Trimetallic Nanoparticles Research Articles

Magnetically Induced Amination of Alcohols Using MNi@Cu (M=Fe, Co) Nanoparticles as Catalysts

AbstractThe synthesis of tertiary amines from alcohols (i.e. heptanol, dodecanol, cyclohexanol, benzylalcohol) and secondary amines (Me2NH (DMA), nPr2NH, nBu2NH) has been achieved in one step using trimetallic nanoparticles (NPs) displaying a magnetic core (Co4Ni6 and Fe3Ni7) and a Cu shell as both catalysts and heating agent in the presence of an alternating magnetic field. This methodology limits the redistribution reactions occurring on amines at high temperature leading to both much higher conversion and selectivity in the absence of solvent than usually observed using conventional heating. Moreover, Co4Ni6@Cu NPs were found moisture resistant, thereby allowing for performing the reaction with commercial DMA in water (40 % wt) with again high conversion and selectivity.

Antimicrobial, anti-biofouling, antioxidant, and biocompatible fabrics with high durability via green growth of trimetallic nanoparticles

There is a high demand for green and sustainable multifunctional fabrics, which find application in a variety of real-life contexts. This study addresses the development of antimicrobial, antioxidant, anti-biofouling and biocompatible fabrics through a one-step, versatile and cost-effective in-situ green growth strategy. Monometallic, bimetallic and trimetallic nanoparticles comprising silver (Ag), copper (Cu) and zinc (Zn) were grown in-situ on fabric surfaces using Sideritis scardica extract. The average size of nanoparticles was 99 ± 25 nm, 131 ± 29 nm, 68 ± 18 nm for Ag, Cu and Zn. The metallic nanoparticles grown on the fabric surface imparted a range of colors to the fabrics, including yellow, brownish and greenish hues. Nanoparticle-decorated fabrics have antimicrobial, antioxidant, anti-biofouling, biocompatibility, and high durability properties. The decoration of fabrics with metallic nanoparticles mediated antimicrobial properties against bacteria (E. coli and S. aureus) and fungi (C. albicans), achieving a reduction of over 99.99 % (Logarithmic reduction>4). Bimetallic and trimetallic Ag and Cu nanoparticles exhibited enhanced antifungal activity in comparison to their monometallic counterparts. The cytotoxic effects of Cu were effectively eliminated through the fabrication of bimetallic nanostructures containing Zn. Notably, the biocompatibility of monometallic and bimetallic combinations involving Ag and Zn exceeded 95 %. The water contact angles of the decorated fabrics ranged from 145° to 153°. The superhydrophobic character of the fabrics prevented pathogen adhesion and inhibited biofilm formation. Moreover, all nanoparticle-decorated fabrics demonstrated antioxidant properties, with radical-scavenging activity ranging from 46 % to 91 %. The fabrics retained their antimicrobial properties against mechanical abrasion, heating and repeated cycles of washing and bending.

Investigation of the catalytic activity of trimetallic CuAgAu aerogels for the electrochemical reduction of CO<sub>2</sub> to CO

Given the growing demand for efficient catalysts in sustainable energy applications, this study investigates the structural characterization and catalytic activity of CuAgAu trimetallic aerogels synthesized via a sol-gel method. Transmission electron microscopy (TEM) revealed a porous network structure with uniformly dispersed trimetallic nanoparticles averaging 5-10 nm in size, which indicates a successful synthesis and nanostructure formation. X-ray diffraction analysis confirmed the formation of a face-centered cubic structure, with distinct diffraction peaks observed at positions corresponding to the (111), (200), and (220) planes of Cu, Ag, and Au, respectively. These structural features are critical for understanding the crystalline nature and stability of the aerogels. The catalytic activity of CuAgAu aerogels for CO2 reduction was evaluated using linear sweep voltammetry, which showed notable enhancements in current densities at various applied potentials relative to the reversible hydrogen electrode. These findings indicate the aerogels’ effectiveness as catalysts for CO2 conversion. Furthermore, Faradaic efficiency measurements revealed a high selectivity in the conversion of CO2 to CO, achieving a high Faradaic efficiency of 85%, which suggests that the aerogels’ capability to efficiently utilize electrons in producing CO, as a valuable precursor in renewable energy and chemical synthesis applications. The combination of structural integrity, catalytic performance, and high selectivity positions CuAgAu aerogels as promising approach for sustainable energy technologies.

Improved the Sensitivity and Limit of Detection of Surface Alloying SERS Sensors by Controlling Mixing Ratio of Trimetallic (Ag-Au-Pd) Nanoparticles

In this study, three different types of hybrid structures SERS sensors made from different mixing ratio of trimetallic (Ag-Au-Pd) nanoparticles of [Au1: Ag1: Pd1] , [Au1: Ag2: Pd1] , [Au1: Ag2: Pd2] in surface alloying forms deposited on macro porous silicon (macroPsi) layer were created and extensively tested. By using a simple and fast immersion process, trimetallic (Ag-Au-Pd) nanoparticles were created utilizing ion reduction of numerous metallic salts on a macro porous silicon (macroPsi) layer. The macroPsi layers were created using a laser assisted etching (LAE) technique for 15 minutes with a constant density of approximately (28mA/c.m2). At a constant concentration (10-3 M) of HAu.Cl4, Ag.NO3 and Pd.Cl2 to synthesize Au-NPs, Ag-NPs and Pd-NPs, immersion processes with various mixing ratios were performed. The hybrid structures of SERS sensors were examined using XRD, FE-SEM, and Raman microscopes. The sensors were tested at different concentrations from 10-6 to 10-12 of MB target molecules. The SERS trimetallic sensors demonstrated a considerable reliance on hot spot zones among trimetallic nanoparticles. Higher enhancement factor with lower detection limit of Raman signal was obtained from [Au1: Ag2: Pd2] hybrid structures SERS sensor of about 1.5×1010 and 10-14 respectively, due to extra ordinary specific surface area and high surface density forming trimetallic nanoparticles . The variations of mixing ratio of trimetallic (Ag-Au-Pd) provide an effective pathway to develop the sensors performance towards detection of lower concentrations.

Reshaping Immunosuppressive Tumor Microenvironment Using Ferroptosis/Cuproptosis Nanosensitizers for Enhanced Radioimmunotherapy

AbstractRadiotherapy, a traditional cancer treatment, not only controls local tumor growth but also potentially induces immunogenic cell death, initiating systemic immune responses. However, radiotherapy resistance and immunosuppressive tumor microenvironments often limit the potency of radiation‐induced anti‐tumor immune responses, rendering them insufficient for clinical applications. Consequently, trimetallic nanoparticles are constructed with dual enzymatic activity, AuBiCu‐distearoyl phosphoethanolamine‐PEG nanoparticles (AuBiCu‐PEG NPs), to synergistically improve radiotherapy resistance through X‐ray deposition, hypoxia alleviation, and ferroptosis and cuproptosis induction. This approach promotes radiotherapy‐induced immunogenic cell death and boosts anti‐tumor immune responses. Furthermore, AuBiCu‐PEG NPs effectively reversed radiation‐induced upregulation of programmed cell death 1 ligand 1 (PD‐L1), inhibit tumor immune evasion, and reshaped the immune microenvironment. Non‐invasive and real‐time longitudinal monitoring of nanoparticle accumulation in tumors can be achieved using spectral computed tomography (CT) and photoacoustic (PA) imaging. In summary, the designed AuBiCu‐PEG NPs serve as promising nanoplatforms for immune microenvironment remodeling and can be used in multimodal molecular imaging‐guided ferroptosis‐cuproptosis‐enhanced radiotherapy.

Pt–Ni–Co trimetallic nanoparticles anchored on graphene oxide: An effective catalyst for ammonia-borane hydrolysis and direct electrooxidation of ammonia-borane in alkaline solution

In this study, graphene oxide supported platin, nickel and cobalt trimetallic nanoparticles (PtNiCo@GO) were prepared by the impregnation/reduction method. The catalytic performances of PtNiCo@GO catalysts prepared with different atomic ratios were investigated for hydrogen production and electro-oxidation of ammonia-borane (AB). For hydrolysis of ammonia-borane, Pt0.8Ni0.1Co0.1@GO catalyst exhibited higher catalytic activity than Pt0.6Ni0.2Co0.2@GO, Pt0.4Ni0.3Co0.3@GO, and Pt0.2Ni0.4Co0.4@GO. The hydrogen generation rate and turnover frequency values were found to be 540 mL min−1g−1 and 42.8 min−1, respectively, in the experiment conducted at 35 °C, 0.5 mmol AB, and 50 mg Pt0.8Ni0.1Co0.1@GO catalyst. The activation parameters (Ea, ΔH#, and ΔS#) in the catalytic hydrolysis of AB were obtained at 42.22 kJ/mol, 31.95 kJ/mol and −114.82 J/(mol × K), respectively. The effects of the PtNiCo@GO catalyst on AB electro-oxidation were made at a scanning rate of 100 mV/s in the potential range of - 1V/+1V against Ag/AgCl, and chronoamperometry measurements were made at constant potentials of - 0.2V, 0.1V and 0.4V. For cyclic voltammetry and chronoamperometry measurements, 5 mM [Fe(CN)6]3/4 (1 M KCl) redox probe and 1 M NaOH + 50 mM AB solution were used.

Enhanced Fecal Norovirus Detection Using Magneto-Nanocatalys-Based Immunoassay.

A new method has been developed to improve the detection of norovirus (NoV) in complex fecal samples using nanocatalyst-based immunoassays. The method involves using multifunctional trimetallic nanoparticles, known as Ag@Fe3O4@Au NPs. These nanoparticles consist of a core of silver (Ag) and a shell of iron oxide (Fe3O4) decorated with isolated gold nanoparticles (Au NPs). The nanoparticles have enhanced catalytic activity, making them an ideal nanocatalyst for reducing 4-nitrophenol (4-NP, yellow) to 4-aminophenol (4-AP, colorless). The developed Ag@Fe3O4@Au NPs-based immunoassay achieved a limit of detection (LOD) of 1.9 pg/mL for norovirus-like particles (NoV-LP) and 6.97 RNA copy number/mL for fecal NoV. In fecal sample analysis for NoV, a heat treatment at 65°C was necessary to prevent degradation of the target protein, ensuring sensitive detection. This work successfully combined multifunctional nanocatalysts for advanced immunoassays, which could contribute to developing nano-biosensing platforms.

Trimetallic alloy nanoparticles as cocatalyst for improving the photocatalytic performance of graphitic carbon nitride for H2 production

Trimetallic alloy nanoparticles (NPs) hybridized with graphitic carbon nitride (g-C3N4) nanosheets show potential as photocatalysts owing to their multicomponent interactions, increased catalytic efficiency, and enhanced stability. Herein, a NiCoAg–CN nanocomposite comprising NiCoAg alloy NPs deposited on g-C3N4 nanosheets was synthesized via photoreduction using simulated solar light. X-ray photoelectron spectroscopy revealed the metallic properties of Ni, Co, and Ag within the NiCoAg–CN nanocomposite, and the high-resolution transmission electron microscopy image showed alloy NPs on the surface of g-C3N4. The as-formed Schottky junction accelerated the separation and transfer of photoinduced charge carriers in NiCoAg–CN. NiCoAg–CN exhibited a remarkable photocatalytic hydrogen (H2) yield of 4896 μmol/g, surpassing the performance of NiAg–CN and CoAg–CN by 1.9- and 1.8-fold, respectively. This is attributed to the enhanced catalytically active sites, facilitating rapid charge carrier transfer between the NiCoAg alloy and the g-C3N4 nanosheets. Photoluminescence spectra indicated that NiCoAg NPs served as efficient electron conduits, suppressing charge carrier recombination and promoting direct electron transfer. Alloy NPs synthesized via the proposed strategy efficiently harness solar radiation, facilitate charge carrier transfer, and mitigate recombination, thus advancing efficient photocatalytic H2 generation.

Improving biogas production with application of trimetallic nanoparticle using response surface methods

The potential of trimetallic nanoparticles (TMNPs) to enhance biogas production through microbe-to-microbe interactions and boost biogas yield is evident. This present study employed the central composite design (CCD) of response surface methods (RSM) to determine the optimal conditions of iron-cobalt-zinc TMNPs influenced anaerobic digestion for higher biogas yield. The impact of initial pH (6.6–7.4), TMNPs concentration (0–30 mg L−1), temperature (25-45 °C), and hydraulic retention time (HRT) (0-4 days) were modelled for improved biogas production. The results indicated that the linear model terms of pH and TMNPs concentration, and quadratic model terms of temperature and HRT, significantly affect the biogas production. Linear model terms of TMNPs, temperature, pH, and HRT have significant interactive effects and the numerical analysis identified the best conditions for the evaluated parameters. Ideal anaerobic process settings generated a maximum cumulative biogas production of 3700 mL−1POME than blank (2000 mL−1), corresponding to an 85 % yield. Optimizing the initial pH, TMNPs concentration, temperature, and HRT can significantly improve biogas yield and could be helpful for developing more efficient AD processes at large volume and commercial biogas plants. Promoting TMNPs as catalysts positively improves an AD process towards sustainable biogas production.

Magnetically Induced Amination of Alcohols Using MNi@Cu (M=Fe, Co) Nanoparticles as Catalysts.

The synthesis of tertiary amines from alcohols (i.e. heptanol, dodecanol, cyclohexanol, benzylalcohol) and secondary amines (Me2NH (DMA), nPr2NH, nBu2NH) has been achieved in one step using trimetallic nanoparticles (NPs) displaying a magnetic core (Co4Ni6 and Fe3Ni7) and a Cu shell as both catalysts and heating agent in the presence of an alternating magnetic field. This methodology limits the redistribution reactions occurring on amines at high temperature leading to both much higher conversion and selectivity in the absence of solvent than usually observed using conventional heating. Moreover, Co4Ni6@Cu NPs were found moisture resistant, thereby allowing for performing the reaction with commercial DMA in water (40 % wt) with again high conversion and selectivity.

Rotating Disk Slurry Electrodeposition of Trimetallic Nickel-Cobalt-Iron Nanoparticles Electrocatalyst on Vulcan Xc-72R for the Oxygen Reduction Reaction in Alkaline Media

Although platinum and platinum group metals (PGMs) catalysts are the most efficient for oxygen reduction reaction, the cost and scarcity of the metals are the reason to look for alternative electrocatalysts. Transition metals, such as cobalt, iron, and nickel, have shown promise as an alternative catalyst to oxygen reduction reactions (ORR). In this work, we electrochemically synthesized nickel-cobalt-iron trimetallic alloy nanoparticles dispersed on carbon Vulcan using Rotating Disk Slurry Electrodeposition (RoDSE). This technique is an energy-efficient green method to synthesize well-dispersed catalysts on carbon and oxide supports for various applications including the oxygen reduction reaction (ORR) for fuel cell applications. Cobalt-nickel iron nanoparticles have been well dispersed in 20 mg carbon Vulcan XC-72R using a negative potential (-1.05V vs Ag/AgCl-sat KCl) in a saturated Argon environment. The electrodeposition potential was obtained from cyclic voltammetry analysis of the metal salts in 0.1m KClO4 solution with an electrochemically cleaned glassy carbon electrode. The starting material precursors were iron chloride, nickel acetate, and cobalt acetate in 0.1 M KClO4 aqueous solution. A 500 micromolar metal salt solution aliquot was added for the electrodeposition every 20 minutes, with a total of 12 aliquots.Compared with commercially available 20% Pt/Vulcan, the synthesized catalyst shows comparable mass activity and durability with an onset potential of 0.78V vs RHE(@0.01mA/cm2), limiting current density of 5.56mA/cm2 and half wave potential of 0.66V vs RHE.The X-ray diffraction (XRD) studies and transmission electron microscopy showed that trimetallic nanoparticles are formed and deposited on the carbon Vulcan support. Moreover, scanning electron microscopy, X-ray fluorescence studies, and transmission emission microscopy show the presence of trimetallic nanoparticles. The RDE and RRDE studies show that the synthesized material is active and may lead to a good and inexpensive catalyst for ORR.

Removal of crocein orange G from water solutions by trimetallic nanoparticles [Co/Cu/M (M=Ni, Zn)] prepared by chemical reduction method

Co-Cu-Ni and Co-Cu-Zn trimetallic nanoparticles (NPs) were prepared by chemical reduction method which were then used as adsorbent to remove Crocein Orange G dye from solution. The elemental composition of the fabricated NPs was determined by EDX analysis, surface morphology was assessed by SEM, and its crystalline nature was confirmed by XRD analysis. The functional groups on nanoparticles were confirmed by FT-IR analysis. The optimum dosage was found to be 0.01 g. Langmuir model as well as linear pseudo 2nd order kinetics models best explained the obtained data. The maximum adsorption capabilities were found to be around 497.618 mg/g and 683.093 mg/g, respectively for Co-Cu-Ni and Co-Cu-Zn trimetallic NPs. The adsorption process was exothermic, as evidenced from the positive ΔH° values. The negative values of ΔG° at the corresponding temperatures support the spontaneous nature of the adsorption processes. The positive entropy changes (ΔS°) suggested that there is more disorderness at the interface between the solid and the solution during the adsorption. The fabricated trimetallic nanoparticles have effectively adsorbed Crocein Orange G, which may be considered as an attractive option in wastewater treatment and environmental remediation applications due to diversity of metal ions on surface offering differential attractive forces for pollutant.

Enhanced photocatalytic degradation and synergistic effects of Tin-Doped zinc oxide nanoparticles for environmental remediation

Using zinc acetate and sodium hydroxide as starting reagents, zinc oxide nanoparticles (NPs) were constructed using a co-precipitation process. Various metal elements were incorporated into the nanocomposites. The synthesized samples underwent calcination at different temperatures for a duration of 2 h. Characterization of the samples was conducted employing XRD, SEM, EDS, and PIXE analysis. SEM imagery revealed diverse morphological alterations of ZnO after doping. The whole width at half the maximum of the XRD peaks, which indicates sizes in the nano range, was used to calculate the average crystallite sizes of the samples using Debye-Scherer’s formula. EDS analysis confirmed the production of highly pure ZnO nanostructures via this method. The synthesized bimetallic and tri-metallic NPs were utilized for the degradation of hazardous organic dyes, with the degradation process monitored using UV–visible spectroscopy. This study underscores the significance of doped ZnO NPs as effective agents for biodegradation.

Fresh sodium storage of FeCoNi alloys confined in biomass carbon revealed by operando magnetometry

Focusing on the commercialization of sodium ion batteries (SIBs), the biggest challenge is discovering proper anode materials with high availability and safety. Among various materials, alloying metal anodes can achieve high-capacity sodium storage. However, transition metals, such as Fe, Co, Ni, etc. are considered to be inactive alloying with Na. Herein, by introducing trimetallic FeCoNi alloy nanoparticles confined in waste wool-derived carbon based on a sulfhydryl domain-limiting strategy, we synthesize porous N, S co-doped biomass carbon-coated trimetallic FeCoNi alloy composites (FeCoNi@NSC). Surprisingly, the optimal FeCoNi@NSC anode displays superior reversible specific capacities of 439.4 mAh·g−1 at 0.1 A·g−1, and an excellent cycling life of up to1000 cycles at 4 A·g−1, which is similar to that of the current reported tin/antimony/germanium/bismuth-based anodes. Besides the capacity contribution of biomass carbon, the combination of in situ magnetometry, high-resolution transmission electron microscopy and electrochemical impedance characterization techniques reveal that the rising capacity originates from spin-polarized surface capacitance, extra capacity of transition metal oxides, and low-voltage capacity of solid electrolyte interphase, as quantificated by monitoring the variation in magnetism of surface capacitance. This work provides a breakthrough concept for novel anode materials of SIBs choices.

Controlling the composition and nanostructure of Au@Ag–Pt core@multi-shell nanoparticles prepared by co-reduction method

Three types of Au@Ag–Pt core@multi-shell nanoparticles (NPs) were synthesized via a co-reduction reaction from a galvanic replacement reaction (GRR) and a reducing agent, with different feeding ratios of Ag or Pt precursors. The morphology of the core-shell NPs showed a thin multi-shell with a mixture of Ag, void, and Pt granules, and their microstructure was investigated by scanning transmission electron microscopy. The effect of the Ag or Pt precursor feeding ratios on the competition of the two reduction reactions, and the subsequent impact on the nanostructure of Ag-void-Pt multi-shell were discussed. In the case of the sample with a reduced Ag precursor feeding ratio, the thickness of the Ag layer decreased significantly. The oxidation resistance of the Ag layer was improved due to the charge-transfer effect from Au to Ag, which suppressed galvanic replacement, and the reaction by the reducing agent was dominant. In the case of the sample with a reduced Pt precursor feeding ratio, the number of Pt granules was found to decrease while the volume of voids was maintained, suggesting that GRR was the dominant reaction in the co-reduction method. These results provide further insight into the co-reduction reaction mechanism and enable the control of noble trimetallic nanoparticles with complex shells.

Dye degradation activity of biogenically synthesized Cu/Fe/Ag trimetallic nanoparticles

Abstract Over the past few decades, nanotechnology has gained momentum because of its potential to create a safer and healthier living environment using eco-friendly approaches. This study describes a safer, more dependable, and ecologically friendly technique of biologically synthesizing Cu/Fe/Ag trimetallic nanoparticles (NPs) using an aqueous leaf extract of Catharanthus roseus as the reducing and stabilizing agent. The synthesized trimetallic NPs were characterized by scanning electron microscope, Fourier transform infrared, dynamic light scattering, and ultraviolet–visible analysis and were evaluated for their potential applications, which included antioxidant properties and catalytic dye degradation. The result suggests that the antioxidant properties of Cu/Fe/Ag NPs are more significant than those of ascorbic acid, a known antioxidant, at lower doses (10 µg·ml−1) while a higher dose of 1,000 µg·ml−1 gives a 69.81% scavenging activity. The impact of Cu/Fe/Ag trimetallic NPs on the catalytic degradation of hazardous dyes such as phenol red (PR) and eosin yellow (EY) was also studied in this work. For PR and EY, the corresponding percentages of degradation were 76% and 48.6%, respectively.

Antioxidant, dye degradation, and molecular docking studies of orange peel extract derived Ag-Fe-Ni nanoparticles

Nanotechnology has the potential to govern matter at the nanoscale and revolutionise a number of industries, including materials science, hardware, pharmaceuticals, and energy, by facilitating the production of novel materials, technologies, and ideas with exciting properties and uses. This work presents a sustainable process of synthesising Ag-Fe-Ni trimetallic nanoparticles from orange peel extract (Citrus sinensis (L.) Osbeck), which functions as a reducing and capping agent. The nanoparticles were effectively synthesised and characterised using a number of methods, including UV–Vis, Zeta potential, FESEM, EDX, and XRD. The effectiveness of the anti-cancer, catalytic, and antioxidant properties were assessed. Molecular docking was conducted on the synthesised compounds to examine their potential in relation to the complex of ERK2 and catechol. According to the results, the molecules with the least binding energy was 15.55 kcal/mol. Also the synthesied nanoparticles showed increased antioxidant activity and the degradation of methyl red, phenol red, and eosin yellow. Ag-Fe-Ni trimetallic nanoparticles showed antioxidant activity of 89.94 % at 1000 µg/mL. In 60 min, methyl red degraded to 97.67 %. The synthesised compounds have the potential to serve as lead compounds through further optimisation and have anti-cancer activities, as demonstrated by the results of molecular docking study. Thus, Ag-Fe-Ni trimetallic nanoparticles generated from orange peel may serve as a novel antioxidant, catalytic, and anti-cancerous agent.

Triboelectric power generation performance of polyvinyl alcohol using ZnO–CuO–AgO trimetallic nanoparticles

Triboelectric nanogenerators (TENGs), a new technology for gathering sustainable energy, have attracted much scientific interest. In this study, we describe a unique method for modifying the triboelectric power generation performance of Polyvinyl Alcohol (PVA) by adding ZnO–CuO–AgO (ZCA) trimetallic nanoparticles to improve the performance of TENGs and answer the requirement for ecologically benign and biodegradable materials. Hydrothermal synthesis adopted to create ZnO–CuO–AgO trimetallic nanoparticles ensures a distinctive structure with a large surface area, essential for enhancing triboelectric power generation. From the AFM results, it is evident that 1% PVA/ZCA showed the highest output voltage of 0.27V. Despite following the general trend, at higher concentrations of ZCA nanofiller in the PVA matrix, the enhancement of output voltage is not observed, which can be attributed to the non-uniform distribution. The effect of spin-coated film thickness and nanoparticle concentration on the triboelectric performance of the PVA nanogenerator is studied by monitoring the open-circuit voltage in response to various mechanical stimuli. Finally, the developed biodegradable nanogenerators in this study can be used for sustainable energy harvesting applications such as wearable electronics, self-powered sensors, and environmental monitoring systems.

Ultra-High Performance of In Situ Constructed Trimetallic (Pd, Fe, Co) Nanoparticles on Carbon Paper as an Electrocatalyst for Large Current Density Oxygen Evolution Reaction in Alkaline Seawater

Seawater electrocatalysis holds significant promise as a technology for hydrogen production. A simple and low-cost impregnation-hydrothermal and thermal reduction strategy was used to synthesize in situ constructed three-dimensional porous trimetallic (Pd, Fe, and Co) anchored on a cheap and high-conducting carbon paper (CP) electrode for water electrolysis in alkaline media. The fabricated PdFeCo1−xONPs@CP electrode had super-hydrophilic and superaerophobic properties, allowing for the efficient removal of oxygen bubbles from the electrode surface due to the close interaction between the electrode and electrolyte. Furthermore, the synergistic effect of trimetallics and CP-fibers significantly increased OER intrinsic activity. PdFeCo1−xONPs@CP catalyst demonstrated critical low overpotentials of 220 and 300 mV, resulting in an extraordinarily high current density of 100 mA cm−2. For the full cell overall water splitting performance, cell overpotentials as low as 140 and 151 mV were needed to drive 10 mA cm−2 in seawater and alkaline solution electrolytes.

Morphostructural studies of pure and mixed metal oxide nanoparticles of Cu with Ni and Zn

Nano-scale interactions between pure metal or metal-oxide components within an oxide matrix can improve functional performance over basic metal oxides. This study reports on the synthesis of monometallic (CuO), bimetallic (CuO–NiO) and trimetallic (CuO–NiO–ZnO) oxide nanoparticles (NPs) via the co-precipitation method and investigation of morphostructural properties. All of the synthesized metal oxide NPs were calcined at 550 °C temperature and annealed under vacuum. In this work, we applied Scherrer formula, modified Scherrer equation, Williamson-Hall plots, and Halder-Wagner plots to calculate the average crystallite size. The XRD data analysis showed that average crystallite sizes of the as-synthesized metal oxide phases were between 4 nm and 76 nm and average diameters calculated from SEM image were between 15 nm and 83 nm. The XRD studies also disclosed that average crystallite size and lattice microstrain of the CuO phases remain almost same (43 nm–46 nm and 2.074×10−3 to 2.665×10−3) for pure CuO and mixed CuO–NiO; but in case of mixed CuO–NiO–ZnO it is found to decrease in size to 11 nm where lattice microstrain increases to 9.653×10−3. Line broadening of diffraction peaks from microstrain contribution was between 0.02 and 0.01. Degree of crystallinity (%) of CuO phases found to decrease from 81 to 71. Dislocation density of CuO phases found to increase from 6.63×10−4nm−2 to 12.68×10−3nm−2. X-ray density of CuO phases increased from 6.48 to 6.53 g/cm3. Where this calculated small dislocation density well agreed with the high crystallinity. Crystal structure and specific surface area were determined from lattice constants and X-ray density. These synthesized nanopowders showed the existence of monoclinic, cubic, and hexagonal phases. The obtained NPs of multi-metal oxide explained more than one phases with different size, shape, and morphology at nano scale.