Facile Co-precipitation Method Research Articles

Stoichiometric-Ratio-Controlled Fe and Ni Non-noble Metal Catalysts Supported on γ-Al2O3 for Turquoise Hydrogen and Carbon Nanotubes Production.

Herein, we synthesized a series of catalysts comprising iron (Fe), and nickel (Ni) supported on γ-Al2O3 nanopowder (Fe-Ni/γ-Al2O3) by controlling the stoichiometric ratio of the metals through the facile co-precipitation method. The ratio of Fe and Ni on the γ-Al2O3 support varied from 0 to 70 weight percent (wt%). The freshly prepared catalysts' phase, structure, and crystallinity exhibited variability as the Fe and Ni stoichiometric ratios were altered. The catalyst demonstrated effective performance in methane cracking, producing turquoise hydrogen and carbon nanotubes (CNTs) using a temperature-programmed reactor coupled with mass spectrometry. It was observed that the Fe3Ni4 catalyst, comprising 30% Fe and 40% Ni, exhibited a maximum methane conversion rate of 85% and a hydrogen yield of 72.55%. Moreover, the values of turnover frequency (2.38 min-1) indicated that the Fe3Ni4 had a better production rate and was consistent with the conversion process throughout the reaction. The structural attributes of the spent catalysts were examined, revealing variations in the lateral length, uniformity, and diameters (~33 to 56 nm) of the produced Carbon Nanotubes (CNTs) when transitioning from catalyst Fe0Ni7 to Fe7Ni0. The investigation underscored the significance of metal stoichiometrically controlled catalysts and their catalytic efficacy in methane cracking applications.

Visible-light-driven photocatalytic for degrading tetracycline wastewater by BiOI/Bi2O3 Z-scheme heterojunction

Direct Z-scheme heterojunctions can exhibit enhanced redox capacity in redox reactions compared to conventional heterojunctions. In this study, BiOI/Bi2O3 Z-scheme heterojunctions were synthesized by a facile co-precipitation and calcination method using BiOI as a precursor, and its photocatalytic activity was investigated by degrading tetracycline antibiotics in aqueous environment. Under visible light, the degradation efficiency of tetracycline reached 80.01 % and the photocatalytic degradation rate constant reached 0.0116 min−1 when the molar ratio of Bi and I in BiOI/Bi2O3 composites was 1:1, which were 2.8 and 4.8 times higher than that of pristine BiOI (0.0041 min−1) and Bi2O3 (0.0024 min−1), respectively. The heterojunctions exposed excellent stability that maintained at 78.80 % after four cyclic tests. The ascendant photocatalytic performance can be attributed to the formation of direct Z-scheme heterojunctions, which improves the separation and transfer efficiency of the photogenerated electron-hole pairs, and ·O2- is the main active substance in the degradation process. This research provides a green and convenient method for preparing photocatalytic heterojunctions, which is conducive to promoting the development of photocatalytic degradation of refractory pollutants under visible light.

Electrochemical in-situ probing of heterocatalytic green reduction of 4-nitroaniline by novel non-noble CuO/Co3O4 nanocomposites

Nobel metals are commonly used catalysts in reactions due to their excellent catalytic activities. Transition metals, too, possess good catalytic activity due to the availability of vacant d-orbitals that provide avenues for electron exchange during reactions. In this work, the performance of CuO/Co3O4 (CCO) catalyst is evaluated. The catalyst is prepared by a facile coprecipitation method. X-ray diffraction, Fourier transform infrared spectroscopy, HRTEM, Ultraviolet spectroscopy, Scanning electron microscopy and X-ray photoelectron spectroscopy techniques were used to study the material properties. XRD analysis confirms the formation of CCO heterostructure with supporting evidence from FTIR, HRTEM and XPS. The catalyst shows optical bandgap contributions of CuO and Co3O4 at 1.6 eV and 2.4 eV, respectively. The SEM analysis shows the presence of agglomerates with a mean length of 111 ± 3 nm. The prepared catalyst is employed for the 4-nitroaniline reduction using sodium borohydride. The kinetics of the reduction reaction were studied, and an apparent rate constant of 0.323 min−1 was estimated. The catalyst shows a turnover frequency of 1.44 min−1 and 100% recyclability up to 5 cycles that are competitive with noble metal and rare-earth-based catalysts. The fast reduction of 4-NA is attributed to the novel p-p type isojunction formed by the heterostructure of CCO. Additionally, extensive electrochemical analysis has been used as an in situ probe to monitor the reduction reaction. Accordingly, the study shows the different intermediary reduction species formed in the process of reduction, adding evidence to the proposed mechanism.

A LiPF6 gel-polymer electrolyte for a solid-state supercapacitor with polyaniline/MnCo layered double hydroxide nanosheets as active electrode material

This paper introduces a novel solid-state electrolyte for supercapacitors (SCs), employing a LiPF6 gel polymer coupled with innovative electrodes composed of MnCo-layered double hydroxide (LDH) nanosheets. The newly synthesized LiPF6 gel polymer electrolyte exhibits superior ionic conductivity and mechanical flexibility, making it an ideal candidate for advanced energy storage devices that require bending and twisting capabilities. The thermal analyses and morphological characterizations were evaluated using DSC, XRD, FT-IR, BET, TEM and FE-SEM techniques. The MnCo-LDH nanosheets, synthesized via a facile co-precipitation method, served as the electrode material. It was expected that the collaborative interaction between the LiPF6 polymer matrix and the multifaceted nanoflower-shaped MnCo-LDH nanosheets could improve electron mobility and supply an increased surface area for redox processes. Electrochemical analyses, including cyclic voltammetry and galvanostatic charge-discharge tests, reveal a marked improvement in the specific capacitance, rate capability, and cyclic stability of the assembled SCs. This novel electrolyte-electrode configuration yielded a specific capacity of up to 198.66 F g−1 at 1.6 A g−1 and exhibited rate performance with retention of 89.15 % at an elevated current density of 10 A g−1 for 2-Hydroxyehtyl cellulose: LiPF6 gel polymer with molar ratio of 1: 2. Moreover, it demonstrates enduring cyclic stability with no capacity decay after 10,000 cycles. We delineated the pivotal role of Mn in facilitating electron transfer kinetics and moderating interactions with Co ions. The introduction of strain within the LDH structure promulgates a conducive environment for electrochemical reactions.

One-step designing of spinel CuCr2O4/Cr2O3 nanostructures as efficient positive electrode for a high-performance supercapacitor

Although transition metal oxides (TMOs) have theoretical benefits for supercapacitors (SCs), their low conductivity and stability restrict their wide practical utilization. In this context, TMOs-based composite materials with a spinel structure have emerged as efficient positive electrodes for high-performance SCs. It could improve energy storage properties such as capacitance, stability, and energy density. In light of this, in this work, we proposed a nanostructured spinel CuCr2O4/Cr2O3 composite via a facile one-step coprecipitation method. Owing to the advantages of abundant reactive sites, effective electron transport, desirable electrical conductivity, better surface area, mesoporous channels, and synergistic effects of the two, the energy storage properties of the composite on nickel foam (CuCr2O4/Cr2O3@NF) were significantly improved. The resultant CuCr2O4/Cr2O3@NF electrode material shows a high capacitance (capacity) of 1027.5 F g–1 (411 C g–1) at a current density of 1 A g–1. Besides, the composite electrode exhibits rapid faradaic reactions and retains structure integrity over 5000 cycles, affording a good cyclic stability of 86.01% of its initial capacitance at 15 A g–1. Moreover, the asymmetric device (CuCr2O4/Cr2O3@NF//AC@NF) composed of CuCr2O4/Cr2O3@NF (positive electrode) and AC@NF (negative electrode) delivers an ideal energy density of 38.89 Wh Kg–1 at 800.02 W kg–1, which surpasses the recent spinel metal chromate-based devices and maintains 88.67% of its capacitance after 5000 charge-discharge cycles. This work may open the path for combining two effective materials to form a multifaceted structure with enhanced energy storage properties.

Effect of mixed metal ions and incorporation of activated carbon on the physiochemical and catalytic properties of spinel based (Ni,Fe)Co2O4@C nanoparticles

The challenge of producing cost-effective oxygen electrocatalysts for the oxygen reduction reaction (ORR) continues to impede the advancement of fuel cell technology. Herein, we report the effect of Ni and activated carbon on mixed metal (Ni,Fe)Co2O4 and (Ni,Fe)Co2O4@C spinel oxide nanoparticles synthesized by facile and versatile co-precipitation method followed by the physio-chemical, morphological properties and electrochemical analysis towards oxygen reduction reaction. The formation of FeCo2O4, (Ni,Fe)Co2O4 and (Ni,Fe)Co2O4@C nanoparticles was confirmed with X-ray diffraction and Raman analysis while D and G band revealed the presence of carbon in the (Ni,Fe)Co2O4@C nanoparticles. The Brunauer–Emmett–Teller analysis reveals the mesoporous behaviour of the synthesized multi-metal oxide nanoparticles. X-ray photoelectron spectroscopy analysis reveals the presence of Co3+/Co2+, Fe3+/Fe2+, Ni3+/Ni2+, O1s and C1s confirms the formation of complex (Fe3+Co2+)(Ni2+Ni3+Fe2+Fe3+Co3+)2O4 spinel structure. The ionic radii of the Co, Fe and Ni ions plays a vital role in the formation of complex spinel structures. The ORR analysis was studied by electrochemical analysis and observed (Ni,Fe)Co2O4 outperformed FeCo2O4 in terms of onset potential and current densities for the ORR. (Ni,Fe)Co2O4@C exhibited the highest catalytic activity with −2.18 mAcm−2 at 0.1 V vs RHE, which is relatively comparable with that of commercial Pt/C. Furthermore, the electrocatalytic analysis revealed the ORR mechanism adheres to the direct "4e−" process. The intermetallic interactions between the Co, Fe and Ni ions along with high crystallinity, significant surface area, high porosity, and the influence of carbon incorporation that are all contribute to the improved electrocatalytic activity of the cobalite-based multi-metal spinel oxides.

High-Entropy and Component Stoichiometry Tuning Strategies Boost the Sodium-Ion Storage Performance of Cobalt-Free Prussian Blue Analogues Cathode Materials.

Prussian blue analogs (PBAs) are appealing cathode materials for sodium-ion batteries because of their low material cost, facile synthesis methods, rigid open framework, and high theoretical capacity. However, the poor electrical conductivity, unavoidable presence of [Fe(CN)6] vacancies and crystalline water within the framework, and phase transition during charge-discharge result in inferior electrochemical performance, particularly in terms of rate capability and cycling stability. Here, cobalt-free PBAs are synthesized using a facile and economic co-precipitation method at room temperature, and their sodium-ion storage performance is boosted due to the reduced crystalline water content and improved electrical conductivity via the high-entropy and component stoichiometry tuning strategies, leading to enhanced initial Coulombic efficiency (ICE), specific capacity, cycling stability, and rate capability. The optimized HE-HCF of Fe0.60Mn0.10-hexacyanoferrate (referred to as Fe0.60Mn0.10-HCF), with the chemical formula Na1.156Fe0.599Mn0.095Ni0.092Cu0.109Zn0.105 [Fe(CN)6]0.724·3.11H2O, displays the most appealing electrochemical performance of an ICE of 100%, a specific capacity of around 115 and 90 mAh·g-1 at 0.1 and 1.0 A·g-1, with 66.7% capacity retention observed after 1000 cycles and around 61.4% capacity retention with a 40-fold increase in specific current. We expect that our findings could provide reference strategies for the design of SIB cathode materials with superior electrochemical performance.

Photothermal effect enhanced antibacterial activity of CuAl-layered double hydroxides

CuAl-layered double hydroxides (CuAl-LDH) with Cu/Al atomic ratios of 2:1 and 3:1 are prepared by a facile coprecipitation method. The as-prepared CuAl-LDH have hexagonal crystalline structure and possess photothermal responsive ability. Upon 808 nm near-infrared laser irradiation for 10 min, CuAl-LDH-3 with a Cu/Al atomic ratio of 3:1 demonstrated rapid temperature elevation of 53 °C. Moreover, the dissolution rate of copper ions from CuAl-LDH increases with the increase of Cu/Al atomic ratio, and can be further promoted by irradiation. CuAl-LDHs are noncytotoxic to human umbilical vein endothelial cells and demonstrate excellent photothermal antibacterial performance against Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae), respectively. CuAl-LDH-3 displays the better antibacterial capacity attributed to the synergistic effects of the photothermal effect induced release of high concentration copper ions and the generation of reactive oxygen species (ROS). This work offers novel LDH-based antibacterial materials with photothermal and enzymatic effects.

A maghemite (γ-Fe2O3) incorporated activated carbon photocatalytic nanocomposite fabricated via Co-precipitation utilized against degradation of methyl orange

The γ−Fe2O3/ACP has been synthesized in different ratios by facile co-precipitation method to degrade the methyl orange dye. In order to check the stability and potential of photo activated catalyst, UV, PL, SEM, XRD, EDX, FTIR and Zeta Potential are discussed here. The bandgap has been reduced from 2.06 eV to 1.86eV. Here, 1:3 γ−Fe2O3/ACP sample showed maximum reduced bandgap of 1.86 eV. The PL spectroscopy showed that 1:3 sample has less intensity, which in turn have 94 % photo degradation of methyl orange dye in 180min. The 1:3 sample showed 87 % degradation of methyl blue dye at 125mins light irradiation and proved as an optimal concentration of ACP in maghemite at pH of 11. The inclusion of carbon into maghemite enhances the overall properties by reducing the charge recombination rate. No impurity has been found in the final synthesized samples confirmed through EDX. The XRD and SEM revealed that size of crystallites and particle size increases, which confirms that bandgap is reduced. While trapping techniques and recycling techniques has been employed on the optimal concentration sample to check its stability towards degradation of methyl orange (MO) dye. The photo catalysis through such nanocomposite is not reported before. The 1:3 sample showed promising potential towards pollutants degradation in waste water treatment.

NiFe-Prussian blue analogs catalyst for glucose electrolytic hydrogen production and biomass valorization

Making green hydrogen from natural biomass glucose electrolysis represents a successful win-win scenario which not only achieves energy-efficient hydrogen production but also yields high-value-added chemicals. Herein, we report a NiFe-PBA catalyst synthesized by a facile co-precipitation method for glucose electrooxidation reaction (GOR). Benefiting from the unique ligand structure and the optimal electron, the Ni1·6Fe-PBA achieves a current density of 50 mA cm⁻2 at a potential of only 1.42 V versus Reversible Hydrogen Electrode (RHE), and it maintains potential stability for 50 h. Through an intermittent multipotential-step method it was known that NiOOH is the active site of GOR. Based on the superior GOR activity of this catalyst, we constructed a two-electrode glucose electrolysis hydrogen making system. At a current density of 50 mA cm⁻2, this system reduced the voltage of 230 mV compared to traditional water electrolysis. This improvement significantly reduces energy consumption, requiring only 43.4 kWh to produce 1 kg of H2, saving 6.1 kWh of energy power. To our excitement, we analyzed the electrolyte after stability measurement and found the production of GRA, an important platform molecule for chemical industry and medical treatment. This research provides a promising and sustainable approach for efficient hydrogen production and the value-up of biomass feed-stock.

Effects of Temperature and Precursor Concentration on the Morphological and Optical Properties of Iron Oxide Nanoparticles

Iron oxide nanoparticles are inexpensive materials that are environmentally friendly and have properties that render them suitable for wide range of applications. A facile and time-effective coprecipitation method was used to prepare iron oxide nanoparticles in a 1:1 molar ratio of Fe2+ and Fe3+ ions in solution. Iron oxide nanoparticles obtained at 18 and 60 °C yielded spherical magnetite nanoparticles with particle sizes of 7.63 and 8.5 nm respectively while comprising a mixture of magnetite and hematite nanorods, with a mean width of 9.5 nm and a mean length of 75 nm were obtained at 90 °C. Iron oxide nanoparticles synthesized at 18 °C have energy band gap of 4.16 eV while those synthesized at 60 and 90 °C have the same band gap of 4.66 eV. Precursor concentrations of 0.042, 0.08 and 0.0126 M yielded spherical magnetite nanoparticles with particle sizes of 7.94, 8.5 and 8.5 nm respectively and the particle size range increased with increasing concentration. Magnetite nanoparticles synthesized with concentrations of 0.042, 0.08 and 0.126 M have optical band gaps of 4.65, 4.88 and 5.19 eV respectively. The magnetite crystalline phase was produced regardless of concentration at temperatures of 18 and 60 °C while a temperature of 90 °C yielded a mixture of magnetite and hematite phases. The band optical band gap showed direct proportionality with temperature and concentration in an inert environment.

Fast, One‐Step In Situ Synthesis of a Hierarchical Sn4+‐Doped TiNb2O7 Nanosphere as a High‐Performance Anode Material

AbstractTitanium niobium oxide (TNO) exhibits great potential as a lithium‐ion battery anode due to its high capacity, minimal volume change during cycling, and safe good operation characteristic enabled from its voltage profile. However, its intrinsically low electronic and ionic conductivity hinders its potential for practical applications. This work proposes a facile coprecipitation method to address these limitations by incorporating a nano‐macro structure and in situ Sn ion doping into bulk TNO. This approach ensures homogeneous integration of TNO precursors and the Sn dopant at a molecular level within the co‐precipitation nanoparticles. Additionally, the use of low toxicity solvents facilitate scalability of the synthesis process. Excellent rate capability, high reversible capacities, and good capacity retention are achieved simultaneously due to synergistic effects of the bulk doping, which expands the crystal volume and enhances Li+ diffusion, combined with abundant surface area of the nano‐macro structures. The specific capacity of Sn‐doped TNO nanospheres remains at 180 mAh/g at a high current density of 40 C (1 C=400 mA g−1), which is nearly four times higher than that of undoped samples. Furthermore, the cyclic voltammetry analysis at various scanning rates reveals an increased Li+ diffusion rate in Sn doped titanium niobium dioxide.

Ultrahigh-Resolution Visualization of Vascular Heterogeneity in Brain Tumors via Magnetic Nanoparticles-Enhanced Susceptibility-Weighted Imaging.

The precise assessment of vascular heterogeneity in brain tumors is vital for diagnosing, grading, predicting progression, and guiding treatment decisions. However, currently, there is a significant shortage of high-resolution imaging approaches. Herein, we propose a contrast-enhanced susceptibility-weighted imaging (CE-SWI) utilizing the minimalist dextran-modified Fe3O4 nanoparticles (Dextran@Fe3O4 NPs) for ultrahigh-resolution mapping of vasculature in brain tumors. The Dextran@Fe3O4 NPs are prepared via a facile coprecipitation method under room temperature, and exhibit small hydrodynamic size (28 nm), good solubility, excellent biocompatibility, and high transverse relaxivity (r2*, 159.7 mM-1 s-1) under 9.4 T magnetic field. The Dextran@Fe3O4 NPs-enhanced SWI can increase the contrast-to-noise ratio (CNR) of cerebral vessels to 2.5 times that before injection and achieves ultrahigh-spatial-resolution visualization of microvessels as small as 0.1 mm in diameter. This advanced imaging capability not only allows for the detailed mapping of both enlarged peritumoral drainage vessels and the intratumoral microvessels, but also facilitates the sensitive imaging detection of vascular permeability deterioration in a C6 cells-bearing rat glioblastoma model. Our proposed Dextran@Fe3O4 NPs-enhanced SWI provides a powerful imaging technique with great clinical translation potential for the precise theranostics of brain tumors.

Interface engineering based NiCoMoO4/Ti3C2Tx MXene heterostructure for high-performance flexible supercapacitors

The advancement of interface engineering has demonstrated remarkable efficacy in overcoming the primary impediment associated with sluggish reaction kinetics in supercapacitor electrodes. In this investigation, we employed a facile co-precipitation method to synthesize NiCoMoO4/MXene heterostructures utilizing Ti3C2Tx MXene nanosheets as carriers. This heterostructure inhibits the restacking of MXene nanosheets and simultaneously enhances the exposure of electrochemically active sites in NiCoMoO4 nanorods, thereby mitigating the reduction in specific capacitance resulting from volumetric fluctuations. The NiCoMoO4/MXene electrode, possessing pseudo-capacitance properties, demonstrates an impressive level of specific capacitance, exceptional performance across various charging rates, and consistent behavior throughout repeated cycles. By optimizing the mass ratio, this electrode achieves a specific capacity of 1900 F/g under a current density of 1 A/g. Even after enduring 10,000 cycles at a significantly higher current density of 5 A/g, it still maintains an impressive retention rate of 94.73 %. Our density functional theory (DFT) calculations indicate that the enhanced electrochemical performance can be attributed to the improved electronic coupling within the NiCoMoO4/MXene heterostructure. The integration of NiCoMoO4/MXene cathode and activated carbon (AC) anode with an alkaline gel electrolyte containing potassium ferricyanide in flexible quasi-solid-state supercapacitors (FSSCs) results in exceptional electrochemical performance and flexibility. These FSSCs demonstrate a maximum energy density of 72.89 Wh kg−1 at a power density of 850 W kg−1, while maintaining an impressive power output of 16,780 W kg−1 with an energy density of 37.28 Wh kg−1. Based on these outstanding properties, it is evident that the NiCoMoO4/MXene heterojunction possesses significant advantages as electrode material for supercapacitors, and the fabricated FSSCs devices pave a new pathway for flexible electronic devices.

Exploring the Phase Transformation of Tri-Metallic Prussian Blue Analogue Pre-Catalyst for Improved Oxygen Evolution Reaction

The development of non-noble metal electrocatalyst with high-efficiency and clear underlying of the related reaction mechanism towards the sluggish oxygen evolution reaction (OER) is critical for large-scale hydrogen production. In this study, tri-metallic Prussian blue analogue (PBA) of FeCoNi-PBA was synthesized using a facile and low-energy consumption co-precipitation method. The FeCoNi-PBA was found to be etched by the high-pH 1 M KOH electrolyte such that under anodic applied potential during electrolysis the formation of metal (oxy)hydroxide is accelerated. Operando Raman and post-mortem characterizations reveal that the applied anodic potential promotes the phase transformation so that the PBA undergoes self-reconstruction to form metal (oxy)hydroxide embedded in a carbon matrix with fully exposed active sites. The metal (oxy)hydroxide serves as the real active sites while the carbon matrix is believed to enhance the conductivity and hydrophilicity, which facilitates the electron transfer and electrolyte diffusion to improve the OER performance. In alkaline media, FeCoNi-PBA demonstrates excellent OER performance with a low overpotential of 236 mV at 10 mA cm−2, small Tafel slope of 43.8 mV dec-1, and long-term durability.

Interface engineering strategy in bimetallic carbide and cobalt nanoparticles encapsulated in N-doped carbon nanotubes for excellent microwave absorption

In this paper, bimetallic Zn/Co zeolitic imidazole frameworks (Zn/Co-ZIFs) with various Zn/Co ratios have been successfully synthesized via a facile coprecipitation method, and then were converted into a series of N-doped bamboo-like carbon nanotubes (CNTs) encapsulated in Co nanoparticles with the aid of dicyandiamide after an annealing process. Results show that when the Zn/Co ratios in the Zn/Co-ZIF are 2:1 and 1:2, the morphology of ZIFs is hexagonal-star-like shape while it presents rod-like shape at the Zn/Co ratio of 1:1. The corresponding derivatives of these ZIFs after carbonization are identified as Co3ZnC/Co@CNTs, Co@CNTs-12, and Co@CNTs-11, and their microwave absorption performances are investigated at the same time. Among these as-synthesized composites, Co3ZnC/Co@CNTs exhibits the best microwave absorption behavior with a minimum reflection loss (RLmin) of −65.34 dB and an effective absorption bandwidth (EAB) of 5.35 GHz at a low filler content of 15 wt% and a thickness of 2.2 mm. Moreover, using CST to analyze Co3ZnC/Co@CNTs the radar cross section (RCS) was simulated, and the reduction value of RCS was −31.95 dB m2, and effective absorption can achieve full angle coverage. The outstanding microwave absorption capabilities of Co3ZnC/Co@CNTs can be credited to the effective impedance matching, robust interface polarization, and significant conduction loss. This paper also provides a strategy for strengthening the microwave absorption ability of absorbers through the interface engineering.

Nanostructured Iron (III)-Copper (II) Binary Oxide as a Highly Efficient Magnetically Recoverable Nanocatalyst for Facile One-pot Synthesis of 2, 4, 5-trisubstituted Imidazole and 1, 4-dihydro Pyridine Derivatives under Solvent-free Conditions

Abstract: The Fe (III)-Cu (II) binary oxide magnetic nanocatalyst emerges as an environmentally friendly and highly efficient solid acid catalyst, demonstrating remarkable utility in the one-pot synthesis of 2, 4, 5-trisubstituted imidazole and 1,4-dihydropyridine compounds, all achieved under solvent-free conditions. A facile co-precipitation method was used to synthesize nanostructured Fe-Cu binary oxide. Notably, this Fe-Cu binary oxide magnetic nanocatalyst proves its eco-friendly credentials as an exceptionally efficient and reusable catalyst, offering ease of handling, recovery, and multiple uses with minimal reactivity loss. Furthermore, the Fe (III)-Cu (II) binary oxide magnetic nanocatalyst's magnetic separability enhances its practicality, allowing for effortless catalyst retrieval after reactions. Significantly, the structural characteristics are meticulously elucidated through advanced analytical techniques, including 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. This work presents a versatile and sustainable solution for catalysis, with wide-reaching implications for green chemistry and the development of reusable, efficient catalysts for organic synthesis. The exceptional performance and eco-friendliness of the Fe-Cu binary oxide magnetic nanocatalyst underscore its practical significance. Fe-Cu binary oxide magnetic nanocatalyst exhibits the highest catalytic activity compared to others. The employment of this catalyst consistently delivers excellent yields in the target reactions, highlighting its potential to contribute positively to sustainable chemical processes.

A S-scheme 0D/2D heterojunction formed by decorating Cd0.5Zn0.5S nanoparticles on Cu2MoS4 plates for efficient photocatalytic hydrogen generation

Rationally designing a Step-scheme (S-scheme) hetero-structured photocatalyst with high redox capability and separation efficiency of photoinduced carriers is considered as an attractive approach to address the shortcomings of single component and traditional hetero-structured photocatalyst. Herein, enlightened by the predictions of density functional theory (DFT), a unique S-scheme heterojunction photocatalyst was successfully fabricated by incorporating zero-dimensional (0D) Cd0.5Zn0.5S (CZS) on two-dimensional (2D) lamellar Cu2MoS4 (CMS) plates via a facile coprecipitation method, which substantially enhances the photocatalytic activity for hydrogen (H2) generation. CZS nanoparticles deposited on the surface of CMS nanoplates play a crucial role in creating highly intimate heterojunction interfaces and abundant exposed reaction sites, laying the foundation for improved photocatalytic performance. Furthermore, the significant difference in Fermi levels and band structures between CZS and CMS result in the formation of the internal electric field (IEF) and energy band bending at the interface of the heterojunction. This S-scheme charge transfer path enables 0D/2D CZS/CMS heterojunction possesses an exceptional capacity to maintain the robust redox potential and boosts the separation efficiency of light-induced carriers, as verified by DFT calculations and energy band structure analyses. As expected, the optimal heterojunction exhibits a satisfactory H2 generation rate of 13.1 mmol·g-1·h−1, which is nearly 7.7-fold higher than that of individual CZS. This study is expected to inspire the design of morphology-controlled hetero-structured photocatalyst with S-scheme charge transfer route for photocatalytic H2 generation.

Magnetically recoverable CuFe2O4 nanocatalyst: Dual catalytic action in sonogashira and Chan-Lam coupling reactions

Magnetically retrievable CuFe2O4 nanocatalyst has been synthesized for Sonogashira (C-C) and Chan-Lam (C-N) coupling reactions by a facile co-precipitation method. Synthesized nanocatalyst was characterized by powder x-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analysis. The catalytic action of the catalyst was evaluated for both Pd-free C-C coupling and base-free C-N coupling reactions where an excellent product yield up to 96 % and 95 % respectively was obtained. The uniqueness of the catalyst was its effective performance under ambient reaction conditions in green solvents such as EtOH and EtOH:H2O (1:1) with a broad substrate scope. The catalyst can be easily retrieved from the reaction mixture with the aid of an external magnet and reused at least five times without significant loss in catalytic activity. The structural stability of the recovered catalyst was confirmed by XRD, FTIR, SEM and ICP-OES (Inductively coupled plasma - optical emission spectrometry) analysis. Thus, the synthesized catalyst works excellently well for dual applications and establishes the sustainable application of the catalyst.

Highly pure hydrogen production via the thermocatalytic decomposition of methane over Ni/SiO2.MgO catalysts: Impact of the catalyst's chemical composition

The goal of current research is to focus on exploring the effects of various MgO/SiO2 ratios, emphasizing their impact on the structure properties and advancing the catalytic activity and the chemical life span of Ni-catalysts by an exciting mixture of SiO2 and MgO to generate COx-bare hydrogen and nanocarbon simultaneously from methane decomposition reactions. SiO2/MgO mixed oxides with different ratios (0.5, 1, and 2) were ready via a facile co-precipitation method from magnesium nitrate and sodium metasilicate and used as supports for various nickel contents (30, 40, 50, and 60 wt%) followed by an impregnation technique. Different analytical techniques, such as XRD, BET, SEM, EDS, H2-TPR, and TPO, were used to characterize the catalysts before and after the catalytic runs. The prepared catalysts with various SiO2/MgO molar ratios depicted the BET surface area limiting from 37.9 to 143.4 m2 g−1, indicating remarkable surface improvements. The vast CH4 conversion of 64 % earned on the 50 wt% Ni/SiO2·MgO at 575 °C. Moreover, lower deactivation was detected regarding this catalyst at 600 min on stream.