Initial Oxidation Research Articles (Page 1)

Electrochromic materials have recently aroused extreme attention due to their exceptional application potential in display screens, architectural glass, and coating stealth materials, etc. Developing electrochromic polymers synchronously sharing blue and second near-infrared (NIR-II) transmissive is urgently in demand but extremely scarce. Herein, three kinds of electrochromic polymers featuring redox electrochemical and electrochromic properties are obtained through electrochemical polymerization of three monomers, ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA, which are constructed based on 3,4-ethylenedioxythiophene (ProDOT) and triphenylamine (TPA) derivatives. Electrochemical studies reveal that ProDOT-TPA exhibits low initial oxidation potential of 0.59 V, possessing significant advantages for obtaining high-quality polymers. The optimized polymers [P(ProDOT-TPA)] show significant properties in electrochromic devices with optical contrast of 14.38% at 400 nm and 49.55% at 1100 nm, along with coloration efficiency of 123 cm2 C-1 and response times of 0.5 s.

Oxidizing transition metal surfaces are generally characterized by an increasing heterogeneity at simultaneous lowering of crystalline order. This complexity eludes present-day first-principles descriptions, with predictive-quality surface phase diagrams commonly derived from comparing the stability of a small number of ordered surface structural models that are motivated by partial experimental characterization or chemical intuition. Here the computational acceleration brought by machine-learned interatomic potentials is leveraged for a systematic sampling of the configurational phase space through replica exchange molecular dynamics. Thermodynamic averaging subsequently yields grand-canonical expectation values for observables like O coverage that account for the disorder and diversity of the sampled structures. Application to the initial oxidation of the Cu(111) surface reveals the (purely entropic) stabilization of sparse O adsorbates at the onset, a plethora of energetically essentially degenerate polymeric -O-Cu-O- ring and chain networks at higher O loading, as well as the presence of experimentally discussed minority species. The in silico surface phase diagram correspondingly shows marked differences to one based merely on established ordered surfacereconstructions.

As a conceptual study for low-energy hydrogen production, potentially coupled with off-grid photovoltaics, this work focuses on overcoming the constraint of the oxygen evolution reaction (OER), which features a high anode potential and significant overpotential. To reduce energy consumption, the Fe2+ oxidation reaction is employed to replace OER, coupled with Fe2+ regeneration using natural biomass. Experimental results reveal that Fe2+ oxidation reaction is an effective substitute, with an initial oxidation potential of 0.5 V (vs. Hg/Hg2SO4), much lower than that of OER. Fe2+ regeneration is notably influenced by both biomass type and reaction temperature. Chlorella pyrenoidosa (CP) achieves the highest Fe3+ reduction rate of 90.5% at 190 °C. Water-soluble organic compounds generated during biomass oxidation exert a negative impact on Fe2+ electrooxidation by accumulating on or coating the electrode surface, and the compounds derived from CP exert a less detrimental effect. Moreover, enhancing magnetic stirring, elevating temperature, and selecting an appropriate anode material can significantly boost the oxidation reaction. Under optimized conditions, the current density during electrolysis of CP filtrate at 1.1 V reaches 280 mA/cm2, much higher than values reported in similar studies. This highlights the great potential of this co-electrolysis approach for efficient hydrogen production driven by off-grid photovoltaic power.

The formation of atomically flat Si(111)–H surfaces was critical for molecular electronics, nanoscale device fabrication, and surface chemistry studies. We systematically investigated how initial oxide composition and dissolved oxygen affected terrace-formation kinetics during ammonium fluoride (NH4F) etching. N-type Si(111) was cleaned with either oxygen plasma or piranha solution to generate, respectively, a more uniform versus a chemically heterogeneous oxide, and then etched in NH4F containing 0–5% (w/v) ammonium sulfite (AS) as an oxygen scavenger. AFM acquired every 2 min over 20 min revealed that plasma-pretreated surfaces reached atomically flat terraces earlier and more reproducibly than piranha-pretreated surfaces. Increasing AS concentration suppressed oxygen-induced etch pits and promoted the earlier appearance of large, well-ordered terraces, whereas prolonged etching led to roughening. XPS and ATR-FTIR corroborated differences in the starting oxides and confirmed post-etch H-termination. Collectively, the results indicated that oxide uniformity together with oxygen scavenging correlated with faster attainment and greater persistence of low-roughness terraces, providing a practical framework for reproducibly preparing hydrogen-terminated Si(111)–H surfaces.

Spectroelectrochemical studies of TDMQ20: A potential drug against Alzheimer's disease - part 2 - Cu-complexes.

Direct mechanocatalysis has arisen as a promising tool to achieve synthetic transformations by utilizing reaction vessels and/or media made of a material capable of acting as a source of catalysis. One common metal utilized for this purpose is copper, the surface of which is not a static environment but rather undergoes many transformations (particularly upon exposure to water and oxygen). Here we have utilized in-house developed equipment for work under controlled atmosphere milling, including a composite milling jar design that enables investigating the behaviour of the copper surface in either impact- or shear-dominated milling regimes. We exploit the unique sensitivity to Cu(ii) species of the mechanocatalytic coupling of isocyanate and sulfonamide to form the sulfonylurea diabetic drug tolbutamide to establish methods to control the copper surface composition and reveal the factors that influence copper transformation into different states during milling. We reveal the active catalyst formed through direct mechanocatalysis to be a hydroxylated copper species and demonstrate that the reaction proceeds via surface wear and subsequent catalyst formation. Any initial surface oxide is observed to be insignificant to the overall process. The use of the composite reaction jar further revealed that wear dominates from the end regions of the vessel, undergoing primarily impact forces. Based on these finding and density functional theory (DFT) calculations, we present a reaction mechanism which explains the different yields of in situ generated Cu(OH)2 and a traditional CuCl2 pre-catalyst. These results highlight the importance of systematic investigations of surface characteristics for understanding and controlling direct mechanocatalysis and demonstrate methods to realize these goals.

Enhancement of soil DOC and electron transport by biochar strengthens Cd immobilization via iron oxides transformations in waterlogged soils.

Mixing of zeolite facilitates re-sequestration of heavy metals via generated Fe-(oxyhydr)oxides in sediments in the presence of NO3- compared to capping.

Manipulating electrochemical phosphate recovery from acidic wastewater for synthesizing LiFePO4/C cathode material.

In this study, glucose is used as the source of C; through cathode plasma electrolytic deposition technology, a carbon nano coating is prepared on the surface of carbon fiber. The carbon coating is analyzed using scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy to investigate the effect of pH on the microstructure of the carbon coating on the surface of carbon fiber. At the same time, the oxidation resistance of the coating and the changes in the tensile properties of carbon fiber after high-temperature heat treatment were also investigated. The results showed that reducing the pH value can improve the microstructure of the carbon coating, and the best performance of the carbon coating sample was obtained at pH = 3. The initial oxidation temperature and oxidation termination temperature increased by 156 °C and 110 °C, respectively, compared to the treated carbon fiber but without coating, and the tensile property remains a high value (2740 MPa) after high-temperature heat treatment.

Exploring the initial oxidation of the N-Mo co-doped layer on uranium surface by XPS

Influence of precipitates on the initial oxidation behavior of GH4169 superalloy at 1000 °C

Sodium-ion batteries (SIBs) have emerged as promising energy storage solutions due to resource abundance and low cost, yet their practical deployment is hindered by limited operating voltages of cathode materials. Herein, we propose a universal ligand-field engineering strategy to enhance voltage through electronic structure modulation in transition metal oxides. Using the Na0.67Mg0.2Mn0.8O2 as a model system, weak-field ligands are introduced to alter the coordination environment of MnO6 octahedra. Experimental and theoretical results demonstrate the weak-field ligands reduce Mn octahedral splitting energy, inducing a downshift of the orbital. This shifts the valence band maximum away from the vacuum level, thereby elevating the Mn3+/Mn4+ redox potential with an average voltage increase of 0.24V. Concurrently, the lowered initial Mn oxidation state induces an increased discharge capacity by 35.7% (153.2mA h g-1), while suppressing Jahn-Teller distortions and Mn3+ disproportionation yielding 94.4% capacity retention after 200 cycles (versus 69.9% in pristine sample). This ligand-engineering strategy in regulating redox voltage can be extended to other systems with -involved redox systems (such as Ni-, Fe-, and Mn-based cathodes). Our work establishes a direct correlation between orbital energy modulation and operating voltage, providing foundational insights for designing Na-layered oxide cathodes with high operating voltage.

Abstract Sodium‐ion batteries (SIBs) have emerged as promising energy storage solutions due to resource abundance and low cost, yet their practical deployment is hindered by limited operating voltages of cathode materials. Herein, we propose a universal ligand‐field engineering strategy to enhance voltage through electronic structure modulation in transition metal oxides. Using the Na0.67Mg0.2Mn0.8O2 as a model system, weak‐field ligands are introduced to alter the coordination environment of MnO6 octahedra. Experimental and theoretical results demonstrate the weak‐field ligands reduce Mn octahedral splitting energy, inducing a downshift of the orbital. This shifts the valence band maximum away from the vacuum level, thereby elevating the Mn3+/Mn4+ redox potential with an average voltage increase of 0.24 V. Concurrently, the lowered initial Mn oxidation state induces an increased discharge capacity by 35.7% (153.2 mA h g−1), while suppressing Jahn–Teller distortions and Mn3+ disproportionation yielding 94.4% capacity retention after 200 cycles (versus 69.9% in pristine sample). This ligand‐engineering strategy in regulating redox voltage can be extended to other systems with ‐involved redox systems (such as Ni‐, Fe‐, and Mn‐based cathodes). Our work establishes a direct correlation between orbital energy modulation and operating voltage, providing foundational insights for designing Na‐layered oxide cathodes with high operating voltage.

The carboxylato-prism[6]arene acts as an efficient catalyst for the oxidation of aromatic amines in water, utilizing hydrogen peroxide (H2O2) as a green oxidant. The findings indicate that forming supramolecular endo-cavity complexes between aniline derivatives and the prism[6]arene is essential for catalytic activity. Calorimetric investigations demonstrate that this complex formation is primarily driven by entropic factors associated with expulsing frustrated water molecules from the deep hydrophobic cavity of the prism[6]arene. In silico studies further confirm the presence of these water molecules within the cavity and their subsequent release upon the introduction of aromatic amines. Additionally, a computational approach was employed to elucidate the initial oxidation steps of aniline within the prism[6]arene cavity. This encapsulation process significantly lowers the activation free energy by 34.94 kJ mol-1, thereby enhancing reactivity through hydrogen bonding and solvent effects. The computational results closely align with experimental data, underscoring the critical role of host-guest interactions within the deep cavity of the prism[6]arene in facilitating the oxidation process.

BackgroundUreibacillus massiliensis (U. massiliensis), a Gram-positive bacterium belonging to the phylum Bacillota, has undergone two significant taxonomic revisions before being classified under the Ureibacillus. Although previous studies have highlighted its promising applications in industrial production and environmental remediation, the lack of genomic information has limited the research on its functional mechanisms and industrial development.ResultThis study successfully isolated and identified a novel strain of U. massiliensis through whole-genome sequencing, constructing a complete genomic map of the species. Orthologous gene cluster (OGs) analysis and genetic recombination analysis revealed the phylogenetic position of the newly isolated strain B05, highlighting deficiencies in the current classification of Lysinibacillus and Ureibacillus, as well as the limitations of traditional taxonomic approaches that rely on single phenotypic or genic characteristics. These findings provide new molecular insights into the accurate delineation of these two genera. In terms of pathogenicity, the isolated strain harbors 239 virulence factors, primarily associated with gastric and brain infections, along with four major antibiotic resistance genes involved in resistance to teicoplanin and vancomycin. Functional annotation revealed that the strain predominantly carries genes related to carbohydrate enzyme activity, with over 50% being glycosyl transferase genes. A significant number of genes are also involved in critical processes such as amino acid transport and metabolism, and transcription, while very few are associated with chromatin structure, dynamics, or the cytoskeleton. Additionally, we found that the strain possesses robust metabolic capabilities for carbohydrate compounds, including the ability to convert ginsenoside Rb1 into Rd, showcasing its potential applications in biotransformation. In terms of microplastic degradation, U. massiliensis can accelerate the degradation process by producing specific P450 enzymes that assist in the further metabolism of initial oxidation products. It may also synergize with other microorganisms to enhance overall degradation efficiency.ConclusionThis study successfully isolated and identified a novel strain of U. massiliensis through whole-genome sequencing, constructing a complete genomic map of the species and clarifying its phylogenetic position. Based on functional annotation and virulence factor prediction, the study further delineated the potential functions of the strain, comprehensively evaluating its potential pathogenic risks as well as its application value in biotransformation and microplastic degradation. These findings lay a foundation for the further development of microbial resources and provide new insights for the production and application of U. massiliensis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12866-025-04225-8.

ABSTRACTThe surface ageing of silicone rubber composite insulators, widely used in power systems, poses significant challenges. This study integrates Fourier transform infrared (FTIR) spectroscopy with machine learning to evaluate ageing states and explore underlying mechanisms under various environmental conditions. A dataset covering light, medium, and severe ageing was built through FTIR experiments, spectral feature extraction, and data augmentation. An ensemble learning model achieved a classification accuracy of 95.42%. SHapley Additive exPlanations (SHAP) analysis indicated that silicon–oxygen backbones, silylmethyl groups, and hydroxyl groups are key to the ageing process. The silicon–oxygen backbone is dominant in initial oxidation and cross‐linking, whereas silylmethyl group reactions occur later. Hydroxyl group changes are complex and strongly environment‐dependent during severe ageing. The model was also applied to naturally aged samples from Tibet and Inner Mongolia, showing strong classification performance and revealing clear regional differences. These findings are valuable for assessing surface ageing, analysing ageing mechanisms and developing grading standards for composite insulators.

ABSTRACTThe overwhelming amount of plastic produced is an unprecedented challenge for humanity due to the lack of end‐of‐life solutions for heterogeneous plastic wastes. One possibility is feedstock recycling of mixed plastics and complex polymers with subsequent biological funnelling and upcycling. Major depolymerisation products of common plastics such as polyurethanes, polyesters and polyamides include aliphatic dicarboxylic acids or diols such as adipic acid (AA) and 1,4‐butanediol (BDO), which can be metabolised by engineered Pseudomonas putida strains. However, the spectrum of upcycled compounds that can be produced from these monomers is still limited. Therefore, we extended the substrate spectrum of an aromatics‐overproducing Pseudomonas taiwanensis strain to AA and BDO. Adaptive laboratory evolution (ALE) followed by genome sequencing was used to identify and reverse engineer key growth‐enabling mutations. In this context, we observed a conflict between the dual objectives of fast growth on AA and efficient aromatics production, which materialised in the form of mutations in the ribosomal protein‐encoding gene rpmE. These mutations promote faster growth on AA at the cost of aromatics production. In contrast to P. putida KT2440, knockout of the repressor gene psrA regulating expression of genes involved in β‐oxidation had no positive effect on growth of P. taiwanensis on AA. Evolution for growth on BDO revealed several point mutations that affect expression of multiple oxidoreductases, with an identified key role for the dehydrogenase encoded by PVLB_10545. This dehydrogenase likely catalyses the initial oxidation of BDO, thus substituting for PedE, which is present in P. putida but absent in P. taiwanensis. Integration of RpcTAL into the Tn7 site enabled de novo production of 4‐coumarate with a yield of 14.4% ± 0.1% (Cmol/Cmol) from BDO and 11.5% ± 0.3% (Cmol/Cmol) from AA. Thereby, the potential of these P. taiwanensis strains for upcycling plastic hydrolysates to value‐added compounds was successfully demonstrated.

Microscopic insights into the initial oxidation process of single crystalline platinum group metal surfaces: From subsurface oxygen, a ghost species, towards surface oxide

High pure synthetic waxes are valuable both for the separation of narrower fuel fractions by hydrorefining and for various industries, such as pharmaceuticals, cosmetics, as well as the production of thermoplastic adhesives and various polymer compositions. The work studied the possibility of obtaining high molecular weight hydrocarbons via Fischer–Tropsch synthesis in a fixed bed reactor in the presence of cobalt catalyst. The studied catalysts were synthesized on the basis of new granulated aluminum oxide, which is characterized by the presence of meso- and macropores, which is favorable for mass transfer under the synthesis conditions. The influence of the presence of spinel on the main catalytic parameters and the composition of the resulting products was also investigated, and the influence of preliminary heat treatment of the initial aluminum oxide was studied. The obtained in the presence of most promising catalysts waxes are characterized by a high degree of crystallinity, which is confirmed by diffraction data, consist predominantly of linear alkanes (the content of which is 75–80%) and contain 32–34 wt.% of C35+ hydrocarbons. Electron microscopy data of the catalyst granules clearly demonstrate that the external and internal surfaces of the catalyst are filled with solid paraffins–synthesis products–during catalytic testing, but this does not lead to its deactivation. Synthesis was performed under quite mild conditions – 170 °C, 3 MPa, which distinguishes the studied catalysts from those used in industry. The introduction of spinel into the catalyst composition did not affect its main catalytic properties. Preliminary calcination of the initial granulated aluminum oxide at 750 °C leads to a positive effect on the activity of the catalyst in the synthesis of solid paraffins. For citation: Asalieva E.Yu., Sineva L.V., Gryaznov K.O., Aksenenkov V.V., Mordkovich V.Z. Possibility of producing solid paraffins by Fisher-Tropsch synthesis in a fixed-bed reactor. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 10. P. 95-102. DOI: 10.6060/ivkkt.20256810.22y.