Continuous synthesis of metal oxide‐supported high‐entropy alloy nanoparticles with remarkable durability and catalytic activity in the hydrogen reduction reaction

Metal oxide‐supported multielement alloy nanoparticles are very promising as highly efficient and cost‐effective catalysts with a virtually unlimited compositional space. However, controllable synthesis of ultrasmall multielement alloy nanoparticles (us‐MEA‐NPs) supported on porous metal oxides with a homogeneous elemental distribution and good catalytic stability during long‐term operation is extremely challenging due to their oxidation and strong immiscibility. As a proof of concept that such synthesis can be realized, this work presents a general “bottom‐up” l ultrasonic‐assisted, simultaneous electro‐oxidation–reduction‐precipitation strategy for alloying dissimilar elements into single NPs on a porous support. One characteristic of this technique is uniform mixing, which results from simultaneous rapid thermal decomposition and reduction and leads to multielement liquid droplet solidification without aggregation. This process was achieved through a synergistic combination of enhanced electrochemical and plasma‐chemical phenomena at the metal–electrolyte interface (electron energy of 0.3–1.38 eV at a peak temperature of 3000 K reached within seconds at a rate of ~105 K per second) in an aqueous solution under an ultrasonic field (40 kHz). Illustrating the effectiveness of this approach, the CuAgNiFeCoRuMn@MgO‐P3000 catalyst exhibited exceptional catalytic efficiency in selective hydrogenation of nitro compounds, with over 99% chemoselectivity and nearly 100% conversion within 60 s and no decrease in catalytic activity even after 40 cycles (>98% conversion in 120 s). Our results provide an effective, transferable method for rationally designing supported MEA‐NP catalysts at the atomic level and pave the way for a wide variety of catalytic reactions. imag

Synthesis and characterization of Turbinaria ornata mediated Zn/ZnO green nanoparticles as potential antioxidant and anti-diabetic agent of enhanced activity

Turbinaria ornata marine macro-algae (TUN) have been applied as carriers for the metallic zinc/ZnO blended nanoparticles, which were synthesized by implementing the extracted phytochemicals of the algae. The resulting hybrid bio-composite (Zn@ZnO/TUN) was characterized as a potential product of promising antioxidant and antidiabetic characteristics in synergetic studies. The obtained composite demonstrate t6he existing or complex biological active groups related to zinc (Zn-O stretching and tetrahedral Zn coordination) and organic groups (amino, methyl, carboxylic, alkynes, P=O, C–C–O, C=N, and N–O) corresponding to the extracted phytochemicals of algae (polysaccharides, phospholipids, lipids, fucose, and phosphodiester). The assessment of Zn@ZnO/TUN hybrid as an anti-oxidant agent validated excellent effectiveness towards the commonly examined radicals (DPPH (88.2 ± 1.44%), nitric oxide (92.7 ± 1.71%), ABTS (90.5 ± 1.8%), and O2●− (30.6 ± 1.32%), considering the determined performance for the commercially used standard (ascorbic acid). Regarding the antidiabetic properties, the incorporation of Zn@ZnO/TUN inhibits the function and activities of the key oxidizing enzymes, either the commercial forms (α-amylase (88.7 ± 1.3%), α-glucosidase (98.4 ± 1.3%), and amyloglucosidase (97.3 ± 1.4%) or the crude intestinal active forms (α-amylase (66.2 ± 1.4%) and α-glucosidase (95.1 ± 1.5%). This inhibitory effectiveness of Zn@ZnO/TUN is significantly better than the measured performances using commercialized miglitol drugs and slightly better than acarbose. Considering the expense and adverse effects of conventional medications, the synthesized Zn@ZnO/TUN blend could be evaluated as a marketable antidiabetic and antioxidant medication. The findings also demonstrate the influence of the derived phytochemicals from Turbinaria ornata and the incorporation of its algae residuals as carriers for the metal nanoparticles on the biological function of the composite. The cytotoxicity investigation reflected safety effect of the composite on colorectal fibroblast cells (CCD-18Co) (96.3% cell viability) and inhibition effect on cancerous colorectal cells (HCT-116) (47.3% cell viability)

Solvent extraction of chromium and copper using Schiff base derived from terephthaldialdehyde and 5-amino-2-methoxy-phenol

Separation with solvent extraction of Cu2+ and Cr3+ from aqueous solution using [N,N′-p-phenylene bis (5-amino-2-methyoxy-phenol)] as the new extractant has been studied. The Schiff base was synthesized by reaction of terephthaldialdehyde and 5-amino-2-methoxy-phenol. Schiff base has been characterized by elemental analyses, mass and IR spectral data. The Schiff base has been studied by liquid–liquid extraction toward the metal ions (UO22+) and d-metal ions (Hg2+, Cu2+ and Cr3+) from aqueous phase to organic phase. The effect of chloroform and nitrobenzene as organic solvents on the metal chlorides extraction was investigated at 25 ± 0.1 °C by using flame atomic absorption. It observed that extraction percentages not effect with the change of diluents. It was found that the extraction efficiency of ligand for metals is in the order Cu2+ > Cr3+. The results show that metals ions of U3+ and Hg2+ are not extracted by Schiff base (E < 1%). The extractability and selectivity of cations was evaluated as a function of relationship between distribution ratios of metal and pH. Cu2+ showed the highest extractability and selectivity at pH 6.27. The effect of ionic strength and aqueous to organic phase on the extraction has been studied

Improving the Electrochemical Performance of Zinc Sulfides by Iron Doping Toward Supercapacitor Applications

Abstract The rational design of heterostructured Fe‐doped ZnS microspheres (FeZnS‐MS) and their use as electrode materials for supercapacitors (SCs) is proposed. FeZnS‐MS are mounted on a Ni foam substrate to develop high‐activity positive electrodes for SCs. The morphological and electrochemical performances of the hydrothermally synthesized FeZnS‐MS are investigated, revealing the formation of microspherical Fe‐doped ZnS nanocubes. Different Fe ratios (0.1, 0.2, and 0.3) are successfully introduced to ZnS without impurities, whereas two phases are produced when the percentage is increased to 0.4. Notably, under a current density of 2 A g−1, the Zn0.7Fe0.3S nanocomposite showed an exceptional specific capacitance of 575 F g−1, compared to the moderate value (200 F g−1) achieved by ZnS. At 0.5 and 1 A g−1, the Zn0.7Fe0.3S electrode presented an even better specific capacitance of 700 and 604.5 F g−1, respectively. Using this electrode, a hybrid supercapacitor system is developed and delivered 11 Wh kg−1 and a high specific power of 591.2 W kg−1

Hybrid Organic-Inorganic Materials on Metallic Surfaces: Fabrication and Electrochemical Performance

In recent years, hybrid organic-inorganic (HOI) materials have attracted massive attention as they combine the unique properties of organic and inorganic compounds. In this review, we focus on the formation of HOI materials and their electrochemical performance that can be controlled by microstructural design depending upon their chemical composition. This overview outlines the recent strategies of preparing HOI materials on metallic surface via wet-electrochemical systems, such as plasma electrolysis (PE) and dip chemical coating (DCC). The corresponding electrochemical behavior for short and long term exposures is also summarized

Enhanced Retention of Cd(II) by Exfoliated Bentonite and Its Methoxy Form: Steric and Energetic Studies

Synergistic studies were conducted to evaluate the retention potentiality of exfoliating bentonite (EXBEN) as well as its methanol hybridization derivative (Mth/EXBEN) toward Cd(II) ions to be able to verify the effects of the transformation processes. The adsorption characteristics were established by considering the steric and energetic aspects of the implemented advanced equilibrium simulation, specifically the monolayer model with a single energy level. Throughout the full saturation states, the adsorption characteristics of Cd(II) increased substantially to 363.7 mg/g following the methanol hybridized treatment in comparison to EXBEN (293.2 mg/g) as well as raw bentonite (BEN) (187.3 mg/g). The steric analysis indicated a significant rise in the levels of the active sites following the exfoliation procedure [retention site density (Nm) = 162.96 mg/g] and the chemical modification with methanol [retention site density (Nm) = 157.1 mg/g]. These findings clarify the improvement in the potential of Mth/EXBEN to eliminate Cd(II). Furthermore, each open site of Mth/EXBEN has the capacity to bind approximately three ions of Cd(II) in a vertically aligned manner. The energetic investigations, encompassing the Gaussian energy (less than 8 kJ/mol) plus the adsorption energy (less than 40 kJ/mol), provide evidence of the physical sequestration of Cd(II). This process may involve the collaborative impacts of dipole binding forces (ranging from 2 to 29 kJ/mol) and hydrogen binding (less than 30 kJ/mol). The measurable thermodynamic functions, particularly entropy, internal energy, and free enthalpy, corroborate the exothermic and spontaneous nature of Cd(II) retention by Mth/EXBEN, as opposed to those by EXBEN and BE

Origin of the synergistic effects of bimetallic nanoparticles coupled with a metal oxide heterostructure for accelerating catalytic performance

Precisely tuning bicomponent intimacy during reactions by traditional methods remains a formidable challenge in the fabrication of highly active and stable catalysts because of the difficulty in constructing well‐defined catalytic systems and the occurrence of agglomeration during assembly. To overcome these limitations, a PtRuPNiO@TiO x catalyst on a Ti plate was prepared by ultrasound‐assisted low‐voltage plasma electrolysis. This method involves the oxidation of pure Ti metal and co‐reduction of strong metals at 3000°C, followed by sonochemical ultrasonication under ambient conditions in an aqueous solution. The intimacy of the bimetals in PtRuPNiO@TiO x is tuned, and the metal nanoparticles are uniformly distributed on the porous titania coating via strong metal‒support interactions by leveraging the instantaneous high‐energy input from the plasma discharge and ultrasonic irradiation. The intimacy of PtRuPNiO@TiO x increases the electron density on the Pt surface. Consequently, the paired sites exhibit a high hydrogen evolution reaction activity (an overpotential of 220 mV at a current density of 10 mA cm−2 and Tafel slope of 186 mV dec−1), excellent activity in the hydrogenation of 4‐nitrophenol with a robust stability for up to 20 cycles, and the ability to contrast stated catalysts without ultrasonication and plasma electrolysis. This study facilitates industrially important reactions through synergistic chemical interactions

Experimental and theoretical investigation of high-entropy-alloy/support as a catalyst for reduction reactions.

Control of chemical composition and incorporation of multiple metallic elements into a single metal nanoparticle (NP) in an alloyed or a phase-segregated state hold potential scientific merit; however, developing libraries of such structures using effective strategies is challenging owing to the thermodynamic immiscibility of repelling constituent metallic elements. Herein, we present a one-pot interfacial plasma–discharge-driven (IP-D) synthesis strategy for fabricating stable high-entropy-alloy (HEA) NPs exhibiting ultrasmall size on a porous support surface. Accordingly, an electric field was applied for 120 s to enhance the incorporation of multiple metallic elements (i.e., CuAgFe, CuAgNi, and CuAgNiFe) into ally HEA-NPs. Further, NPs were attached to a porous magnesium oxide surface via rapid cooling. With solar light as the sole energy input, the CuAgNiFe catalyst was investigated as a reusable and sustainable material exhibiting excellent catalytic performance (100% conversion and 99% selectivity within 1 min for a hydrogenation reaction) and consistent activity even after 20 cycles for a reduction reaction, considerably outperforming the majority of the conventional photocatalysts. Thus, the proposed strategy establishes a novel method for designing and synthesizing highly efficient and stable catalysts for the convertion of nitroarenes to anilines via chemical reduction