through past research advancements, experimentalists demonstrated the successful incorporation of transition metals within planar boron rings. In our study, we used first-principles calculations to examine the structure and properties of neutral boron clusters doped with transition metals, denoted as TMBn and TMB2n, where TM = Ti, Cr, Mn, Fe, Co, Nb, or Mo and n=8-10. Our calculations show that the TMB2n structures, which involve sandwiching metal atoms between two rings (called the drum configuration), and clusters with the single ring configuration, TMBn, are stable. These clusters typically have relatively large HOMO-LUMO energy gaps, suggesting high kinetic stability and low chemical reactivity. Moreover, the clusters display interesting magnetic properties, determined not only by the metal atoms but also by the induced magnetism of the boron rings. These structures have potential applications in spintronics and sensing. This work also provides a basis for studying magnetism in the one-dimensional limit.

Validation of a laboratory spray generation system and its use in a comparative study of hexamethylene diisocyanate (HDI) evaluation methods.

Isocyanates are well-known irritants and sensitizers, and measuring their occupational airborne exposure is challenging due to their high chemical reactivity and semi-volatile nature. This study builds on a previous publication by our team that focused on comparing evaluation methods for isocyanates. The current research aims at developing, validating, and applying a laboratory generation system designed to replicate real-world conditions for spraying clear coats in autobody shops using hexamethylene diisocyanate (HDI)-based products. The system involved a spray gun connected to two chambers in series, enabling sample collection and analysis. The system successfully generated HDI and isocyanurate concentrations ranging from 0.008 to 0.040 mg m-3 and 0.351 to 3.45 mg m-3, respectively, with spatial homogeneity (RSD) of 5.8% and 16.5%. The particle-size distribution (MMAD) of 4 μm was measured using a cascade impactor and an electrical low-pressure impactor. The samples generated were used to correlate the amount of isocyanates collected with scanning electron microscope images of droplets on a filter. Three methods were compared to the reference method-an impinger with a backup glass fibre filter (GFF) and 1,2-methoxyphenylpiperazine (MP) based on ISO 16702/MDHS 25-in six generation experiments: (1) Swinnex cassette 13 mm GFF MP (MP-Swin); (2) closed-face cassette 37 mm GFF (end filter and inner walls) MP (MP-37); and (3) denuder and GFF dibutylamine (DBA) (ISO 17334-1 Asset). The analysis revealed clear trends regarding which sampler sections collected HDI (mainly in the vapor phase) or isocyanurate (exclusively in the particulate phase). The study found no significant bias between the tested methods (MP-Swin, MP-37, and Asset) and the reference method (impinger) for both HDI monomer and isocyanurate. The three tested methods showed limits of agreement beyond the acceptable range of ±30% (95% confidence interval), largely due to data variability, though MP-Swin and MP-37 exhibited lower variability than Asset. The results will be further evaluated in a real-world environment where similar clear coats are used.

Short Review on Plasma–Aerosol Interactions

ABSTRACTSystems where cold atmospheric plasma interacts with liquid aerosols provide information on unexplored physico‐chemical phenomena and yield multiple advantages. Plasma‐activated aerosols show high chemical reactivity within small liquid microdroplet volumes, making them suitable for various applications and industrial processes. Plasma–aerosol interactions present complex interdisciplinary challenges that demand detailed investigations of the underlying physical, chemical, and transport mechanisms. This short review focuses on the key challenges in understanding plasma–aerosol interactions and the diagnostic hurdles in elucidating the physical and chemical mechanisms governing microdroplet interactions with plasma discharges. The scalability of plasma–aerosol systems, including high‐throughput charged water flows, are analyzed. Some “niche” applications of plasma–aerosols are identified, especially in decontamination, nitrogen fixation, and agriculture. The controversies in the field are also introduced and critically discussed. The review concludes with a proposed path and outlook for the development of plasma–aerosol technology.

Laser Surface Texturing of Cutting Tools for Improving the Machining of Ti6Al4V: A Review

The machining of titanium alloys, particularly Ti6Al4V, presents a significant challenge in manufacturing engineering. Its high strength, low thermal conductivity and high chemical reactivity make Ti6Al4V a hard-to-machine material. However, the machining process is critical for aerospace and biomedical industries. The rapid wear and short lifetime of cutting tools are the main limitations in Ti6Al4V machining, leading to a large increase in manufacturing costs and compromising the surface quality of machined components. Faced with this problem, the texturing of cutting tools, especially through laser-based techniques, has gained considerable attention in the last decade due to improvement of the tribological properties of textured surfaces. Laser Surface Texturing (LST) has emerged as a promising technique to improve the tribological performance of cutting tools by enabling the creation of precise surface structures. Building on prior research, this review provides a comprehensive overview of the most recent research on this topic, summarizing key findings and outcomes from various investigations.

Internal Curing Effects of Slag on Properties and Microstructure of Ambient-Cured Fly Ash-Based Geopolymer Mortar

The preparation of ambient-cured fly ash-based geopolymer mortar (FAGM) with high strength by utilizing the high chemical reactivity of slag is key to realizing the sustainable and efficient application of solid waste resources. This paper investigates the influence of different type S95 slag contents (0%, 5%, 10%, 15%, 20%, 25%, and 30%) on the fluidity, setting time, and mechanical properties of FAGM at ambient temperature. The direct method is first adapted to monitor the influence of slag on geopolymerization. The results indicate that slag has a minimal effect on the fluidity of the mortar, while the setting time decreases and compressive strength increases with higher slag content. For FAGM with 30% slag content, the setting time is reduced from 3160 min to 140 min, with a decrease of 95.6%, and a 3-day and 28-day compressive strength increase from 1.5 MPa and 34.7 MPa to 33.5 MPa and 73.4 MPa, with enhancements of 2170.2% and 110.3%, respectively. Slag also exerts an internal curing effect, raising the internal curing temperature and accelerating the geopolymerization process of fly ash, thereby improving the compactness of FAGM and reducing its porosity. This approach successfully enables the production of high-strength, ambient-cured FAGM.

Characterization of Sodium Thermal Insulation Reaction Product and its Effect on Fatigue Crack Growth in 316 LN Austenitic Steel

Though sodium is the most preferred coolant for fast breeder reactors due to excellent heat transfer capabilities, its high chemical reactivity poses a concern during accidental leaks. Despite defense in depth in various levels for protecting the sodium leaks in the heat transport circuits, small undetected leaks may lead to localized degradation of structural material due to deposition of reaction products in the leak zone. Experiments have been conducted by exposing SS-316 LN specimens to sodium–glass wool interaction zone at 300 °C in air to study the influence of reaction products on chemical composition and crack growth properties. Post-exposure X-ray diffraction analysis of the samples revealed presence of silicates and aluminates of sodium in the outer layers, and complex ternary and quaternary oxides of sodium, iron, chromium and nickel in the inner layers. Scanning electron microscopy analysis revealed deposition of oxides on the exposed surface. Elemental analysis of the samples carried out by energy-dispersive spectroscopy indicated leaching of major alloying elements like chromium, nickel and iron to a depth of about ~ 25 µm from the exposed surface. Room-temperature fatigue crack growth studies on the exposed specimen shown considerable reduction in crack initiation (threshold) fracture toughness range ΔKth.

Highly Stable Near-Infrared II Luminescent Diradicaloids for Cancer Phototheranostics.

Near-infrared II (NIR-II) phototheranostic agents have become prominent agents for the early diagnosis and precise treatment of cancer. Organic open-shell diradicaloids with distinct structure and narrow band gap are promising candidates for phototherapeutic agents due to their strong spin-coupling effect and NIR light-harvesting capacity. However, achieving stable and efficient NIR-II luminescent diradicaloids is crucial yet rather challenging considering their high chemical reactivity and self-absorption. Herein, two highly stable NIR-II luminescent diradicaloids, 2PhNVDPP and PhNVDPP, were successfully fabricated by employing an acceptor planarization/π-conjugation extension and donor rotation strategy. After encapsulation into water-dispersible nanoparticles (NPs), 2PhNVDPP NPs exhibit NIR-II luminescence, high PCE of 53%, and improved photo/heat stability. In vivo experiments with 2PhNVDPP NPs demonstrated the clear visualization of blood vessels and tumors, as well as the successful NIR-II imaging-guided photothermal ablation of tumors. This study not only develops a pioneering stable diradicaloid phototherapeutic agent with NIR-II luminescence but also provides a unique perspective for the effectiveness of multimodal anticancer therapy.

Theoretical and Experimental Insights into Dendrite Growth in Lithium‐Metal Electrode

AbstractA stable lithium‐metal electrode can enable the shift from the Li‐ion batteries to the next generation chemistries such as Li−S and Li−O2 with significant gains in the energy density and sustainability. This transition, however, is hindered by the dendrite formation, high chemical reactivity, and volume changes of the Li electrode. Although recent advancements in computational and experimental research have deepened our understanding of these issues, the primary obstacles to the commercialization of the lithium‐metal batteries (LMBs) still persist. To address these challenges, a synergistic approach that combines computational and experimental strategies shows great promise. In this regard, this paper reviews the current experimental and theoretical understanding of the lithium‐metal electrodes in view of the initiation and growth mechanisms of the lithium dendrites and interface instability. Leveraging the strengths of both approaches can offer a holistic insight into the LMB performance and guide the development of innovative designs for electrolytes and electrodes that can enhance the stability and performance of the LMBs.

An Mn-Enriched Interfacial Layer for Reversible Aqueous Mn Metal Batteries.

Aqueous manganese metal batteries have emerged as promising candidates for stationary storage due to their natural abundance, safety, and high energy density. However, the high chemical reactivity and sluggish migration kinetics of the Mn metal anode induce a severe hydrogen evolution reaction (HER) and dendrite formation, respectively. The situation deteriorates in the low-concentration electrolyte especially. Here, we propose a novel approach to construct an Mn-enriched interfacial layer (Mn@MIL) on the Mn metal anode surface to address these challenges simultaneously. The Mn@MIL acts as a physical barrier to not only suppress HER but also accelerate the Mn2+ diffusion kinetics through the Mn2+ saturated interfacial layer to inhibit dendrite growth. Therefore, in the low-concentration electrolyte (1 M MnCl2), the Mn||Mn symmetric cells and Mn||V2O5 full cells with high mass loading demonstrate promising cycling stability with minimal polarization and parasitic reactions, making them more suitable for practical applications in a smart grid.

High‐entropy (Ho1/4Er1/4Dy1/4Gd1/4)2Si2O7: A promising thermal environmental barrier coating material

AbstractThis work presents the exploration of a promising thermal environmental barrier coating material by engineering the compositions of (Ho1/4Er1/4Dy1/4X1/4)2Si2O7 high‐entropy rare‐earth disilicates (HERED‐X, X = Gd, Tm, Yb, Lu, Sc, Y). Among all the samples, the as‐fabricated HERED‐Gd samples possess the best CMAS corrosion resistance with a corrosion rate of 8.2 ± 0.14 µm h−1 at 1673 K, which is attributed to the synergistic effects of high chemical reactivity of HERED‐Gd and good stability of the formed apatite in CMAS melt. Moreover, they demonstrate a matched coefficient of thermal expansion (4.6 × 10−6 K−1) with SiCf/SiC composites (4.5–5.5 × 10−6 K−1) and a low thermal conductivity (1.89 W m−1 K−1 at room temperature).

Super SEI-Forming Anion for Enhanced Interfacial Stability in Solid-State Lithium Metal Batteries.

The extremely high chemical reactivity of lithium metal (Li°) electrodes and its enormous volume change during repetitive cycles cause continuous interfacial degradations in prevailing organic electrolytes, thus deteriorating the cycling performances of rechargeable lithium metal batteries (LMBs). Herein, departing from traditional wisdom on the design of electrolyte components, a super SEI-forming anion (SSA), as an efficient percussor for building stable interphases on Li° electrode, is proposed. Comprehensive investigations related to the unique anion chemistry of SSA reveal that the sulfonate and polyfluoroalkyl functionalities synergistically contribute to uniform spatial distributions of designer interfacial species, greatly improving the surface coverage property and conformal ability of the resulting interphases. Consequently, the incorporation of SSA leads to significant improvements in the cyclability of Li° electrode (exceeding 575 mAh cm-2 before failure) and the corresponding rechargeable Li°||LiFePO4 cells [a five-time increase in lifespan as compared to the benchmark cell with the popular SEI-forming anion bis(fluorosulfonyl)imide (FSI)]. The present work offers a paradigm shift to tame the notorious interfacial issues via upgraded anion chemistry, which can promote the practical development of rechargeable LMBs and other kinds of metal batteries.

Synthesis, Crystal Structure and Antifungal Activity of (E)-1-(4-Methylbenzylidene)-4-(3-Isopropylphenyl) Thiosemicarbazone: Quantum Chemical and Experimental Studies.

A novel (E)-1-(4-methylbenzylidene)-4-(3-isopropylphenyl) thiosemicarbazone was synthesized in a one-pot four-step synthetic route. Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonances (NMR), single-crystal X-ray diffraction, and UV-visible absorption spectroscopy were utilized to confirm the successful preparation of the title compound. Single-crystal data indicated that the intramolecular hydrogen bond N(3)-H(3)···N(1) and intermolecular hydrogen bond N(2)-H(2)···S(1) (1 - x, 1 - y, 1 - z) existed in the crystal structure and packing of the title compound. Besides the covalent interaction, the non-covalent weak intramolecular hydrogen bond N(3)-H(3)···N(1) discussed by atoms in molecules (AIM) theory also functioned in maintaining the title compound's crystal structure. The strong intermolecular hydrogen bond N(2)-H(2)···S(1) (1 - x, 1 - y, 1 - z) discussed by Hirshfeld surface analysis played a major role in maintaining the title compound's crystal packing. The local maximum and minimum electrostatic potential of the title compound was predicted by electrostatic potential (ESP) analysis. The UV-visible spectra and HOMO-LUMO analysis revealed that the title compound has a low ΔEHOMO-LUMO energy gap (3.86 eV), which implied its high chemical reactivity due to the easy occurrence of charge transfer interactions within the molecule. Molecular docking and in vitro antifungal assays evidenced that its antifungal activity is comparable to the reported pyrimethanil, indicating its usage as a potential candidate for future antifungal drugs.

Experimental and theoretical computational study of corrosion inhibitors in the cobalt bulk chemical mechanical polishing (CMP) process

Cobalt is a potential substitute for copper as local interconnects in sub-10 nm interconnects, the chemical mechanical polishing (CMP) of which is quite challenging due to the high chemical reactivity of Co. By using a combination of experiments and theoretical calculations, the optimum corrosion inhibitor of Co is identified and the corrosion inhibition mechanism of TTLYK on Co is further investigated. It investigates the effects of various corrosion inhibitors, including potassium oleate, dodecyl benzene sulphonic acid, octyl hydroxamic acid, and 2,2′-[[(methyl-1H-benzotriazol-1yl) methyl] imino] bis-ethanol (TTLYK) on Co through chemical mechanical polishing and static etching experiments. The results show that among various corrosion inhibitors, TTLYK presents the best corrosion inhibition effect. When the basic slurry contains 10 mM TTLYK, the corrosion inhibition efficiency could reach 96.23 %, the material removal rates of Co is 161.79 nm/min, the static etching rates is 0.85 nm/min, and the material removal selectivity ratio of Co and Ti is 39:1. The results fully meet the requirements of the Co bulk CMP process. It is revealed TTLYK could form a protective layer with a synergistic physical and chemical adsorption on Co, in which the chemical adsorption occurs through the formation of CoN bonds. The adsorption of TTLYK could decelerate the transformation of CoO and Co(OH)2 to Co3O4, and the as formed Co-TTLYK complex provides the main corrosion inhibition.

Hydrogen Evolution Atomic Cluster Catalysts-Decorated Hierarchical Nanoporous Zinc for on-Demand Hydrogen Generation By Metal Hydrolysis

In recent years, there has been an increasing interest in nanoporous metals due to their wide range of applications, including catalysis, electrocatalysis, energy storage, actuation, and plasmonics. However, considerable attention has been given to precious nanoporous metals such as nanoporous Au, Pd, Pt, Ag, and Cu due to their low chemical reactivity, which makes them relatively easy to synthesize and characterize. Less precious nanoporous metals such as nanoporous Zn, Al, and Mg have been rarely fabricated and characterized because of their relatively high chemical reactivity 1. In this talk, I will present a novel, highly scalable approach to making hierarchical nanoporous zinc (NP-Zn) decorated with atomic clusters of hydrogen evolution catalysts for on-demand hydrogen generation by metal hydrolysis. Our approach involves selective etching in combination with galvanic replacement reactions. The conventional selective etching method requires several days to create a monolithic piece of NP-Zn 2. Our approach creates the same amount of hierarchical NP-Zn in less than 5 minutes, instead of several days. In our work, we used focused ion beam/scanning electron microscopy techniques to reveal the internal nanoscale morphology of the hierarchical NP-Zn, and small-angle X-ray scattering to analyze the pore size distribution. In general, when NP-Zn is used for hydrogen generation by metal hydrolysis, the hydrogen generation yield is low, typically around 20%. This is because zinc is naturally a poor hydrogen evolution material. Our process overcomes this issue by creating NP-Zn with its interface decorated with clusters of hydrogen evolution catalysts, which enables hydrogen generation yield exceeding 90% depending on the catalyst loading. References (1) Fu, J.; Welborn, S. S.; Detsi, E. Dealloyed Air- and Water-Sensitive Nanoporous Metals and Metalloids for Emerging Energy Applications. ACS Appl. Energy Mater. 2022, 5 (6), 6516–6544. https://doi.org/10.1021/acsaem.2c00405.(2) Fu, J.; Deng, Z.; Lee, T.; Corsi, J. S.; Wang, Z.; Zhang, D.; Detsi, E. pH-Controlled Dealloying Route to Hierarchical Bulk Nanoporous Zn Derived from Metastable Alloy for Hydrogen Generation by Hydrolysis of Zn in Neutral Water. ACS Appl. Energy Mater. 2018, 1 (7), 3198–3205. https://doi.org/10.1021/acsaem.8b00419.

Nonenzymatic Sequestering of Formaldehyde into the Antibiotic Methylene-Bridged Dimer Phaeochromycin F by Streptomyces sp. OUCMDZ-4982 as a Possible Multipronged Chemical Defense Mechanism.

Metabolites with high chemical reactivity serve important roles in chemical defenses of organisms. Formaldehyde, as a simple and highly reactive small molecule, can be produced by microorganisms, plants, and animals. Its toxicity is well known, but information about its other biological functions remains scarce. Here, we report that the natural product SEK34b produced by Streptomyces species can react nonenzymatically with formaldehyde in water to yield the methylene-bridged dimer phaeochromycin F. This process can eliminate the toxic substance formaldehyde produced by Staphylococcus aureus. Furthermore, there is a substantial inhibitory impact of phaeochromycin F on S. aureus. We hypothesize that these constitute an integrated system of defense and attack of Streptomyces species against competitors. Our study indicates that formaldehyde can react with vancomycin and tigecycline under mild conditions to generate the derivatives bearing an imidazolidin-4-one moiety, thereby reducing the antibacterial activity of these antibiotics. These data provide a possible chemical interaction mechanism of bacteria involving the nonenzymatic reactions of formaldehyde with highly reactive natural products.

Effects of sodium ions on the tribological and antioxidation properties of borates

A borate ester (BMBS) and its sodium salts (BMBSNa) were synthesized and used as multifunctional lubricant additives in oleic acid. Results showed that BMBSNa possessed better anti-oxidation and tribological properties than BMBS. Worn surfaces analysis revealed that BMBSNa was more favorable to forming boundary film containing h-BN and FeS. Theoretical calculation suggested that BMBSNa had a higher chemical reactivity and better metal adsorption ability than BMBS. Fukui indices showed that sodium ions favor free radical reaction. Radial distribution functions (RDF) indicated that sodium ions help the adsorption of BMBSNa on the iron surface. It can be concluded that sodium ions benefit the oxidation resistance of base oil, and contribute to forming good boundary lubrication film to achieve good tribological properties.

Fabrication of three-dimensional bicontinuous porous aluminum by vapor phase dealloying

The development of lightweight, high-specific-surface-area, and exceptionally tough porous aluminum (Al) through dealloying has been consistently captured the attention of the porous metal field. However, widely employed dealloying approaches such as electrochemical dealloying (ECD) and liquid metal dealloying (LMD) face limitations in constructing porous metals with high chemical reactivities. In this study, we employed an emerging vapor phase dealloying (VPD) method, utilizing the differences in saturated vapor pressures among alloy constituents to selectively remove elements with high vapor pressures under optimized temperature and vacuum conditions. The VPD process, characterized by its chemical-free nature and the application of high temperatures, rapidly produces porous Al with varying ligament sizes from the MgZnAl system. The resulting porous Al, distinguished by its crack-free structure and substantial ligament size, exhibits remarkable toughness. The successful fabrication of porous Al using the VPD method effectively bridges the existing gap in generating porous metals with low melting points and high chemical reactivity through ECD and LMD methods. This advancement holds significance for broadening the range of systems and application fields for porous metals.

Bilayer diatomite-based composite coatings with superhydrophobic and self-healing properties for enhanced anticorrosion of AZ31B magnesium alloys

Magnesium (Mg) alloys have shown great promise as engineering materials due to their unique properties. However, their high chemical reactivity limits their wide application. Herein, a novel bilayer diatomite-based composite coating was fabricated by spraying coating AZ31B Mg alloy with a bottom layer of benzotriazole (BTA)-loaded diatomite/epoxy resin for providing self-healing properties and a top layer of hexadecyltrimethoxysilane (HDTMS)-modified diatomite/epoxy resin for contributing superhydrophobic properties. The resulting bilayer composite coating (BTA@DME-12 %) exhibited exceptional stability and maintained its superhydrophobicity in a temperature range of 0–160 °C. The coating also delivered good adhesion and physical stability in tape-peeling and frictional testing. Electrochemical study results demonstrated that the BTA@DME-12 % coating exhibited lower corrosion tendencies and corrosion rates compared to the BTA@DME-free coatings. After immersing in 3.5 wt% NaCl solution for 21 days, the bilayer composite coating still achieved an impressive anti-corrosion efficiency of 99.6 %. This work not only provides a scalable and simple method to prepare self-healing and superhydrophobic bifunctional coatings for corrosion protection of Mg alloy, but also presents a novel multifunctional coating strategy by utilizing diatomite with a hierarchical structure.