Addition Of Transition Metals Research Articles

Catalytic Difunctionalization of Alkenes under Visible Light Irradiation: Synthesis of Iminofuranones

Comprehensive SummaryHere, we show a cost‐effective and environmentally friendly method for synthesizing iminofuranones using visible light and the photocatalyst 2‐bromoanthraquinone. Our approach uses only oxygen as the oxidant, avoiding the need for additional transition metals and strong oxidizing agents. By employing a mixed solvent system of DMF and CHCl3 under ambient conditions, we have achieved highly diastereoselective conversions of various 2‐vinyl benzamides and alkenyl amides into functionalized iminoisobenzofuranones and iminofuranones. This versatile process is broadly applicable and enables late‐stage structural modifications of complex substrates with bioactive moieties.

Fine-Grained High-Permeability Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Mo or W) Nanocrystalline Alloys with Co-Added Heterogeneous Transition Metal Elements

This study investigates the effects of multi-transition metals on the soft magnetic properties of Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Nb, Mo, and W) nanocrystalline soft magnetic alloys. Nanocrystalline soft magnetic materials are utilized in electronic components on the basis of their permeability and low core loss. In conventional alloys such as FINEMET, Nb inhibits nanocrystal growth and promotes amorphous formation. In this research, Mo and W were used as additional transition metals to control the size of nanocrystals and explore the potential for enhancing soft magnetic properties. We confirmed that the addition of Mo and W reduced the nanocrystal size, and the activation energy for nanocrystal formation and growth showed significant benefits for nanocrystalline alloys. Consequently, the soft magnetic properties of the alloys containing Mo and W exhibited higher permeability and lower coercivity. These results suggest that multi-transition metals are effective in improving soft magnetic properties by inhibiting nanocrystal formation and growth.

Three-dimensional allium flower-like iron-cobalt sulfide nanomaterials for high-performance supercapacitors

Supercapacitors with their improved performance in high energy density and long-term cycling stability have been the growing trend in recent years for fulfilling the demand of efficient energy storage systems. Herein, we report morphology-controlled three-dimensional (3D) Allium flower-like bimetallic iron-cobalt sulfide (3D-FeCoS AF) nanomaterials on nickel foam (NF) electrodes using a single-step electrochemical deposition strategy. The self-standing bimetallic 3D-FeCoS AF nanostructures show good performance towards the supercapacitance applications. The 3D-FeCoS AF nanostructures delivered a specific capacitance of ∼375.7 F g−1 at a current density of 1.0 A/g. The possible electron cloud delocalization among the FeS nanostructures through d-bands leads to the lower charge transport resistance at the 3D-FeCoS AF electrode–electrolyte interfaces and improved conductivity. The 3D-FeCoS AF electrode demonstrated excellent specific capacity and rate performance in a 2.0 M KOH electrolyte. Owing to their enormous electrochemical active surface area (ECSA) and distinctive 3D nanosheet morphology, the present 3D-FeCoS electrode holds great potential for the fabrication of additional transition metal sulfide materials for excellent supercapacitor performances. The findings of this study suggest promising prospects for the utilization of these materials in practical supercapacitance applications.

Modulating Built‐In Electronic Configuration via Variable Al Doping for Robust Oxygen Evolution Reaction

Transition metal‐based electrocatalysts play a crucial role in the oxygen evolution reaction (OER). However, their heavy reliance on free electrons at the <i>d</i>‐band significantly limits the screening of potentially efficient, earth‐abundant alternatives. Despite extensive exploration of catalyst engineering through multi‐metal cooperation to modulate electron configuration by introducing additional transition metals, practical success remains elusive. Here, we present a straightforward electrodeposition method for preparing amorphous FeCoAl hydroxide catalysts. The introduction of Al contributes external free electrons, enabling a well‐defined electron configuration for intermediate adsorption. Al doping also adjusts the <i>d</i>‐band position of adjacent Co atoms, bringing them closer to the Fermi level and significantly enhancing intrinsic activity at the active sites. Furthermore, Al dopants facilitate rapid mass and charge transfer near the catalyst layer, promoting faster reaction kinetics. Leveraging these properties, the FeCoAl hydroxide catalyst achieves a large current density of 100 mA cm <sup>‐2</sup> at an overpotential of 340 mV, with a small Tafel slope of 29.1 mV dec <sup>‐1</sup>. Our work provides valuable insights for designing efficient electrocatalysts by leveraging free electron‐rich metal doping and expanding the parameter space for catalyst engineering.

Visible-Light-Driven Method for the Selective Synthesis of Amides and N-Acylureas from Carboxylic Acids and Thioureas.

In this work, we developed a visible-light-driven method for the selective synthesis of amides and N-acylureas from carboxylic acids and thioureas. This protocol was featured as avoidance of additional oxidants and transition metal catalysts, simple manipulations, low cost, broad substrate scope, and good functional group tolerance. As only oxygen serves as the oxidation reagent, this method provides a promising synthesis candidate for the formation of N-aryl amides and N-acylureas, including late-stage functionalization of complex pharmaceutical molecules and biologically active molecules.

Effect of transition and alkali metals on Mo2C/Al2O3 catalysts for syngas to higher alcohols

Direct production of higher alcohols remains a great challenge in syngas conversion process. Herein, MMo2C/Al2O3 and KMMo2C/Al2O3 catalysts promoted by different transition metals M (M=Co, Fe, Cu, Ni, Zn, Nb) and alkali metal (K) were prepared by impregnation method to investigate the effect on CO hydrogenation to higher alcohols under milder reaction conditions (300°C, 3.0 MPa). The catalysts were characterized with XRD, H2-TPR, and XPS. It was found that the addition of transition metals and K resulted in the decrease of low-valent Mo species on the catalyst surface, which facilitated the generation of Mo4+ during the reaction. Increase in Mo4+ content facilitates the conversion of CO to CO*, which provides more CO insertion sites for the generation of alcohols. Moreover, the introduction of K also enhances the interaction of transition metals with Mo, which accelerates the formation of alcohols in the reaction. Meanwhile, the transition metal and Mo2C work together to promote the dissociative adsorption of CO. The production of higher alcohols is facilitated by the synergistic effect of the two mentioned above. Overall, the KCoMo/Al2O3 and KFeMo/Al2O3 catalysts exhibited high selectivity for higher alcohols, reaching 73.9 % and 71.3 % for C2+OH in the alcohol products, respectively. CO conversion of KFeMo/Al2O3 catalyst can reach 84.9 % with excellent stability in the reaction. Moreover, the possible pathways of the reaction were obtained by in-situ DRIFT characterization.

Parameterization of a Fluctuating Charge Model for Complexes Containing 3d Transition Metals.

Metalloproteins widely exist in biology, playing pivotal roles in diverse life processes. Meanwhile, molecular dynamics (MD) simulations based on classical force fields has emerged as an important tool in scientific research. Partial charges are critical parameters within classical force fields and usually derived from quantum mechanical (QM) calculations. However, QM calculations are often time-consuming and prone to basis set dependence. Alternatively, fluctuating charge (FQ) models offer another avenue for partial charge derivation, which has significant speed advantages and can be used for large-scale screening. Building upon our previous work, which introduced an FQ model for zinc-containing complexes, herein we extend this model to include additional 3d transition metals which are important to the life sciences, namely chromium, manganese, iron, cobalt, and nickel. Employing CM5 charges as target for parametrization, our FQ model accurately reproduces partial charges for 3d metal complexes featuring biologically relevant ligands. Furthermore, by using atomic charges derived by our FQ model, MD simulations have been performed. These charges showed excellent performance in simulating proteomic metal sites housing multiple metal ions, specifically, a metalloprotein containing an iron-sulfur cluster and another containing a dimanganese metal site, showcasing comparable performance to those of RESP charges. We anticipate that our study can accelerate the parametrization of atomic charges for metalloproteins featuring 3d transition metals, thereby facilitating simulations of relevant systems.

Computational study of transition metal coordinated polyaniline: A first principle investigation into tuning the electronic properties of the resulting hybrid material

Tuning the electronic properties of polyaniline remains one of the most important features for the development of advanced materials in electronics. In this contribution, we use density functional theory to investigate the electronic properties of polyaniline when coordinating transition metals (Mn, Fe, Co, Cu, Zn) are embedded in the polymer structure.Importantly, the results reveal that in the presence of transition metal with high electronegativity, the coordinated polyaniline winds up with a decreased gap. Indeed, the band gap for H-PANI decreases from 0.911 eV to 0.513 eV for H-PANI-Mn (lower electronegativity) and to 0.201 eV for H-PANI-Zn (higher electronegativity). This reduction in the energy gap is attributed to enhanced electron delocalization due to increased overlap of electron wavefunctions in the hybrid structure. The results also reveal that the presence of transition metals lead to lower the chemical hardness from 3.252 eV in the case of H-PANI into 0.256 eV for H-PANI-Mn and 0.100 eV for H-PANI-Zn. Additionally, the results from molecular electrostatic potential highlight that PANI-Transition metal sustains more delocalization of charge density distribution compared to H-PANI, leading to molecule polarization which does play a crucial role in various chemical phenomena. These later reveal that the electron density polarization in polyaniline can interestingly be controlled through doping and coordinating the polymer structure with additional transition metals. Therefore, the obtained results might be used in the optimization of electrochemical charge storage in supercapacitors.

Limited dissolution of transition metals in the nanocrystalline cerium (IV) oxide

Nanocrystalline cerium (IV) oxides doped with transition metals have gained significant interest recently, mostly in the field of catalysis. Herein, we present the comprehensive studies on ceria doped with 10 mol.% of transition metals (Mn, Fe, Co, Ni or Cu) synthesized by the reverse microemulsion method. The aim of this work is to study the properties of those materials with the use of different complementary methods like XRD, SEM, TPR, and XPS and to determine the possibility of fabrication of single-phase materials with that doping level. Studies presented here prove that despite showing single-phase XRD patterns with high nanocrystallinity, in all obtained materials, the dopants are not fully incorporated in the ceria lattice. Spectroscopy studies show that additional transition metal oxides are present on the surface of all materials. Herein, we also present the analyses of L3,2-edges of transition metals in ceria, as well as high energy Ce K-edge to prove that 10 mol.% of any of those transition metals cannot be incorporated in the ceria host without the formation of additional phases. Using techniques presented here, it was found that the highest share of Mn can be dissolved in the lattice, while Cu is mostly present as a surficial Cu2O. Studies presented are an important contribution to the discussion about the solubility limits in nanocrystalline ceria and its properties which may be utilized for e.g various catalysts or as electrolytes.

Tuning the oxygen storage capacity and oxygen release properties of CeO2-based catalysts for catalytic combustion of toluene

CeO2 with varied doping transition metal was investigated to understand the oxygen storage capacity and oxygen release property of CeO2-based catalysts for toluene combustion. The order of catalytic activity was as follows: CuCeOx ≈ CoCeOx > MnCeOx > FeCeOx > NiCeOx > ZrCeOx > CeO2. Kinetic studies showed that the reaction on CuCeOx proceed via an MvK mechanism and the oxygen of catalyst was crucial factor for the toluene combustion. H2-TPR and XPS showed the addition of transition metal to CeO2 could modify the surface lattice oxygen. Moreover, the oxygen storage capacity and oxygen release properties showed the transition metal additive not only change the amount of oxygen, but also affect the oxygen mobility. A linear relationship was observed between the catalytic activity and oxygen storage capacity. Diffuse reflectance infrared fourier transform spectroscopy showed the toluene first adsorbed on the surface of catalyst, and then reacted with oxygen of catalyst to form benzyl, benzoate and benzyl carbonate species. All these results provided a new strategy to develop high performance catalyst.

Photoinduced Decatungstate Anion-Catalyzed 1,4-Difunctionalization of 1,3-Butadienes via C-H Activation.

This paper outlines an innovative three-component coupling strategy for the 1,4-difunctionalization of 1,3-butadiene, utilizing sodium decatungstate (NaDT) as a hydrogen atom transfer (HAT) photocatalyst. The photoinduced process efficiently generates homoallylic amino acid esters with 100% atom economy, employing readily available components under mild reaction conditions. This light-induced protocol eliminates the need for an additional transition metal catalysts, additives, or equivalent reducing agents. The study explored various C(sp3)-H bearing partners, butadienes, and α-iminoesters, demonstrating the versatility and synthetic utility of this method.

A deeper orbital hybridization because of more unpaired electrons in d orbital resulted in a better catalytic performance

Previous reports usually co-doping various additional transition metals to improve the NH3-SCR performance of V/TiO2 catalyst. However, seldom work understood the so-called enhancement from an atom scale. This work first selected nine elements (Me) mainly from a same VIB family or a same fourth period, and compared them in transition states of MeV/TiO2 during NH3-SCR. The dehydrogenation step of adsorbed NH3 resulted to be the key step and W substitution got the lowest dehydrogenation energy of 1.29 eV. After estimating the key atoms, the total width of Me-O-V hybridization followed the order of 1.7 eV (WV/TiO2) > 1.3 eV (V/TiO2) > 1.1 eV (CoV/TiO2) > 0.9 eV (LaV/TiO2). The deeper hybridization was attributed to a shorter Me-O-V bond. Both V and W were in a high-spin state while Co and La were in a low-spin state. Moreover, W atom had four semi full d orbitals, bigger than that (three) of V, which were more conducive to electron transfer, and resulting in the biggest overlapping of atomic orbitals. The above prediction was consistent with the afterward experimental result, in which MeV/TiO2 showed a NH3-SCR conversion order of 81 % (WV/TiO2) > 59 % (V/TiO2) > 41 % (CoV/TiO2) > 2 % (LaV/TiO2) at 300 °C. The main result of this work is in favor of designing an effective catalyst from the atom scale.

A first-principles study of the lithium storage properties of transition metal doped TM-Ti2CO2 (TM=Sc, V, Cr, Mn, Fe, Co, Ni and Cu)

Two-dimensional transition metal carbides, known as MXenes, have garnered significant interest for their potential applications in lithium-ion batteries anode materials, owing to their distinctive properties. Doping, a prevalent method for material modification, involves the substitution of metal atoms within MXenes with other elements to modulate material properties. Given that MXenes inherently contain transition metals, doping with additional transition metals presents an optimal approach for enhancing their performance. In this study, we investigated the effect of doping eight transition metals (Sc, V, Cr, Mn, Fe, Co, Ni, Cu) onto Ti2CO2, aiming to elucidate their impact on the lithium storage properties of the material. Our findings reveal that the introduction of different dopant atoms induces changes in the d-band center of the material, consequently influencing the adsorption energy of lithium ions on the MXene surface in a nearly linear fashion. What’s more, doping with Sc, Cr, and Mn atoms results in an elevation of the migration energy, while doping with Fe, Co, Ni, and Cu atoms leads to a notable increase in the open circuit voltage (OCV). Remarkably, only V atom doping demonstrates an optimal combination of suitable adsorption energy, OCV (0.66 V), and minimal diffusion energy (0.11 eV). These results underscore the significance of transition metal doping in tailoring the lithium storage properties of MXene-based anode materials, offering insights for the design and optimization of next-generation lithium-ion batteries.

Synthesis, characterization, and synergistic effects of CuS/MnO2 nanocomposite electrodes for high-performance supercapacitors

Metal oxides, metal sulfides, and their derivatives exhibit impressive electrochemical capabilities, offering potential for the creation of novel electrodes with superior performance in supercapacitors. In this study, we introduce a novel binary composite consisting of copper sulfide and manganese oxide (CuS/MnO2). This composite is designed with specific CuS and MnO2 ratios (80 % and 20 %, respectively) to explore their electrochemical behavior and optimize the performance of these nanostructures. According to morphological and structural analysis, it was observed that the synthesis process yielded high-purity nanoparticles and nanorods of CuS and MnO2. Notably, no byproducts were detected, indicating a successful synthesis process. Through a rapid pseudocapacitive charge storage mechanism, the electrochemical investigations reveal that all electrodes in a three-electrode setup tested in 3 M KOH electrolyte solution and the novel CuS/MnO2 electrode exhibit typical capacitive behavior in the potential of 0.0–0.5 V, with good reversibility and charge storage properties (specific capacitance: 451 F g−1, low resistance: 1.21 Ω, cyclic stability: 98.33 % at 4 A g−1 continuously 2000 cycles). Surprisingly, the CuS/MnO2 nanocomposite (NC) exposed high power density is about 1997 W kg−1 and a maximum energy density of 28.19 W h kg−1exceptionally is achieved. The significance of additional transition metal oxide-based electrodes in achieving noticeably better performance is demonstrated by these results.

Изучение эволюции микроструктуры и механических свойств в алюминиевом сплаве 1570 с добавкой 0,5 % гафния

Introduction. Aluminum alloys are in high demand with the aerospace industry. From the viewpoint of various performance characteristic combinations, high-magnesium aluminum alloys with the addition of transition metals, such as Zr and Sc, are among the most future-oriented alloys. Alloy 1570 is one of the most popular in this group. Recent studies demonstrated the positive effect of 0.5 % hafnium addition on as-cast structure. Study objective is to study the effect of the addition of 0.5% hafnium on the structure and properties of aluminum alloy 1570 during thermomechanical treatment. The study addresses the effect of cold rolling, homogenization, and recrystallization annealing on mechanical properties and microstructure of the specimens from alloy 1570 and similar alloy with 0.5 wt. % hafnium addition. Study methodology: for the study, ingots were cast from alloy 1570 with and without additions of 0.5 wt. % of hafnium. The resulting ingots were homogenized for 4 h at 440 °С, followed first by hot rolling and then cold rolling. Cold-rolled specimens were annealed at temperatures 340 °С to 530 °С with a holding time of 3 hours. The homogenized, cold-rolled, and annealed specimens were examined using transmission and light microscopy. In addition, homogenized and cold-rolled specimens were subjected to uniaxial tensile tests to determine the mechanical properties of the studied alloy. Results and discussion. It is revealed that in an alloy containing hafnium, after homogenization annealing, there is a slight decrease in the average particle size and an increase in its total proportion in comparison with alloy 1570. In general, 0.5 % hafnium addition does not significantly affect the mechanical properties. The number of nanoparticles in both alloys increases, as does the yield strength compared to the as-cast state. When heated, both alloys demonstrate an increase in plasticity and a decrease in strength characteristics. Studies of the annealing effect on the grain structure of the studied alloys showed that hafnium increases the tendency of alloy 1570 to recrystallize. However, additional research is required to determine the reasons for this phenomenon.

Efficient degradation of phenol in water by ball-milling modulated nitrogen-doped structured biochar

Presently, most kinds of biochar rely on the addition of transition metals to improve their electron transport capacity, thereby boosting the activation of oxidants. However, challenges such as the precipitation of transition metals and the chemical inertness of biochar are commonly encountered. Biochar with nitrogen-containing functional groups has emerged as a promising solution as oxidant activators. The nitrogen doping of biochar through ball milling is a straightforward, cost-effective, and efficient preparation method. To optimize the activation properties, a multi-step process involving roasting, ball milling, and tempering was employed to produce biochar. Sesame dregs was chosen as the precursor for this biochar. By optimizing the roasting temperature to 900 °C and using urea as the nitrogen source, biochar derived from sesame residue was successfully prepared. This biochar featured pyridine nitrogen as the primary functional group, exhibiting improved crystallinity and aromaticity. The activation of sodium persulfate (3.0 mM) with biochar eliminated phenol from wastewater with an initial concentration of 50 mg/L in just 15 minutes, achieving a remarkable mineralization rate of 96.77%. Even after undergoing six cycles of repeated use, the system consistently removed 97.73% of phenol within the same timeframe, maintaining a high mineralization rate of 86.77%. Notably, it was found that N-CN, N-6, and N-q were instrumental in stimulating reactive oxygen species (ROS), while ·OH, SO4·-, and 1O2 served as the primary ROS responsible for degrading phenol. The research also revealed a linear relationship between active oxygen sites and oxidized substances, offering insights into the mechanism of phenol degradation.

The dependence of electrocatalytic HER activity of decorated MoS2 with Cu nanoclusters

Molybdenum disulfide is a potential electrocatalytic material for water splitting with excellent stability and durability. Here, the electrocatalytic hydrogen evolution reaction performance of Molybdenum disulfide nanosheets decorated with copper nanoclusters was investigated. The Cu@MoS2–1:10 exhibited remarkable hydrogen evolution reaction activity, with an overpotential as low as 150 mV under acidic conditions. The First-principles calculations further confirmed the superior electrocatalytic performance of Cu@MoS2, with a minimum hydrogen adsorption free energy of -0.10 eV. The improved electrocatalytic activity of Cu@MoS2 arises from the accelerated charge migration at the interface. And the addition of Cu increases the number of active sites on the surface of MoS2. This work could offer insights into the advancement of additional non-precious metals and transition metal dichalcogenides.

Nucleophilic functionalization of thianthrenium salts under basic conditions.

In recent years, S-(alkyl)thianthrenium salts have become an important means of functionalizing alcohol compounds. However, additional transition metal catalysts and/or visible light are required. Herein, a direct thioetherification/amination reaction of thianthrenium salts is realized under metal-free conditions. This strategy exhibits good functional-group tolerance, operational simplicity, and an extensive range of compatible substrates.

Chemoselective reduction of aromatic nitro compounds (o-nitrophenol derivatives) using simple borane-THF without transition metal catalysts, additives, or ligands

Chemoselective reduction of aromatic nitro compounds (ortho-nitrophenol derivatives) using Borane in THF (BH3-THF) at room temperature, without using an additional metal catalyst is reported. Interestingly, nitroarenes containing two or three groups, a selective reduction of the nitro group adjacent to the hydroxy group is observed which happens to be the first Chemoselective reduction protocol for nitro groups using BH3-THF. The presence of the phenolic hydroxyl group is found to be the key that aids in hydrogen transfer to the nitro group through a cyclic transition step.

Copper Vanadium Sulfide as an Anode Material in Sodium-Ion Batteries

As the modern world is moving from non-renewable energy sources to renewable sources, such as wind and solar, energy storage devices are necessary in more than just portable electronics. Large-scale, stationary energy storage is required to combat the intermittent supply of renewable energy. Li-ion batteries, which are the current state of art in energy storage devices, will not be viable in the long term for such an application as it requires a large quantity of scarce raw materials (e.g. Li, Co). To reduce the cost and increase the long-term sustainability of batteries, more abundant energy storage materials are required. Sodium is the 6th most abundant element in the earth, making it significantly more abundant than Li. Na shares a similar chemistry to Li, helping advance research into sodium-ion batteries (SIBs). However, there are many challenges associated with SIBs, such as slower diffusion kinetics and reduced cycling stability due to the larger iconic radius of Na ions (1.02 Å (Na+) vs 0.76Å (Li+)) (1). This issue leads to incompatibility of most current anode materials used in LIBs, necessitating the identification of alternative materials (2). Transition metal sulfides (TMS) have great potential as anode materials for SIBs due to their high theoretical capacities as a result of conversion-based reactions occuring during cycling (3). However, conversion-based materials suffer from volume expansion during the sodiation and desodation process (4). CuS (covellite) has attracted a lot of attention and has a theoretical capacity of 560mA.h/g and electrical conductivity of ∼10−3Scm−1 (2,5). Unfortunately, CuS requires significant modifications to enhance its structural stability such as the formation of rGO composites or intricate morphological alteration to mitigate volume expansion during cycling. Herein, we address the addition of a second transition metal, vanadium, to form a ternary material (Cu3VS4) that enables cycling stability. Cu3VS4 is produced via a colloidal hot injection method to allow for high precision control over the morphology and phase purity. Factors such as ligand exchange, voltage profile, electrolyte selection, phase transformation (via in-situ and ex-situ studies), and SEI layer formation are also investigated to understand their contributions to the long-term stability of the cell. This study provides a mechanistic insight into the factors that affect the long-term stability of the material, taking a step closer to the production of sustainable materials for energy storage devices.