Neodymium Oxide Research Articles

The role of Keap1/Nrf2/HO-1 signal pathway in liver injury induced by rare earth neodymium oxide in mice

Objective: To investigate the role of Keap1/Nrf2/HO-1 signaling pathway in liver injury induced by neodymium oxide (Nd(2)O(3)) in mice. Methods: In March 2021, forty-eight SPF grade healthy male C57BL/6J mice were randomly divided into control group (0.9% NaCl), low dose group (62.5 mg/ml Nd(2)O(3)), medium dose group (125.0 mg/ml Nd(2)O(3)), and high dose group (250.0 mg/ml Nd(2)O(3)), each group consisted of 12 animals. The infected groups were treated with Nd(2)O(3) suspension by non-exposed tracheal drip and were killed 35 days after dust exposure. The liver weight of each group was weighed and the organ coefficient was calculated. The content of Nd(3+) in liver tissue was detected by inductively coupled plasma mass spectrometry (ICP-MS). HE staining and immunofluorescence was used to observe the changes of inflammation and nuclear entry. The mRNA expression levels of Keap1, Nrf2 and HO-1 in mice liver tissue were detected by qRT-PCR. Western blotting was used to detect the protein expression levels of Keap1 and HO-1. The contents of catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were detected by colorimetric method. The contents of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. The data was expressed in Mean±SD. Two-independent sample t-test was used for inter-group comparison, and one-way analysis of variance was used for multi-group comparison. Results: Compared with the control group, the liver organ coefficient of mice in medium and high dose groups were increased, and the Nd(3+) accumulation in liver of mice in all dose groups were significantly increased (P<0.05). Pathology showed that the structure of liver lobules in the high dose group was slightly disordered, the liver cells showed balloon-like lesions, the arrangement of liver cell cords was disordered, and the inflammatory exudation was obvious. Compared with the control group, the levels of IL-1β and IL-6 in liver tissue of mice in all dose groups were increased, and the levels of TNF-α in liver tissue of mice in high dose group were increased (P<0.05). Compared with the control group, the mRNA and protein expression levels of Keap1 in high dose group were significantly decreased, while the mRNA expression level of Nrf2, the mRNA and protein expression levels of HO-1 were significantly increased (P<0.05), and Nrf2 was successfully activated into the nucleus. Compared with the control group, the activities of CAT, GSH-Px and T-SOD in high dose group were significantly decreased (P<0.05) . Conclusion: A large amount of Nd(2)O(3) accumulates in the liver of male mice, which may lead to oxidative stress and inflammatory response through activation of Keap1/Nrf2/HO-1 signal pathway. It is suggested that Keap1/Nrf2/HO-1 signal pathway may be one of the mechanisms of Nd(2)O(3) expose-induced liver injury in mice.

Structural, Optical, and Electrical Investigations of Nd2O3-Doped PVA/PVP Polymeric Composites for Electronic and Optoelectronic Applications

In this present work, a PVA/PVP-blend polymer was doped with various concentrations of neodymium oxide (PB-Nd+3) composite films using the solution casting technique. X-ray diffraction (XRD) analysis was used to investigate the composite structure and proved the semi-crystallinity of the pure PVA/PVP polymeric sample. Furthermore, Fourier transform infrared (FT-IR) analysis, a chemical-structure tool, illustrated a significant interaction of PB-Nd+3 elements in the polymeric blends. The transmittance data reached 88% for the host PVA/PVP blend matrix, while the absorption increased with the high dopant quantities of PB-Nd+3. The absorption spectrum fitting (ASF) and Tauc's models optically estimated the direct and indirect energy bandgaps, where the addition of PB-Nd+3 concentrations resulted in a drop in the energy bandgap values. A remarkably higher quantity of Urbach energy for the investigated composite films was observed with the increase in the PB-Nd+3 contents. Moreover, seven theoretical equations were utilized, in this current research, to indicate the correlation between the refractive index and the energy bandgap. The indirect bandgaps for the proposed composites were evaluated to be in the range of 5.6 eV to 4.82 eV; in addition, the direct energy gaps decreased from 6.09 eV to 5.83 eV as the dopant ratios increased. The nonlinear optical parameters were influenced by adding PB-Nd+3, which tended to increase the values. The PB-Nd+3 composite films enhanced the optical limiting effects and offered a cut-off laser in the visible region. The real and imaginary parts of the dielectric permittivity of the blend polymer embedded in PB-Nd+3 increased in the low-frequency region. The AC conductivity and nonlinear I-V characteristics were augmented with the doping level of PB-Nd+3 contents in the blended PVA/PVP polymer. The outstanding findings regarding the structural, electrical, optical, and dielectric performance of the proposed materials show that the new PB-Nd+3-doped PVA/PVP composite polymeric films are applicable in optoelectronics, cut-off lasers, and electrical devices.

Preparation of 3D Nd2O3-NiSe-Modified Nitrogen-Doped Carbon and Its Electrocatalytic Oxidation of Methanol and Urea.

Developing renewable energy sources and controlling water pollution are critical but challenging problems. Urea oxidation (UOR) and methanol oxidation (MOR), both of which have high research value, have the potential to effectively address wastewater pollution and energy crisis problems. A three-dimensional neodymium-dioxide/nickel-selenide-modified nitrogen-doped carbon nanosheet (Nd2O3-NiSe-NC) catalyst is prepared in this study by using mixed freeze-drying, salt-template-assisted technology, and high-temperature pyrolysis. The Nd2O3-NiSe-NC electrode showed good catalytic activity for MOR (peak current density ~145.04 mA cm-2 and low oxidation potential ~1.33 V) and UOR (peak current density ~100.68 mA cm-2 and low oxidation potential ~1.32 V); the catalyst has excellent MOR and UOR characteristics. The electrochemical reaction activity and the electron transfer rate increased because of selenide and carbon doping. Moreover, the synergistic action of neodymium oxide doping, nickel selenide, and the oxygen vacancy generated at the interface can adjust the electronic structure. The doping of rare-earth-metal oxides can also effectively adjust the electronic density of nickel selenide, allowing it to act as a cocatalyst, thus improving the catalytic activity in the UOR and MOR processes. The optimal UOR and MOR properties are achieved by adjusting the catalyst ratio and carbonization temperature. This experiment presents a straightforward synthetic method for creating a new rare-earth-based composite catalyst.

Fabrication of 3D HierarchicalSphericalHoneycomb-Like Nd2O3/Co3O4/Graphene/Nickel Foam Composite Electrode Material for High-Performance Supercapacitors

A 3D hierarchical spherical honeycomb-like composite electrode materialof neodymium oxide (Nd2O3), cobalt tetraoxide (Co3O4), and reduced graphene oxide (rGO) on nickel foam (named as Nd2O3/Co3O4/rGO/NF) were successfully fabricated by combining the hydrothermal synthesis method and the annealing process. Nickel foam with a three-dimensional spatial structure was used as the growth substrate without the use of any adhesives. The Nd2O3/Co3O4/rGO/NF composite has outstanding electrochemical performance and can be used directly as an electrode material for supercapacitors (SCs). By taking advantage of the large specific surface area of the electrode material, it effectively slows down the volume expansion of the active material caused by repeated charging and discharging processes, improves the electrode performance in terms of electrical conductivity, and significantly shortens the electron and ion transport paths. At a 1 A/g current density, the specific capacitance reaches a maximum value of 3359.6 F/g. A specific capacitance of 440.4 F/g with a current density of 0.5A/g is still possible from the built symmetric SCs. The capacitance retention rate is still 95.7% after 30,000 cycles of testing at a high current density of 10 A/g, and the energy density is 88.1 Wh/kg at a power density of 300 W/kg. The outcomes of the experiment demonstrate the significant potential and opportunity for this composite material to be used as an electrode material for SCs.

Effect of rare earth oxide microparticles on mechanical, corrosion, antibacterial, and hemolytic behavior of Mg-Hydroxyapatite composite for orthopedic applications - A preliminary in-vitro study.

The current study focused on developing a multifunctional Mg-based biodegradable composite that mitigates the trade-off between strength, antibacterial, and cytotoxicity behavior for orthopedic bone implants. The composite has been reinforced with natural mineral-based Hydroxyapatite and rare earth oxide (REO): Neodymium oxide. The effect of different concentrations of REO on the mechanical, antibacterial, and corrosion properties was analyzed. The antibacterial properties were assessed against gram-positive B. Subtilis and gram-negative E. Coli bacterial pathogens. Moreover, the cytotoxicity of the composites was assessed via Hemolysis percentage calculations. In addition, the microstructure characterization was performed via FESEM, XRD, and EDS techniques, and different intermetallic phase formations were recorded. Contact angle measurements were done via the sessile drop method to analyze the impact of rare earth oxide on the surface properties of the synthesized composites and their relationship with bacterial adhesion. The corrosion studies and swelling rates were performed under PBS and DMEM solutions. The composite with the addition of 1.5% REO outperformed the experiments with a compressive strength of 126.4MPa, and a corrosion rate less than 0.2 mm/yr. The corrosion rates and degree of swelling were seen to be more stable in DMEM solution as compared to PBS. Improved antibacterial rates were observed against both pathogens after the addition of REO along with a hemolysis percentage less than 5% for Mg-HA-1.5Nd2 O3 . The composites showed increased hydrophobicity (>75%) by the addition of 1.5% REO. Hence, it was concluded that REO (Nd2 O3 ) addition to the Mg-Hydroxyapatite composite is a feasible choice as a biomaterial for bone implant applications.

Random laser emission from neodymium doped alumina lead-germanate glass powder.

Random lasing is reported for the first time, to our knowledge, in neodymium doped alumina lead-germanate (GPA) glass powder. The samples were fabricated by a conventional melt-quenching technique at room temperature, and x-ray diffraction was used to confirm the amorphous structure of the glass. Powders with average grain size of about 2µm were prepared by grinding the glass samples and using sedimentation in isopropyl alcohol to remove the coarsest particles. The sample was excited using an optical parametric oscillator tuned to 808nm, in resonance with the neodymium ion (N d 3+) transition 4 I 9/2→{4 F 5/2,2 H 9/2}. Random laser (RL) emission at 1060nm (N d 3+ transition: 4 F 3/2→4 I 11/2) was observed for an energy fluence excitation threshold (E F E r m t h ) of about 0.3m J/m m 2. Above the E F E t h , a short RL pulse in the nanosecond range is observed, corroborating the lasing process. Contrary to what one might suppose, the use of large quantities of neodymium oxide (10% wt. of N d 2 O 3) in the GPA glass, which leads to luminescence concentration quenching (LCQ), is not a disadvantage, once stimulated emissions (RL emission) occur faster than the nonradiative energy-transfer time among N d 3+ ions responsible for the LCQ.

Gamma-Ray Sensing Properties of Nd Doped Phosphate Glasses

Five selected Nd2O3 doped phosphate glass compositions are synthesized using melt quench technique. The physical properties such as density (ρ) and molar volume (Vm) are experimentally measured. The density increases whereas molar volume decreases with addition of Nd2O3 content. The radiation sensing properties for these rare earth (RE) element doped phosphate glass samples have been investigated. The photon attenuation and sensing parameters such as mass attenuation coefficient (μm), linear attenuation coefficient (μL), optimum thickness range (x opt), effective atomic number (Zeff), and mean free path (mfp) values are computed over wide gamma-ray energy range 1keV -100 GeV within framework of WinXCom software tool. The photon sensing properties of these rare earth doped phosphate glasses vary significantly on account of neodymium oxide content and photon energy. The mean free path (mfp) values of glass samples are found to decrease while the mass attenuation coefficient values rise as Nd2O3 concentration does.

Role of rare-earth oxides, conjugated with [Formula: see text], in the enhancement of power conversion efficiency of dye sensitized solar cells (DSSCs).

Different rare-earth (RE) metal-oxides nano-particles (NPs) viz. Samarium (III) oxide (Sm2O3), Neodymium (III) oxide (Nd2O3), and Gadolinium (III) oxide (Gd2O3) were synthesized using co-precipitation route, and investigated by structural, optical, and morphological studies. Findings and supporting studies were presented to understand the role of RE-metal-oxides NPs as photo-anode material for dye sensitized solar cells (DSSCs) applications. Structural analysis of prepared RE-metaloxides, by X-ray diffraction (XRD), reveals the crystalline nature of the particles ranging from 24 to 37nm. Morphological study by field emission scanning electron microscopy (FESEM) supports the crystalline nature in the nano range of the prepared RE-metaloxides particles. The observed d values of each sample support the growth of Gd2O3, Nd2O3, and Sm2O3 material. The band-gap of prepared material was estimated from the UV-VIS absorption data and Tauc relation. The observed band gap values are 3.55eV, 3.31eV, and 3.52eV for Gd2O3, Nd2O3, and Sm2O3 respectively. These values are reasonably high compare to the bulk values, indicates the nanostructure formation. Optimized RE-metal oxides NPs employed in the form of TiO2 photo anode for the fabrication of DSSCs. FESEM confirms that the Gd2O3-based photo-anode shows more uniform and decent coverage with more porosity on the TiO2. The EIS measurements of prepared DSSCs also supported the improvement in the photovoltaic output for the modified photo-anode devices as cells with modified photo-anode exhibited less charge recombination at the photo-anode/dye/electrolyte interface with increased electron lifetime leading to improved device performance as compared to the unmodified-based DSSCs. The highest efficiency 5.51% was demonstrated by [Formula: see text]/[Formula: see text] photo-anode-based DSSCs compare to Sm2O3, and Nd2O3 activated photo-anode.

Electronic, magnetic and optical properties of transition metal doped Nd2O3: A DFT insight

The structural, electronic, magnetic, and optical properties of transition metal doped rare earth neodymium sesquioxide (Nd2XO3, where X = Co, Cr, Mn, Ni, and Zn) were investigated here by first-principles simulations considering the density functional theory (DFT) framework. Comparing the energy band structures, density of states, and the overall charge density distribution, we have seen that the transition metal doping improves the application of the Nd2O3 (NDO) in many technological aspects. Spin-polarized calculations were quite satisfactorily described, and from this theoretical interpretation using DFT we’ve fruitfully explained the mechanism behind the magnetic behavior of all doped samples. The electronic and optical properties of doped NDO samples were well-tuned by transition metal atoms. Finally, we have observed that the values of total magnetization of transition metal substituted NDO samples were substantially enhanced compared to that of pure NDO, which would be very attractive in diverse applications.

Geological structure of Ustuk ore field features of mining

The article provides information on mineralization of the Ustuk mineral field with uranium and other rare metals.The distribution of radioactive elements in rocks was studied in field studies. As a result of the research, it was found that uranium-rich vanadium mineralization and secondary minerals of carnotite-tyuyamunite series were formed. Also, the primary minerals of uranium and rare earth elements were enriched with uranium and rare earth elements in the metamorphic quartzization front. A favorable environment (geochemical barrier) for quartzization of skarnoids was created and mineral deposition took place.Carriers of uranium and rare earth elements in primary minerals, consisting of 91.25% cerium, lanthanum, praseodymium and neodymium oxides, were identified as: yttrotitanite, apatite, rutile, leucoxen, orthite, uraninite, monazite, xenotime. Quartz ore deposits with iron sulfides and hydroxides have been exposed in the area.

Synthesis and Characterization of Nd2O3 Nanoparticles Using Urea As Precipitation Agent

Nanoparticles (NPs) of neodymium oxide were prepared by homogeneous co-precipitation method using neodymium nitrate and urea as precursors. X-ray diffraction (XRD) patterns have been refined by the Rietveld method and the Fourier-transform infrared spectroscopy (FT-IR) showed that the sample had a bandgap of about 4.59 eV. On the other hand, the photoluminescence (PL) spectrum indicated that the sample had a low concentration of singly ionized oxygen vacancies. The paramagnetic property of the NPs has been also tested by vibrating-sample magnetometer (VSM) measurements.

AC conductivity and dielectric behavior of polyaniline –Neodymium oxide composites

Polyaniline-neodymium oxide (PNdO) composites were created using the chemical polymerization process with ammonium persulphate as oxidizing agent. Polyaniline (PANI) and PNdO composites were prepared in various compositions viz. (10, 20, 30, 40 and 50 wt%) of Nd2O3 in polyaniline. As synthesized composites were characterized by X-ray diffraction (XRD) studies proved the presence of Nd2O3 particles in PANI matrix., AC conductivity and dielectric loss of the composites was carried out in the frequency range from 50 Hz − 1 M Hz. AC conductivity of the composites exhibited decreased values of conductivities compared to PANI. Cole-Cole plots inferred single relaxation occurring inside PANI and the composites. Dielectric tangent loss curves exhibited single peak and can be explained using Rezlescu model.

Rational design of Nd2O3 decorated functionalized carbon nanofiber composite for selective electrochemical detection of carbendazim fungicides in vegetables, water, and soil samples

Abuse of carbendazim (CBZ) leaves excessive pesticide residues on agricultural products, which endangers human health because of the residues' high concentrations. Hence, a composite consisting of functionalized carbon nanofibers (f-CNF) with neodymium oxide (Nd2O3) was fabricated to monitor CBZ at trace levels. The Nd2O3/f-CNF composite-modified electrode displays higher electro-oxidation ability towards CBZ than Nd2O3 and f-CNF-modified electrodes. The combined unique properties of Nd2O3 and f-CNF result in a substantial specific surface area, superior structural stability, and excellent electrocatalytic activity of the composite yielding enhanced sensitivity to detecting CBZ with a detection limit of 4.3 nM. Also, the fabricated sensor electrode can detect CBZ in the linear concentration range of up to 243.0 μM with high selectivity, appropriate reproducibility, and stability. A demonstration of the sensing capability of CBZ in vegetables, water, and soil samples was reported paving the way for its use in practical applications.

Circ_002363 is regulated by the RNA binding protein BCAS2 and inhibits neodymium oxide nanoparticle-induced DNA damage by non-homologous end-joining repair

Neodymium oxide nanoparticles (NPs-Nd2O3) are increasingly being used in industry and biomedicine, causing adverse health effects such as lung disease. However, the underlying molecular mechanisms controlling these adverse consequences are unknown at present. In this study, a human bronchial epithelial cell line (16HBE) was exposed to increasing concentrations of NPs-Nd2O3, and Sprague-Dawley rats were treated with NPs-Nd2O3 by intratracheal instillation. We found that NPs-Nd2O3 exposure induced DNA damage and down-regulated levels of circular RNA (circRNA) circ_002363 in 16HBE cells as well as in rat lung tissue. We also observed that circ_002363 levels in the serum of workers employed in the production of NPs-Nd2O3 diminished as the work time progressed, suggesting that circ_002363 may be a potential biomarker of lung injury. Functional experiments showed that circ_002363 significantly inhibited DNA damage induced by NPs-Nd2O3. RNA pull-down and western blot assays found that circ_002363 interacted with proteins PARP1/Ku70/Ku80/Rad50, which are critical participants in non-homologous end-joining (NHEJ) DNA repair. Moreover, we found that formation of circ_002363 was regulated by the RNA binding protein Breast Carcinoma Amplified Sequence 2 (BCAS2). The BCAS2 protein affected circ_002363 expression through interaction with Pre-DNA2, the host gene of circ_002363, in NPs-Nd2O3−exposed 16HBE cells. In conclusion, our findings show first that circ_002363, which is regulated by BCAS2, acts as regulator of DNA damage via the NHEJ pathway. These results enhance our understanding of the regulatory mechanisms controlling the actions of circular RNAs and highlight the relationship between genetics and epigenetics in the development of diseases following exposure to environmental chemicals.

Effect of rare earth Nd3+ doping contents on physical, structural, and magnetic properties of Co–Ni spinel ferrite nanoparticles

Rare earth (RE) low doping has a significant influence on the structural, morphological, and magnetic properties of spinel ferrite nanoparticles. Therefore, rare earth neodymium (Nd) oxide was fully doped into spinel ferrite with a composition of Co0.80Ni0.20NdxFe2–xO4 (x = 0.0, 0.05, 0.10, and 0.15) using the sol-gel auto combustion method. Structural analysis of the synthesized samples with low doping of Nd using X-ray diffraction (XRD) and Rietveld refinements reveals a pure single-phase cubic structure, while the second phase appears with increasing content of Nd3+ at x = 0.10 and 0.15. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) show well-shaped spherical grains within the nanometer range of the pure Co0.80Ni0.20Fe2O4 sample, while larger grains with the presence of agglomeration are observed with doping of Nd3+ into the spinel ferrite nanoparticles. The magnetic parameters, i.e., saturation magnetization Ms, remanence and magnetic moments exhibit decreasing trend with Nd3+ doping and Ms values are in 65.69 to 53.34 emu/g range. The coercivity of the Nd-doped Co–Ni spinel ferrite sample was calculated to be 1037.76 to ∼827.24 Oe. This work demonstrates remarkable improvements in the structural and magnetic characteristics of Nd-doped Co–Ni spinel ferrite nanoparticles for multiple versatile applications.

Neodymium Oxide (Nd2O3) as Passive Q-switcher for Pulsed Fiber Laser Generation in C-band Region

This work demonstrate Neodymium Oxide (Nd2O3) film as a passive saturable absorber (SA) for pulse generation within C-band region. The saturable absorber was fabricated from Nd2O3 powder, and polyvinyl alcohol (PVA) was used to form a film. The all-fiber ring cavity configuration was used in the experiment. The Q-switching operated with the pump power from 60 mW to 120 mW. The repetition rate increases from 52 kHz to 77 kHz, while the pulse width shown decrement of 7.4 µs to 5.3 µs. The signal-to-noise ratio obtained of the fundamental frequency is 64 dB. The maximum output power and pulse energy are 3.6 mW and 4.6 nJ respectively. The maximum peak power obtained is 0.87 mW.

A copper oxide functionalized neodymium oxide hybrid nanostructure interconnected with modified glassy carbon electrode (CuO–Nd2O3/GCE) for electrochemical determination of Malathion pesticide

A copper oxide functionalized neodymium oxide hybrid nanostructure interconnected with modified glassy carbon electrode (CuO–Nd2O3/GCE) for electrochemical determination of Malathion pesticide

Enhanced phosphate removal from water by hydrated neodymium oxide-based nanocomposite: Performance, mechanism, and validation

Phosphorus (P) control has been recognized as an imperative task to mitigate water eutrophication and settle the imminent shortage of P resources. Despite intensive effort put into this matter, it is still generally challenging for the current methods to remove and even potentially recover phosphorus (as phosphate) from complicated water matrices. To this end, we proposed a novel nanocomposite via coupling polystyrene anion exchanger (PsAX) with hydrated neodymium oxide (HNdO) nanoparticle for selective removal of phosphate. The developed nanocomposite, i.e., HNdO-PsAX, exhibited quite stable and efficient phosphate adsorption over a wide pH range of 3.0–10.0 with the maximum adsorption capacity as 85.4 mg P/g. It also showed satisfied anti-interference against various competing substances; notably, HNdO-PsAX obviously outperformed Phoslock, a commercial lanthanum-based adsorbent exclusively for phosphate sequestration, particularly under the interference of bicarbonate and humic acid, which were admitted as the paralyzing factors for Phoslock. The superior affinity of HNdO-PsAX towards phosphate, driven by the specific Nd-P inner-sphere complexation as evidenced by XPS, FT-IR, and the lattice evolution of HNdO nanoparticle, renders the nanocomposite eminently suitable for sequestrating trace phosphate. Fixed-bed treatment validated that HNdO-PsAX was capable of treating ∼11,800 bed volume of a simulated wastewater (from 2.0 to below 0.5 mg P/L), approximately 12 times higher than that of the previously reported Fe-based nanocomposite (HFO-PsAX, ∼ 900 BV); also, a satisfactory outcome in treating authentic municipal wastewater by HNdO-PsAX and the feasibility of regenerating the exhausted one by a binary NaOH-NaCl solution were recognized. This work provides a new potion of enhanced phosphorous control for surface water and wastewater.

Ammonia synthesis using Co catalysts supported on MgO–Nd2O3 mixed oxide systems: Effect of support composition

This study presents the use of emerging support materials based on mixed magnesium–neodymium oxides for the dispersion of the Co metal for ammonia synthesis. A series of cobalt catalysts using mixed MgO–Nd2O3 oxide supports with different Mg/Nd molar ratios (2, 4, 7, 10, and 12) was successfully prepared. The N2 physisorption, XRD, HR-TEM, STEM-EDX, TPR/TG-MS, H2-TPD, and CO2-TPD studies of these systems revealed a strong correlation between the composition of the support and the overall catalyst performance. It was found that varying the Mg/Nd molar ratio caused a gradual change in the textural, structural and adsorption properties. The difference in the activity of the Co/MgO–Nd2O3 catalysts towards ammonia synthesis was mainly attributed to the different surface adsorption properties. The highest number of basic sites on the catalyst surface was noted for the support with the Mg/Nd molar ratio of 10. Also, the highest Co dispersion was obtained on this support, leading to the best distribution of Co particles with the smallest Co particle size. As a result, the Co/10MgO–Nd2O3 catalyst demonstrated superior activity for ammonia synthesis compared to other catalysts. The use of a binary composite support consisting of MgO and Nd2O3 with the properly selected ratio of each component is beneficial in terms of catalyst activity, stability and cost compared to single-oxide supports.

Oxidative coupling of methane over strontium‐doped neodymium oxide: Parametric evaluations

AbstractSince its discovery in 1982, oxidative coupling of methane (OCM) has been considered one of the most promising approaches for the on‐purpose synthesis of ethylene. The development of more selective catalysts is essential to improve process economics. In this work, undoped neodymium oxide as well as neodymium oxide doped with high (20%) and low (2.5%) levels of strontium were tested in a high‐throughput fashion covering a wide range of operating conditions. The catalysts were shown to be able to achieve greater than 18% C2+ yield. Space velocity was shown to play a significant role in C2+ selectivity. For a methane to oxygen feed ratio of 3.5, selectivity increased with increasing space velocity, reaching a maximum of 62% at a methane conversion of 30% at an optimal space velocity of ~250,000 ml/h/g. The difference in activity between the three samples was linked to the contribution of different oxygen centers.