Non-metallic Elements Research Articles

Development of a novel strategy for the quantification of ultra-trace impurity elements in high-purity magnesium using inductively coupled plasma tandem mass spectrometry

High purity magnesium is not only an important basic raw material for semiconductor and electronics industries, but also a promising new generation of electrochemical energy storage materials and biomedical materials. Impurities in high-purity magnesium affect material properties, which has become the most critical factor restricting its application. However, accurate analysis of multiple ultra-trace impurity elements in high-purity magnesium is extremely challenging. In this paper, based on the synergistic effect of N2O/H2 reaction gas mixture to eliminate spectral interference of inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), a new strategy for the quantification of 45 ultra-trace impurity elements in high-purity magnesium was proposed. The results indicated that the limits of detection (LOD) were in the range of 0.02–18.5 ng L − 1; the LODs of the challenging non-metallic elements Si and S were 18.5 and 12.2 ng L − 1, respectively; and the LODs of all the other analytes were less than 10 ng L − 1. Even under hot plasma conditions, LODs of alkali metal elements were also less than 5 ng L − 1. The spike recovery of each analyte was 93.6%–107%, and the relative standard deviation (RSD) was 3.2%–6.9%, respectively. At a 95% level of confidence, no significant differences were found between the results obtained under the optimal conditions for the analyte with the developed method and the measurement results of SF-ICP-MS. The developed method indicated low LOD, high sample throughput, and complete interference elimination, demonstrating a new avenue for the rapid determination of ultra-trace elements in high-purity magnesium.

Preparation and photocatalytic application of nonmetallic doped TiO2 films with narrow band gap

TiO2 thin film has become a widely used photocatalyst due to its stable chemical properties, suitable edge position, non-toxicity and low cost, and the film structure is conducive to recycling and loading. However, because the band gap of titanium dioxide is relatively wide, visible light is difficult to be utilized, which also limit the utilization of TiO2. In recent years, non-metallic doping has been proven to be an extraordinarily efficient methodologies to reduce band gap and improve photocatalytic efficiency of TiO2 films. In this paper, the basic principle of photocatalysis and the principle of reducing band gap by doping inorganic non-metallic elements are briefly introduced, and the preparation methods of N, C and B inorganic non-metallic elements doped TiO2 films are reviewed, as well as their functions on reducing band gap of TiO2. Finally, the research status of inorganic non-metallic element doped TiO2 thin film in photodecomposition of water and organic decomposition in catalytic solution was introduced.

Effect of interstitial carbides on tribological properties of Co21Cr21Fe21Ni21V14.5C1.5 high entropy alloy at elevated temperature

High-entropy alloys (HEAs) with high wear resistance at elevated temperatures are desired for applications like turbine engine blades and internal combustion engines. By reducing the proportion of transition metal elements, the interstitial carbide in the form of doped non-metallic element C can reduce the preparation cost of HEA and improve its mechanical properties. The effect of 1.5 at% carbon doping at different sintering temperatures on microstructure, mechanical properties, and high-temperature tribological behavior was systematically investigated. The compressive strength and strain rate of C-doped HEAs sintered at 1200 °C were 969 ± 21 MPa, 8.43 ± 0.36%, which was improved by solution strengthening and carbide pegging dislocations. The wear mechanisms of C0 alloy at high-temperature are mainly oxidation wear, adhesion wear and delamination wear, while the wear mechanism of C10 alloy is mainly abrasive wear, adhesion wear, fatigue wear and oxidation wear. The combined effect of VC, M23C6 and M7C3 carbides and σ phase plays the role of anti-wear lubrication at RT∼800 °C, and the tribo-chemical reaction generates Cr2O3, NiCr2O4, NiO, and other compounds with high-temperature stability and oxidation resistance to form a thin dense oxide glaze layer, resulting in better anti-wear and friction reduction performance of C-doped alloy than undoped alloy.

Achieving a strength-ductility combination in VCoNi medium-entropy alloy via N alloying

Single-phase FCC-structured medium-entropy alloys (MEAs) have excellent ductility, but the low strength limits their applications in engineering. In this study, non-equiatomic V32Co33Ni33Cr1N1 MEA was prepared by vacuum arc melting, and its comprehensive mechanical properties were improved by nitrogen alloying and subsequent thermo-mechanical processing. Compared with the VCoNi MEA, it was observed that nitrogen alloying inhibited the recrystallization process and contributed to the formation of nitride precipitates at the grain boundaries, significantly refining the grains. Among them, the alloy subjected to cold rolling and annealing at 900 ℃ exhibited a high yield stress of ∼ 1.1 GPa, an ultimate tensile stress of ∼ 1.5 GPa, and possessed a high fracture elongation of ∼ 25.3 %. The outstanding mechanical properties were mainly attributed to the grain refinement strengthening resulting from the nitrogen alloying and multiple twins strengthening containing annealing twins, deformation twins and multiple twinning systems. This work was expected to aid in understanding the effect of nonmetallic elements alloying on the microstructures and mechanical properties of MEAs, high-entropy alloys and traditional alloys.

Modulating the electronic structure of CoFeCNO 2D nanosheets via Ni incorporation for efficient electrochemical oxygen evolution

Electronic modulation of electrocatalytic active sites by heteroatom doping has been widely recognized as an effective synthetic strategy to further enhance the intrinsic activity of oxygen evolution electrocatalysts. Incorporation of heteroatoms with different atomic radius and electronegativity into the material's lattice helps to induce subtle distortions in the material's lattice and redistribution of electron density, thereby precisely changing the electronic structure at the atomic level and enhancing catalysis active. By adjusting the ratio of metal and non-metal elements, a series of CoFeNiCNO sheet-like oxygen evolution electrocatalysts were prepared. Electrochemical characteristics showed that the overpotential of bimetallic CoFeNiCNO catalysts corresponding to 10 mA cm−2 only needs 290 mV, the Tafel slope is 98 mV dec−1, and it also has superior electrochemical stability in alkaline solution compared with that of bimetallic CoFeCNO catalysts. The doping of Ni ions in the material is closely related to the two-dimensional sheet structure of the material. This work provides a new idea for the preparation of low-cost nanosheet electrocatalysts for oxygen evolution, which is expected to be applied on a large scale in production and life.

Responses of diversity and morphometric traits of ground beetles to soil chemical properties in industrial city of China

Industrial and agricultural activities result in the direct release of contaminants into soil, which alters and destructs the habitats of soil biota. Clarifying the effects of soil contamination on soil organisms can provide a theoretical basis for the conservation of soil organisms. In this study, 3 nonmetal elements (total C, total N, total P), 5 light metal elements (total K, Ca, Mg, Al, Na), 5 heavy metal elements (Fe, Hg, Pb, Mn, Zn) and soil pH, and 18 morphological traits of carabid species were analysed to explore the responses of spatial variation of species diversity, community composition and morphometric traits to differences of soil chemical properties in four sites (Cement Plant, Coal Coking Plant, Village and Nature Reserve) in Gujiao City, the largest coking coal production city of China. In total, 1095 carabid beetles representing 59 species were recorded, with the greatest richness and activity abundance of ground beetles were found in Cement Plant and the largest species diversity was found in Coal Coking Plant, Nature Reserve contained carabid assemblages distinct from the other three sites. As for species distribution, 14 soil chemical properties could be associated with 43.2% of the observed variation, with soil Zn, N, Ca and Mn being the most important in explaining the spatial variation of the species. Changes in the type of economic activity had a significant influence on the 18 morphometric traits of carabid species, species of Coal Coking Plant and Nature Reserve had larger morphological traits than the other two sites. Variations in morphometric traits showed a significant correlation with soil chemical properties, especially body wide and profemora length, with 14 soil factors explaining more than 60% of their variance. Soil Mg, Mn, total N and pH value contributed the most in explaining morphometric traits variability of ground beetles. In summary, changes in soil chemical properties due to industrial and agricultural activities have led to carabid species diversity, community and morphometric traits changes. Soil health management is prerequisites that contribute to conserve soil biodiversity and function in industrial areas.

Study on Difference of Gold Content Results of Electroplated Hard Gold Products

The results of inductively coupled plasma spectrometry (ICP) and fire assay for the determination of gold content in electroplated hard gold products were compared, and the reasons for the differences were explored by transmission electron microscope, differential scanning synchronous thermal analyzer, high-frequency infrared carbon sulfur analyzer, etc. The result shows that the difference between the results of inductively coupled plasma spectrometry and fire assay is mainly due to the deposition of light elements such as K and Na and non-metallic elements such as C and S in the electroplating process caused by the complex electroplating liquid system. The above elements are not involved in the test of inductively coupled plasma spectrometry, so the final gold content is higher than the true value.

Effects of metalloid Si on the microstructure and mechanical properties of Fe36Ni36Cr10Mo1Al17−XSiX alloys

Multi-component alloys with good mechanical properties and casting liquidity have become a hotspot in the materials field. Typically, the addition of minor metal elements plays a vital role in strengthening the mechanical properties. However, doping metalloid elements such as Si into multi-component alloys is also an effective method to enhance the mechanical properties. In the present study, the effect of Si (0 ∼ 4 at%) on the microstructure and mechanical properties was investigated within both as-cast and thermal mechanical treatment states. In as-cast state, all 4 alloys exhibited dendrites and interdendrites structure. The fine structure enhanced tensile strength for Si1 and improved ductility for Si2. Once the Si content reached 4 at%, both the strength and ductility dropped dramatically. Phase selective recrystallization and aging greatly increased the tensile strength and ductility simultaneously. The alloys with addition of Si had similar mechanical properties after thermal mechanical treatment process. Si2 after recrystallization and aging was considered a promising candidate for further application with a yield strength of 960 MPa, tensile strength of 1463 MPa and fracture strain of 20.5%. This work provided a new prospect to design multi-component alloys with nonmetallic elements, which may be applied to wear, corrosion and oxidation resistance fields.

Research Progress of Epoxy Asphalt Material for Roads

Asphalt is a semi-solid or solid mixture formed by hydrocarbons and non-metallic elements. It is widely applied in the fields of building waterproofing and road paving. Asphalt is a low noise, durable, and renewable pavement material. However, asphalt materials have some shortcomings such as liquefying at high temperatures and brittleness at low temperatures, which are less adaptable to different environments. Therefore, people have gradually shifted their focus to asphalt modification. This paper presents an in-depth analysis and research on the composition, structure, and performance of epoxy asphalt materials for roads, so that this material can be widely used.

A critical study of Gandhaka Shodhana

Gandhaka or Sulphur is a non-metallic solid element found in nature. Gandhaka or Sulphur is required in human body for proper functioning. It is the third most abundant mineral (after calcium and phosphorus) based on percentage of total body weight. It is the sixth most abundant macro mineral in breast milk. It is present in saliva, bile, protein, amino acids, and insulin. Sulphur is mainly present in sulphur containing amino acids like cystine. Gandhaka in the body purifies blood, aids healthy digestion, and prevents toxic build-up. In Ayurveda, Gandhaka is used in the treatment of variety of diseases since time immemorial. It as a free element cannot be utilized by the body, so in Ayurveda, first it is detoxified to get ShuddhaGandhak, and then given Bhavana of herbal ingredients that make it suitable for use. ShuddhaGandhak is combined with ShuddhaParad or purified mercury to form Kajjali which is further used to prepare Ras-Aushadhi. In combination with mercury, it is used in almost all diseases.

Nonmetallic trace elements induced rhenium co-segregation in nickel Σ5 [001](210) symmetrical tilt grain boundary

The thermally/mechanically-driven structural instability of nano- and coarse-grained polycrystalline metals originates from the unstable grain boundaries (GBs). GB segregation of solute elements could not only stabilize but also embrittle GBs. To improve GB stability and cohesion in parallel via solute segregations, in this work the segregation behavior of six non-metallic impurities X at the Σ5 [001](210) GB of nickel-based alloys, their co-segregations with Re element that has no GB segregation tendency, and segregation-induced changes in GB properties were investigated comprehensively from first-principles calculations. We discovered that these nonmetallic elements can segregate to the Ni GB and thus stabilize it, but they are GB embrittlers except B. Annealing temperature and bulk concentration have no effect on the S segregation. With the X pre-segregations, induced GB segregations of Re were observed, which lowers the excess energy and enhances the cohesive strength of all X-segregated GBs. The attractive interactions between C/N/B and Re atoms promote the Re segregation. The stabilizing and strengthening mechanisms of Re segregation were mainly attributed to the changes in Fermi level location and the increased interplanar bonding, respectively. Our findings may gain more insights into the atomic-scale GB co-segregations and stabilization of polycrystalline Ni-based alloys.

Ab initio study of the lattice distortion and the vacancy defects in multi-anion oxycarbonitride ceramics TiCNO and TiZrCNO

Multicomponent ceramics have received much attention due to the tunning physicochemical properties and the huge compositional space, while multicomponent ceramics with the mixing of multi-anion are rarely studied. In this work, the local lattice distortion and vacancy formation energy in TiCNO and TiZrCNO are systematically investigated by density functional theory calculations combining with the special quasi-random structure model. The present results show that multi-anionic mixed oxycarbonitride ceramics exhibit obvious local lattice distortion. The quantified displacive distortions of C, N, and O in TiCNO are relatively large, being in order of C < N < O, although metallic elements Ti has larger distortion than nonmetals. Within incorporative mixing of Zr in cation sublattice, the distortions of Ti, C, N, and O increase evidently, the distortion degree for nonmetal elements is still in order of C < N < O. The distortion of Ti is still the largest, whereas Zr possesses almost the smallest distortion. The electronic structure shows a close association with the degree of distortion, the larger DOS at the Fermi level corresponds to the larger distortion. The vacancy defects are further studied. Our consequences show that the vacancy formation energies of non-metal elements with large local distortions are relatively low, suggesting that the local chemical environment profoundly affects the vacancy formation energy and defect-related properties. The present study reveals the important correlation of lattice distortion with electronic structure and vacancy generation, so it is valuable to deepen the understanding of the excellent properties of multicomponent ceramics with multi-anion mixing, and develop novel multicomponent ceramics with polyanionic structures.

Photoelectric structure and magnetic changes caused by niobium disulfide adsorbing (non)-metal atoms under defects.

The property transition between metal and semiconductor is the key to improving the properties of transition metal dichalcogenides (TMDCs). The adsorption of the NbS2 compound in the defect state was adjusted for the first time. The hybrid system overwrites the original surface mechanism of NbS2 and induces indirect band gaps. This modulation mode makes NbS2 convert into a semiconductor and effectively improves the catalytic activity of the material in the system. In addition, the original local magnetic moment of the compound is concentrated in the vacancy region and is improved. The optical properties of the adsorption system indicate that NbS2 compounds can be effectively applied in visible and low-frequency ultraviolet regions. This provides a new idea for the design of the NbS2 compound as a two-dimensional photoelectric material. In the study, we assume that only one atom is adsorbed on the NbS2 supercell of the defect, and the distance between the two adjacent atoms exceeds 12.74 Å, so the interaction between atoms is ignored in the study. Adsorbed atoms include nonmetallic elements (H, B, C, N, O, F), metallic elements (Fe, Co), and noble metal elements (Pt, Au, Ag). The density functional theory (DFT) was used in the experiment. The non-conservative pseudopotential method was used in the calculation to optimize the crystal structure geometrically. The approximate functional is Heyd-Scuseria-Ernzerhof (HSE06). The calculation method includes the spin-orbit coupling (SOC) effect. The crystal relaxation optimization uses a 7 × 7 × 1 k point grid to calculate niobium disulfide's photoelectric and magnetic properties. A vacuum space of 15Å is introduced in the direction outside the plane, and the free boundary condition is adopted to avoid the interaction between atomic layers. For the convergence parameter setting, the interatomic force of all composite systems is less than 0.03 eV/Å, and the lattice stress is less than 0.05 Gpa.

Outstanding specific yield strength of a refractory high-entropy composite at an ultrahigh temperature of 2273 K

We reported on the mechanical properties and microstructural evolution of a W20Ta30Mo20C30 (at.%) refractory high-entropy composite (RHEC). The RHEC exhibited outstanding yield strength at both 2273 and 1873 K. Microstructural investigations revealed that the as-cast RHEC had a triple-phase structure consisting of FCC dendrites, HCP matrix, HCP-BCC eutectic structure, and FCC-BCC eutectoid structure, and exhibited high-density defects owing to the complex phase transformations during solidification. After annealing at 2273 K, the precipitation of the BCC phase from the FCC dendrites and the decomposition of the HCP phase into the FCC-BCC eutectoid structure was observed to significantly refine the grain sizes of all triple phases. After compression at 2273 K, the ceramic phases and solid solution precipitated out from each other, which helps to avoid persistent softening after the yielding of RHEC. Further analyses suggested that the dominant deformation mechanisms of the BCC phase and HCP phase are dislocation glide and transformation-induced plasticity; whereas those of the FCC phase are twinning- and transformation-induced plasticity. The outstanding yield strength of this RHEC at ultrahigh temperatures may originate from the high-content ceramic phases and the structural metastability of the multi-principal composition. These findings provide a novel strategy to design RHECs by alloying high-content nonmetallic elements, which contributes to further breaking through their performance limits at ultrahigh temperatures.

Effects of pyrolysis conditions and heteroatom modification on the polycyclic aromatic hydrocarbons profile of biochar prepared from sorghum distillery residues

The formation of 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) in sorghum distillery residue-derived biochar (SDRBC) was evaluated under different thermochemical pyrolysis conditions of carbonization atmosphere (N2 or CO2), temperature (300–900 °C) and doping with nonmetallic elements, i.e., N, B, O, P, N + B, and N + S. The results indicated that without surface modification, PAHs formation was 944 ± 74 ng g–1, the highest level, and 181 ± 16 ng g–1, the lowest level, at 300 °C in N2 and CO2 atmosphere, respectively. Boron doping of SDRBC significantly reduced the PAHs content (by 97%) under N2 at 300 °C. Results demonstrated that boron modified SDRBC exhibited the highest degree of PAHs reduction. Combined pyrolysis temperature and atmosphere in addition to heteroatom doping is a robust and viable strategy for efficient suppression of PAHs formation and high-value utilization of pyrolysis products of low carbon footprint.

Pt single-atom loaded on nonmetallic elements (C, N, P, S) doped ZrO2 in photocatalytic hydrogen evolution: First principles

It is of great significance to regulate the coordination environment of ZrO2 to enhance its photocatalytic hydrogen evolution activity. In this paper, non-metallic elements (A = C, N, P, S) doped ZrO2 photocatalysts are designed based on first-principles, and further loaded with single-atom Pt. The relationship between the composition and performance of photocatalysts during doping and loading of single-atom is explained through electronic properties, and their photocatalytic hydrogen evolution performance is explored. Loading and doping have a synergistic effect on the modification of ZrO2, and doping effectively improves its catalytic performance. Among them, P doping greatly reduces the Gibbs free energy of the reaction. After the introduction of Pt single atoms, Pt@ZrO2(111)-P still has the best structure for photocatalytic hydrogen evolution, and the good surface electronic activity significantly improves the hydrogen evolution reaction(HER) activity (free energy of −0.01 eV). This design provides a new catalytic model for the photocatalytic hydrogen evolution system and also provides some ideas for understanding the synergistic effects of loading and doping.

Effects of tailoring microstructure on short-term creep behavior of high Nb containing TiAl alloys under various stress levels

In this work, the short-term creep behaviors of high Nb containing TiAl alloys with different microstructure characteristics at 800 °C under a wide range of stresses of 150–350 MPa were investigated in detail. In order to tailor microstructure of high Nb containing TiAl alloys, composition design strategies were applied, including the change of Al content and the introduction of non-metallic element C and rare-earth oxide Y2O3. Microstructure analysis shows that increasing Al content from 43 at.% to 46 at.% will not only change the phase constitution by changing the solidification behavior, but also affect the existence form of element C, that is, in the form of dissolved carbon atoms in low-Al alloy and Ti2AlC precipitate in high-Al alloy. Creep results confirm that both increasing Al content and introducing C and Y2O3 can effectively reduce the steady-state creep rate and enhance the creep resistance, but the latter has a more significant effect. In addition, the creep behavior of high Nb containing TiAl alloys strongly depends on the stress level, and corresponding creep deformation mechanism changes from grain boundary/lamellar interface sliding under low stress to dislocation motion under high stress. Meanwhile, the correlation between the critical stress value on creep mechanism transition and the alloy composition/microstructure was clarified.

Cu@S-Co(OH)2 hybrid electrocatalysts with high performance for alkaline hydrogen evolution reaction

Transition metal hydroxides have superior oxygen evolution reaction (OER) activity but poor hydrogen evolution reaction (HER) performance, which greatly limits the water splitting for hydrogen production. Herein, copper modification of sulfur doped Co(OH)2 hybrid catalyst (Cu@S-Co(OH)2) was prepared by one-step of electrodeposition method which can serve as efficient hydrogen evolution reaction catalyst. In the presence of sulfur and copper, Cu@S-Co(OH)2 hybrid catalyst exhibits the best catalytic activity, showing ultralow overpotential of 42 mV at a current density of 10 mA cm−2. Compared with Co(OH)2, the overpotential is improved by nearly 100 mV as well as enhanced stability. In addition, the active site poison experiments proved that the active center is cobalt metal. Combined with the adsorption strength of the catalyst for OH and H species, it is considered that both S and Cu can enhance the adsorption of OH for Co(OH)2, while S is contributed to the adsorption of H, and Cu can promote the desorption of H. This work provides a facile method and new insight to enhance the HER activity for transitional metal hydroxides via metal and non-metallic elements co-modulation.

Deformation, Fracture and Microstructure of Metallic Materials

Metallic materials are mostly a combination of metallic elements, such as iron, aluminum, magnesium, titanium and manganese, which may also include small amounts of non-metallic elements, such as carbon, nitrogen and oxygen [...]

Air Quality Impacts on the Giant Panda Habitat in the Qinling Mountains: Chemical Characteristics and Sources of Elements in PM2.5

The wild giant panda habitat is inaccessible and far away from the main areas of human activity, so environmental pollutants entering the habitat are mainly the result of external migration and spread through the atmospheric advection and diffusion processes and particulate matter deposition. To research the variation, transmission route, chemical characteristics, and source of PM2.5 in the habitat of wild giant pandas, we set up a PM2.5 sampling point near the Shaanxi Foping National Nature Reserve (SFNNR), which is the area with the highest population density of wild giant pandas in the Qinling Mountains. The 12-month average concentration of PM2.5 was 11.3 ± 7.9 μg/m3 from July 2021 to June 2022, and the 12-month average concentration did not exceed the limit value set in the standard. In the results of our analysis of element concentrations, As and Pb were much lower than the limit standard. Si, S, P, and Cl accounted for 99.60% of nonmetallic elements, while the proportion of the six metallic elements, Na, Mg, Al, K, Ca, and Fe, was 96.27%. According to the analysis results of enrichment factor (EF) and pollutant emission sources, there were four sources for the total elements in PM2.5, which were mainly distributed in the areas around the reserve. These included dust, coal combustion, biomass burning, and traffic-related emissions, which contributed 55.10%, 24.78%, 11.91%, and 8.22% of the total element mass in PM2.5, respectively. Additionally, Pb, Cu, Zn, As, Sc, Co, Ga, Mg, and, especially, Se were severely affected by human activities (coal burning, biomass burning, and traffic-related emissions). In the villages and towns around the wild giant panda habitat, the majority of energy for cooking and heating comes from coal and biomass burning, and older vehicles with high emissions are used more frequently. Therefore, to better protect the health of and reduce the impact of environmental pollution on wild giant pandas, we put forward relevant recommendations, including upgrading the energy structure of towns and villages near the habitat to increase the proportion of clean energy, such as photovoltaic power generation, natural gas, etc.; decreasing the combustion of coal and biomass; encouraging the upgrading of agricultural diesel machines and older vehicles used in these areas; and setting limits on vehicle emissions in areas surrounding the habitat.