Impact Of Transition Metals Research Articles

Transition metals tailoring of phosphorus-doped gallium nitride nanotubes as sensors for N-butenyl homoserine lactone (BHL): A computational study

This investigation is focused on the impact of transition metals (Ag, Au, and Cu) encapsulations of phosphorus-doped gallium nitride nanotubes (P@GaNNTs) to achieve precise detection and sensing of N-Butenyl homoserine lactone (BHL), which is a biomarker for urinary tract infection, within the framework of density functional theory (DFT) computation at the B3LYP-D3(BJ)/def2SVP method. Adsorption studies unveil the adsorption energies for BHL detection across the systems, with BHL_Cu_P@GaNNT displaying the most favorable adsorption energy of −1.79247 eV and BSSE correction (−1.7685 eV). Additionally, sensor mechanisms are elucidated through Fermi energy level (EFL) calculations, revealing distinct values of 4.748, 4.242, 5.052, and 3.864 for BHL_Ag_P@GaNNT, BHL_Au_P@GaNNT, BHL_Cu_P@GaNNT, and BHL_P@GaNNT, respectively. These values signify variances in charge transfer dynamics upon BHL interaction. In essence, this study lays the foundation for the development of highly efficient biosensors with exceptional biomarker detection capabilities, particularly in the context of urinary tract infections (UTIs). It opens new avenues in the realm of biosensing technology, promising innovative solutions for healthcare and diagnostics.

The impact of transition metals (Cr, Mn, and Co) on the performance of the 10%Ni/Al2O3-10%CeO2 catalysts in combined CO2 reforming and partial oxidation of methane

This study explores the efficacy of Cr, Mn, and Co promoters in enhancing the performance of 10%Ni/Al2O3-10%CeO2 catalysts during methane combined reforming process, emphasizing improved metal dispersion and reduced carbon formation. The supports and catalysts were synthesized through mechanochemical and impregnation methods, respectively, and characterized using XRD, BET, TPR, TPO, and FESEM analyses. The synthesized catalysts exhibited a high BET surface area, ranging from 195 to 172 m2 g-1, along with a mesoporous structure characterized by pore sizes between 2 and 12 nm. The introduction of Cr significantly enhanced catalyst performance, resulting in 70.5 % CH4 and 69.1 % CO2 conversions in dry reforming. TPO analysis indicated reduced carbon deposition on promoted catalysts by enhancing Ni dispersion and carbon reactivity. The 10%Ni–3%Cr/Al2O3-10%CeO2 catalyst demonstrated stability over 440 min at 700 °C, achieving 84.9 % CH4 and 68.1 % CO2 conversions in combined reforming. The TPO analysis indicated an absence of carbon deposition on the catalyst surface during combined reforming, which was corroborated by the FESEM analysis. Furthermore, the influence of operating parameters on catalyst efficiency in both dry and combined reforming processes was investigated. As GHSV increased from 8000 to 24,000 ml/h.gcat, CH4 conversion declined in dry reforming and combined reforming, dropping from 77 % to 66 % and from 86 % to 84 %, respectively. Also, in both processes, increasing the oxidizer contents (CH4: CO2 from 2:1 to 1:2, CH4: CO2: O2 from 1:1:0 to 1:1:0.35) led to an increase in CH4 conversion, while CO2 conversion decreased.

Investigating the magnetic domain structure and photonics characters of Singled Phased hard ferromagnetic Ferrite MFe3O4 (M= Co2+, Zn2+, Cd2+) Compounds

The impact of transition metals on ferrite (iron (III) oxide) compounds is investigated in this study. Ferrite samples were synthesized using the co-precipitation method. X-ray analysis unveiled the presence of the Fe-phase in the trivalent state, showcasing a single-phased cubic spinel framework with a preferred orientation along the (311) reflection plane. Crystallite sizes were determined for CdFe3O4, ZnFe3O4, and CoFe3O4 utilizing the Scherer equation, yielding values of 10.54 nm, 18.76 nm, and 32.63 nm, respectively. Zinc ferrite displayed an intermediate photonic nature compared to cobalt and cadmium ferrite, with cadmium ferrite showing high optical losses and cobalt ferrite exhibiting minimal optical losses. EDX analysis confirmed the presence of Zn2+, Co2+, Fe3+, Cd2+, and O2? ions in the correct ratios, supporting the intended stoichiometric composition. Optical assessment revealed that CoFe3O4 nanoparticles are well-suited for optoelectronic devices, ultraviolet detectors, and infrared (IR) detectors. VSM measurements of cobalt ferrite exhibited higher coercivity and magnetic saturation compared to other samples. Photoluminescence (PL) spectroscopy revealed multiple colors, including cyan, green, and yellow, at different wavelengths for the ferrite samples. These findings suggest that the synthesized samples are suitable materials for high-frequency devices owing to their robust magnetic properties. Cadmium ferrite displayed a multi-magnetic domain structure, contrasting with the single-magnetic domain structure observed in zinc and cobalt ferrite.

A DFT study on the switching energy of multiferroic capacitor with stable single-phase multiferroic material

In spintronic technology, bismuth ferrite BiFeO3 (BFO) is a potential multiferroic material for multiferroic capacitor application. In present study, the impact of transition metals X = Co, Ni, Mn, Ti at the Fe-site and rare earth element lanthanum (La) at the Bi-site is investigated using DFT calculation in order to improve the structural stability, spin polarized electronic, and dielectric properties of bismuth ferrite for switching energy of multiferroic capacitor applications. The calculations are carried out in the Cambridge Serial Total Energy Package (CASTEP) code by using ultra-soft pseudopotential (USP). The substitution of La and X atoms alters the spin-polarizedelectronic and dielectric characteristics of BFO, leading to an increase in the density of states (DOS) around the Fermi level. The observed descending order of the structure stability of co-doped BFO is given as: LaCo > LaNi > LaMn co-doped BFO system. LaCo and LaNi co-substituted systems have shown high spin polarizations of 87.08 % and 82.20 % respectively. Low switching energies of 0.52 aJ and 0.72 aJ, respectively have been observed for LaCo and LaNi co-doped BFO systems for multiferroic RAM capacitor applications.

The thermoelectric performance in transition metal-doped PbS influenced by formation enthalpy

Transition metals have excellent valence electrical properties and unique electronic state distribution and are regarded as potential materials for improving thermoelectric performance. However, the impact of transition metals on thermoelectric materials is restricted to the solid solution limit and doping efficiency, reinforcing the shortcomings in systematic research. Here, thermoelectric properties of transition metal (Ti, V, Cr, Zr, Nb, Mo)-doped PbS are compared and analyzed systematically based on the formation enthalpy. The DFT calculation indicates that the doping (except Zr) leads to the bandgap expansion and the density of states distortion near the Fermi level, while the localization property of the latter results in an invalid resonance level. The formation enthalpy dominates the carrier concentration due to the opposite trend of carrier concentration and formation enthalpy. The formation enthalpy of Zr, Ti, and Nb doping is more negative than others, leading to the more significant optimization of carrier concentration. The Moss–Burstein effect promotes the bandgap expansion, leading to weaker bipolar effects for Zr, Ti, and Nb doping. Eventually, the thermoelectric performance for Ti, Zr, and Nb doping is superior to others at high temperature. The Hume-Rothery rule of the formation enthalpy supplementation is more suitable for the doping and alloying in thermoelectricity. Thermodynamic stability analysis based on the formation enthalpy contribute the PbS-based thermoelectric devices evaluation. The present finding demonstrates the significant effect of formation enthalpy on the thermoelectric properties of PbS and provides a useful avenue for the doping modification and thermodynamic stability analysis of other thermoelectric alloy materials.

Device Performance as a Metrology Tool to Detect Metals in Silicon

Herein, the impact of transition metals (TMs) on the electrical device performance, i.e., carrier lifetime, leakage current, low‐frequency noise, photocurrent, and solar cell efficiency is reviewed. Defect information is obtained by using either simple device structures such as metal‐oxide‐semiconductor (MOS) capacitors and pn‐diodes or transistors. The impact of metals on complementary MOS (CMOS) image sensors (CIS) and solar cells is also briefly addressed. Scaled devices are a power tool to detect small‐sized defect clusters or even single metal atoms. Examples are given for a variety of both slow‐ and fast‐diffusing metals. The final section outlines the power of density functional theory (DFT) ab initio calculations to support the experimental observations and to get a deeper physical insight into the defect structure.

Mitigation of copper toxicity by DNA oligomers in green paramecia

Impact of transition metals which catalyze the generation of reactive oxygen species (ROS), on activation of cell death signaling in plant cells have been documented to date. Similarly in green paramecia (Paramecium bursaria), an aquatic protozoan species harboring symbiotic green algae in the cytoplasm, toxicities of various metallic ions have been documented. We have recently examined the effects of double-stranded GC-rich DNA fragments with copper-binding nature and ROS removal catalytic activity as novel plant cell-protecting agents, using the suspension-cultured tobacco cells. Here, we show that above DNA oligomers protect the cells of green paramecia from copper-induced cell death, suggesting that the phenomenon firstly observed in tobacco cells is not limited only within higher plants but it could be universally observable in wider range of organisms.

Cell-mediated LDL oxidation: The impact of transition metals and transferrin

Activated monocytes release oxygen radicals by respiratory burst and oxidative damage can be accelerated by transition metals. We investigated the cell-mediated and metal-catalysed in vitro oxidation of low-density lipoproteins (LDL), as well as the impact of the metal-binding protein transferrin (Tf). LDL oxidation was measured by monitoring the increase in fluorescence (350/440 nm excitation/emission). Maximal respiratory burst by U937 cells was achieved after 96 h differentiation with retinoic acid and dihydroxyvitamin D 3 followed by stimulation with opsonised zymosan. Addition of activated cells resulted in the LDL oxidation, even in the absence of transition metals. Moreover, activated cells greatly enhanced metal-catalysed oxidative modifications, especially in the presence of copper. By binding metals, Tf was able to strongly impair this process. In conclusion, by generating oxygen radicals, activated U937 cells were able to oxidise LDL. The oxidising process was most pronounced in the presence of copper and could be blocked by Tf.

Impact of transition metals on reductive dechlorination rate of hexachloroethane by mackinawite.

Mackinawite, an iron monosulfide, has been shown to be a potential reductant for chlorinated organic compounds under anaerobic conditions. Chlorinated organic compounds are often found with inorganic contaminants. This study investigates the impact of various transition metals on the reductive dechlorination by mackinawite using a readily degradable chlorinated organic compound, hexachloroethane (HCA). Different classes of transition metals show distinct patterns in their impact on the HCA dechlorination: 10(-3) M Cr(III) and Mn(II) (hard metals) decreased the dechlorination rates, while 10(-4), 10(-3), and 10(-2) M Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) (intermediate/soft metals) increased the rates. The tested hard metals, due to their weak affinity for sulfides, are thought to form surface precipitates of hydroxides around FeS under the experimental conditions with these hydroxides hindering the electron transfer between FeS and HCA. Due to their high affinity for sulfides, however, the tested intermediate/soft metals can react with FeS in various ways: precipitation of pure metal sulfides (MS), formation of metal-substituted FeS by lattice exchange, and coprecipitation of the mixed sulfides in a Fe-M-S system. Fe(II), released as a result of the interaction of FeS with intermediate/soft metals, enhances the HCA dechlorination at the doses of 10(-4) and 10(-3) M through sorbed or dissolved Fe(II) species, while Fe(OH)2(s) formed at the higher dose of 10(-2) M also enhances the reductive dechlorination. Rate increases observed in Co(II)-, Ni(II)-, and Hg(II)-amended systems are not simply explained by the formation of pure MS; instead, metal-substituted FeS or coprecipitated sulfides are thought to be responsible for the significantly increased rates observed in these systems.