Bimetallic Nanocatalysts Research Articles

Efficient sonocatalytic degradation of orange II dye and real textile wastewater using peroxymonosulfate activated with a novel heterogeneous TiO2–FeZn bimetallic nanocatalyst

TiO2–FeZn nanocatalyst combined with sonolysis were used to activate peroxymonosulfate (PMS) as a highly efficient advanced oxidation process (US/TiO2–FeZn/PMS) for the decoloration of orange II dye (OII) and real textile wastewater. The characterization of the as-synthesized NPs was performed by SEM, FTIR, EDX and XRD analyses. Optimal experimental conditions of operational parameters were obtained: pH = 3, 15 mg/L initial OII concentration, 0.2 g/L PMS, 0.7 g/L nanocatalyst dosing, and 300 W ultrasonic power. The decolorization was observed to increase with increasing the dose of nanocatalyst and the ultrasonic power, and with decreasing pH (under acidic conditions). Under optimal experimental conditions, decolorization and COD removal of textile wastewater were 99.9% and 74.6%, respectively, at 40 min. The TiO2–FeZn/PMS/US as a novel process exhibited a higher removal of OII (95%) than TiO2 NPs/PMS/US process (54%). The OII removal efficiency by the different processes decreased in the following order: TiO2–FeZn/US/PMS > TiO2–FeZn/PMS > TiO2–FeZn/US > TiO2 /US/PMS > US/PMS > TiO2–FeZn > PMS > US. The recyclability study revealed that the process could be reused up to three consecutive cycles. The current US/nanocatalyst/PMS system was concluded to be an efficient, reusable and stable nanocatalyst for the oxidation of textile dyes.

Preparation adjacent Ni-Co bimetallic nano catalyst for dry reforming of methane

Catalytic reforming for hydrogen production is a bridge to sustainable energy. Coking is a big challenge for the industrialization of DRM. The key is to maintain a balance between the formation rate of *C and that of *O. A novel preparation strategy of Ni-Co nano alloy catalysts was proposed with microemulsion coupling with antisolvent extraction strategy.The prepared nanoparticles were highly dispersed and Ni,Co were closely adjacent. Compared with the monometallic 10Ni0Co/SiO2 catalyst and 0Ni10Co/SiO2 catalyst, the as-prepared bimetallic 5Ni5Co/SiO2 nano alloy catalyst showed the best catalytic activity. On the monometallic 10Ni0Co/SiO2 catalyst, owing to the faster cracking of methane on Ni particles, the catalytic activity decreased 10% by coking during the 50 h test. However, 0Ni10Co/SiO2 catalyst was deactivated by the oxidation of Co. In the 100 h test of 5Ni5Co/SiO2 bimetallic catalyst, the catalytic activity remained stable. TPSR showed that the dissociation of methane and the generation of *C was slightly inhibited and the activation of CO2 was intensified. More activated *O enhanced the reaction of *C or *CHx and *O. The anti-coking performance was improved. The results provide implications for anti-coking catalysts for catalytic reforming.

Restructured zeolites anchoring singly dispersed bimetallic platinum and zinc catalysts for propane dehydrogenation

Restructuring of a heterogeneous catalyst under reaction conditions is a common phenomenon. Severe restructuring of a catalyst can result in deactivation in many catalytic systems—for example, the catalytic dehydrogenation of propane to propylene. Herein, we report the utilization of catalyst restructuring to improve activity and stability for the propane dehydrogenation reaction. A bimetallic platinum and zinc (Pt1Znm) catalyst protected by an in situ restructured silicalite-1 zeolite is prepared. The catalyst yields outstanding activity (initial conversion of ∼69.2%, initial selectivity of ∼91.1%) with high stability at 580°C, which is better than several commercial catalysts. Characterization shows the singly dispersed bimetallic sites of Pt1Znm serve as the catalytic sites during the reaction. Moreover, the less-stable silicalite-1 zeolite undergoes restructuring during the dehydrogenation reaction, forming a crucial protective layer on the Pt1Znm bimetallic nanocatalysts.

Regulating Hollow Carbon Cage Supported NiCo Alloy Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution Reaction.

The NiCo alloy is one of the most promising alternatives to the noble-metal electrocatalysts for the hydrogen evolution reaction (HER); however, its performance is largely restricted by insufficient active sites and low surface area. Here, we fabricated a hierarchical hollow carbon cage supported NiCo alloy (denoted as HC NiCo/C) and a bulk NiCo alloy (denoted as NiCo) by reduction of a partially ZIF-67 etched ZIF-67@NiCo-LDH (LDH = layered double hydroxide) precursor and a fully ZIF-67 etched NiCo-LDH precursor, respectively. The as-prepared HC NiCo/C, in which the Ni29Co71 alloy nanocrystals with an average 6 nm size were encapsulated in graphitic carbon layers, provided a vastly increased electrochemically active surface area (ca. 13 times than the NiCo) and abundant catalytic active sites, which resulted in a higher HER performance with an overpotential of 99 mV than the 198 mV for NiCo at 10 mA cm-2. Detailed experimental results suggested that only the HC NiCo/C possessed the active alloy surface composed of unsaturated Ni0 and Co0 atoms, and both the metal-support interaction and alloying effect influenced the electronic structure of Co and Ni in HC NiCo/C, whereas the NiCo exhibited pure Ni surface. Theoretical calculations further revealed the Ni29Co71 alloy surface in HC NiCo/C possessed the appropriate adsorption energy of the intermediate state (adsorbed H*). This work provided new insight into the construction of the stable small-sized bimetallic alloy nanocatalysts by regulating the reduction precursors.

Mechanistic Studies into the Selective Production of 2,5-furandicarboxylic Acid from 2,5-bis(hydroxymethyl)furan Using Au-Pd Bimetallic Catalyst Supported on Nitrated Carbon Material

Aerobic oxidation of bio-sourced 2,5-bis(hydroxymethyl)furan (BHMF) to 2, 5-furandicarboxylic acid (FDCA), a renewable and green alternative to petroleum-derived terephthalic acid (TPA), is of great significance in green chemicals production. Herein, hierarchical porous bowl-like nitrogen-rich (nitrated) carbon-supported bimetallic Au-Pd nanocatalysts (AumPdn/ N-BNxC) with different nitrogen content and bimetal nanoparticle sizes were developed and employed for the highly efficient aerobic oxidation of BHMF to FDCA in sodium carbonate aqueous solution. The reaction pathway for catalytic oxidation of BHMF went through the steps of BHMF→HMF→HMFCA→FFCA→FDCA. Kinetics studies showed that the activation energies of BHMF, HMF, HMFCA, and FFCA were 58.1 kJ·moL−1, 39.1 kJ·moL−1, 129.2 kJ·moL−1, and 56.3 kJ·moL−1, respectively, indicating that the oxidation of intermediate HMFCA to FFCA was the rate-determining step. ESR tests proved that the active species was a superoxide radical. Owing to the synergy between the nitrogen-rich carbon support and bimetallic Au-Pd nanoparticles, the Au1Pd1/N-BN2C nanocatalysts exhibited BHMF conversion of 100% and FDCA yield of 95.8% under optimal reaction conditions. Furthermore, the nanocatalysts showed good stability and reusability. This work provides a versatile strategy for the design of heterogeneous catalysts for the highly efficient production of FDCA from BHMF.

Conjugated dual size effect of core-shell particles synergizes bimetallic catalysis

Core-shell bimetallic nanocatalysts have attracted long-standing attention in heterogeneous catalysis. Tailoring both the core size and shell thickness to the dedicated geometrical and electronic properties for high catalytic reactivity is important but challenging. Here, taking Au@Pd core-shell catalysts as an example, we disclose by theory that a large size of Au core with a two monolayer of Pd shell is vital to eliminate undesired lattice contractions and ligand destabilizations for optimum benzyl alcohol adsorption. A set of Au@Pd/SiO2 catalysts with various core sizes and shell thicknesses are precisely fabricated. In the benzyl alcohol oxidation reaction, we find that the activity increases monotonically with the core size but varies nonmontonically with the shell thickness, where a record-high activity is achieved on a Au@Pd catalyst with a large core size of 6.8 nm and a shell thickness of ~2–3 monolayers. These findings highlight the conjugated dual particle size effect in bimetallic catalysis.

Palladium based bimetallic nanocatalysts: Synthesis, characterization and hydrogen fuel production

In this study, Palladium dopped Copper oxide nanoparticles (CuO@Pd NPs) were synthesized by an environmentally friendly green synthesis method for hydrogen production experiments. Characterizations of synthesized nanoparticles; UV–vis Spectroscopy to characterize the optical properties, Scanning Electron Microscopy (SEM) to determine the morphology and particle size of the particles, Fourier Transform Infrared Spectroscopy (FTIR) for the analysis of organic groups, and X-ray Diffraction Spectroscopy (XRD) for the crystal lattice type analysis were used. As a result of the UV–vis Spectroscopy characterization of the synthesized nanoparticles, an absorption peak compatible with metals visible at 422 nm was observed. According to the XRD analysis results, the crystal size observed in the cubic phase was calculated as approximately 4.426 nm. According to the results of the SEM analysis the average particle size of the cubic nanoparticles was seen as 26.2 nm. The catalytic properties of CuO@Pd NPs were determined by the sodium borohydride hydrolysis reaction. As a result of catalyst, substrate, temperature, and reusability experiments, some activation parameters required for a catalytic reaction of nanoparticles were calculated. The activation energy of CuO@Pd NPs was calculated as 37.39 kJ/mol, enthalpy change as 34.84 kJ/mol, and entropy change as −189.8 J/mol.K. TOF, which is an indicator of hydrogen efficiency, was calculated as 1513.4 h−1. Reusability experiments were carried out in 4 cycles and the catalytic activity of CuO@Pd NPs was measured as 70 %. In light of these results, it was seen that nanoparticles provide optimal conditions for a catalytic reaction.

A bimetallic nanocatalyst from carbonaceous waste for crystal violet degradation

The contamination of wastewater by cationic dyes has caused considerable environmental problems, such as an imbalance in the aquatic ecosystem and a decrease in photosynthetic activity. In this context, this study aims to synthesize and characterize a bimetallic nanocatalyst (MMT@TiO2-NPs/ZnO-NPs), as well as to evaluate its photocatalytic activity in crystal violet (CV) dye degradation. The samples were characterized by X-ray diffraction (XRD), Field Emission Gun – Scanning Electron Microscope (FEG-SEM), N2 physisorption (BET/BJH methods), UV–Vis Diffuse Reflectance Spectroscopy (DRS), zeta potential (ZP), and zero charge point (pHZCP). Central composite rotational design (CCRD 2³) was used for the experimental design to obtain the ideal condition. The diffractograms showed characteristic peaks of MMT (analcime and neighborite), ZnO-NPs (zincite) and TiO2-NPs (anatase) with an average crystallite size determined in the range of 10–50 nm. The MMT@TiO2-NPs/ZnO-NPs showed a high surface area (98.8 ± 0.6 m2 g−1) with IV-type isotherm characteristic of porous materials. Moreover, a heterogeneous morphology with an average particle size of around 16 nm. ZP showed a negative charge (−3.84 ± 0.07 mV) and pHZCP ≈ 5.80, favoring interactions with the CV dye. Ideal condition was [CV] = 32.5 g L−1, [MMT@TiO2-NPs/ZnO-NPs] = 1.75 g L−1 and pH = 12, with a CV removal of 99.97% (k = 0.0789 min−1) under visible radiation. Regarding reuse, MMT@TiO2-NPs/ZnO-NPs showed great photocatalytic stability after six cycles with 90.62% for the CV degradation. Therefore, MMT@TiO2-NPs/ZnO-NPs showed great potential for use in the treatment of industrial textile effluents, helping in the waste management strategy from mid-to long-term perspectives.

Achieving Tunable Selectivity and Activity of CO2 Electroreduction to CO via Bimetallic Silver-Copper Electronic Engineering.

Limited comprehension of the reaction mechanism has hindered the development of catalysts for CO2 reduction reactions (CO2 RR). Here, the bimetallic AgCu nanocatalyst platform is employed to understand the effect of the electronic structure of catalysts on the selectivity and activity for CO2 electroreduction to CO. The atomic arrangement and electronic state structure vary with the atomic ratio of Ag and Cu, enabling tunable d-band centers to optimize the binding strength of key intermediates. Density functional theory calculations confirm that the variation of Cu content greatly affects the free energy of *COOH, *CO (intermediate of CO), and *H (intermediates of H2 ), which leads to the change of the rate-determining step. Specifically, Ag96 Cu4 reduces the free energy of the formation of *COOH while maintaining a relatively high theoretical overpotential for hydrogen evolution reaction(HER), thus achieving the best CO selectivity. While Ag70 Cu30 shows relatively low formation energy of both *COOH and *H, the compromised thermodynamic barrier and product selectivity allows Ag70 Cu30 the best CO partial current density. This study realizes the regulation of the selectivity and activity of electrocatalytic CO2 to CO, which provides a promising way to improve the intrinsic performance of CO2 RR on bimetallic AgCu.

Conversion of Biomass‐derived Aldehydes using Environmentally Benign CuNi nanocatalyst

AbstractIn the present work, bimetallic CuNi‐12 (1 : 2 molar ratio of Cu : Ni) was synthesized via a liquid‐phase reduction method and utilized for the efficient and selective hydrogenation of biomass‐derived aldehydes and ketones with 2‐propanol as hydrogen source and KOH as base. The synergistic effect between copper and nickel metal enhanced the catalytic activity and selectivity. Bimetallic CuNi‐12 nanocatalyst is highly efficient and sustainable for converting various aldehyde and ketones with 100 % conversion and selectivity. Biomass derived alcohol i. e. furfural, cinnamaldehyde, 5‐hydroxy methyl furfural were utilized as substrate and converted into alcohol with 100 % conversion and selectivity. Bimetallic nanocatalyst CuNi‐12 having high surface area and it is reusable, magnetically separable and recyclable up to seven cycles.

Recent advances in synthesis and characterization of iron-nickel bimetallic nanoparticles and their applications as photo-catalyst and fuel additive.

Iron-nickel bimetallic nanoparticles (Fe-Ni BMNPs) are prepared by combining two different metals by using the bottom-up approach. The resulting material has entirely different properties as compared to both the metals. The product is examined by using different analytical instruments such as.; scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), MDIJADE, ORIGIN pro to characterize their morphology, crystallinity and elemental composition and the final data has been statistically analyzed. SEM findings show that most nanoparticles are irregular in form and range in size from 10 nm to 100 nm. The findings of the TEM verified that the particles between 10 nm and 50 nm are irregular in size shape. The products acquired utilized as a fuel additive to monitor oil effectiveness by studying various parameters. The degradation of methylene blue dye depends directly on the concentration of the nanocatalyst. Different parameters also use the freshly prepared bimetallic nanocatalyst to investigate the efficacy of the kerosene fuel. By adding a tiny quantity of the nanocatalyst, the value of the flash point and fire point is significantly reduced. The nanocatalyst does not affect the cloud point and pour point to a large extent. The bimetallic nanocatalyst therefore has very excellent catalytic characteristics.

In situ SERS reveals the route regulation mechanism mediated by bimetallic alloy nanocatalysts for the catalytic hydrogenation reaction.

Synthesizing arylamines with high selectivity via hydrogenation of nitroaromatics is a long-standing challenge because of the complex reaction pathways. Revealing the route regulation mechanism is the key to obtain high selectivity of arylamines. However, the underlying reaction mechanism of route regulation is uncertain owing to a lack of direct in situ spectral evidence of the dynamic transformation of intermediate species during the reaction process. In this work, by using in situ surface-enhanced Raman spectroscopy (SERS), we have employed 13 nm Au100-x Cu x nanoparticles (NPs) deposited on a SERS-active 120 nm Au core to detect and track the dynamic transformation of intermediate species of hydrogenation of para-nitrothiophenol (p-NTP) into para-aminthiophenol (p-ATP). Direct spectroscopic evidence demonstrates that Au100 NPs exhibited a coupling route with the in situ detection of the Raman signal assigned to coupling product p,p'-dimercaptoazobenzene (p,p'-DMAB). However, Au67Cu33 NPs displayed a direct route without the detection of p,p'-DMAB. The combination of X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations reveals that Cu doping can favor the formation of active Cu-H species owing to the electron transfer from Au to Cu, which can promote the formation of phenylhydroxylamine (PhNHOH*) and favor the occurrence of the direct route on Au67Cu33 NPs. Our study provides direct spectral evidence demonstrating the critical role of Cu in route regulation for the nitroaromatic hydrogenation reaction at a molecular level and clarifies the route regulation mechanism. The results have significant implications for revealing multimetallic alloy nanocatalyst mediated reaction mechanisms and help to guide the rational design of multimetallic alloy catalysts for catalytic hydrogenation reactions.

Doped metal clusters as bimetallic AuCo nanocatalysts: insights into structural dynamics and correlation with catalytic activity by in situ spectroscopy.

Co-doped Au25 nanoclusters with different numbers of doping atoms were synthesized and supported on CeO2. The catalytic properties were studied in the CO oxidation reaction. In all cases, an enhancement in catalytic activity was observed compared to the pure Au25 nanocluster catalyst. Interestingly, a different catalytic performance was obtained depending on the number of Co atoms within the cluster. This was related to the mobility of atoms within the cluster's structure under pretreatment and reaction conditions, resulting in active CoAu nanoalloy sites. The evolution of the doped Au clusters into nanoalloys with well-distributed Co atoms within the Au cluster structure was revealed by combined XAFS, DRIFTS, and XPS studies. Overall, these studies contribute to a better understanding of the dynamics of doped nanoclusters on supports upon pretreatment and reaction, which is key information for the future development and application of bimetallic nanocluster (nanoalloy) catalysts.

Green Synthesis of Bimetallic ZnO-CuO Nanocatalyst for the Hydro-dechlorination of 1,2-Dichlorobenzene and 3-Chlorophenol

Bimetallic nanoparticles exhibit advantageous catalytic, optical and electrical properties and among the various methods of synthesis of nanoparticles, green synthesis gained great attention due to its simplicity, cost effective, ecofriendly and versatility. In view of this, the present work intended to synthesize the ZnO-CuO bimetallic nanoparticles using aqueous root extract of Suaeda maritima (L.) Dumort. The bimetallic nanoparticles synthesized were observed to be spherical in shape with particle size in the range of 20-45 nm and the particles were distributed with less aggregation. The synthesized nanoparticles have 41% of zinc element and 33% copper with hexagonal phase crystalline structure of zinc oxide and monoclinic copper oxide phase. The synthesized ZnO-CuO bimetallic nanoparticles were used for the hydro-dechlorination of 1,2-dichlorobenzene and 3-chlorophenol. The results indicated that rapid dechlorination was observed during the initial time of study. The percentage dechlorination of 19.37 ± 0.243 and 15.52 ± 0.193% was observed within 5 min of the study for 1,2-dichlorobenzene and 3-chlorophenol, respectively. The high % dechlorination was achieved within 25 min wherein the % dechlorination was observed to be 93.35 ± 0.103 and 89.75 ± 0.091 for 1,2-dichlorobenzene and 3- chlorophenol, respectively. This study reports the cost-effective and eco-friendly method for synthesizing ZnO-CuO bimetallic nanoparticles that can utilize for the dechlorination of various polychlorinated aromatic compounds in natural samples.

Research on Pd-Ni/AC Bimetallic Nano-catalyst for Catalytic Hydrodechlorination of Bleached Shellac

Research on Pd-Ni/AC Bimetallic Nano-catalyst for Catalytic Hydrodechlorination of Bleached Shellac

Recyclable Cu–Ag bimetallic nanocatalyst for radical scavenging, dyes removal and antimicrobial applications

An ecofriendly and cost effective green method has been used for the synthesis of recyclable, high functional nanoparticles. Bimetallic nanoparticles (BmNPs), Cu–Ag, have been synthesized using beetroot extract as reducing and capping agent. Formation of BmNPs was initially confirmed by UV–visible analysis, having distinct peaks of Ag at 429 nm and Cu at 628 nm. FTIR analysis also confirmed the association of bioactive phytochemicals with Cu–Ag nanoparticles. Crystallinity and morphology of BmNPs was determined through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS) and energy dispersion X-ray spectroscopy (EDAX). The size of spherical shape Cu–Ag BmNPs was found to be 75.58 nm and EDAX studies confirmed the percent elemental composition of Cu and Ag in synthesized nanocatalyst. Results of different analysis provided supported evidences regarding the formation of BmNPs. Catalytic potential of BmNPs was tested for the degradation of rhodamine B (Rh–B), methylene blue (MB) and methyl orange (MO) dyes. Cu–Ag BmNPs exhibited outstanding catalytic activity for the degradation of selected organic dyes and percent degradation was recorded more than 90% for each dye. In addition, antiradical property of BmNPs was tested employing DPPH● and ABTS●+ assays and it was found to be promising. Synthesized BmNPs also exhibited strong antimicrobial activity against Salmonella typhimurium and Bacillus subtilis. Recyclability of nanoparticles was also evaluated and recovery from dye degradation reaction mixture was successfully achieved. The recovered nanoparticles exhibited same catalytic potential for the degradation of Rh–B. The objective of the current study was to synthesize BmNPs Cu–Ag employing a cost effective green method having promising catalytic, antiradical and antimicrobial potential. Further, BmNPs were reused after recovery from catalytic reactions, proving that BmNPs can be recycled having the same efficiency as that of a freshly prepared Cu–Ag BmNPs.

Green and facile synthesis of heterojunction nanocatalyst: Insights and mechanism of antibiotics removal

Detecting of antibiotics in the aquatic environment is a serious health concern due to the development of antibiotic-resistant genes in humans and marine life. The current investigation aims to synthesize highly efficient heterojunction bimetallic nanocatalyst (Cu0 + Ag0)@Bentonite in a facile and ‘greener’ route. In situ, the phytochemicals of P. guajava leaves synthesize the Cu0 and Ag0 nanoparticles onto the bentonite support media. The advanced analytical methods characterize the nanomaterials extensively. The potential antibiotics (amoxicillin and sulfamethazine) are treated in photo-Fenton-like processes utilizing the UV-A and LED (Visible) light sources. The bimetallic (Cu0 + Ag0)@Bentonite exhibited a synergized in the photo-induced degradation of amoxicillin and sulfamethazine. The effect of pH, initial pollutant concentrations, and the presence of interfering ions optimize the removal efficiency and demonstrate insights into the reaction mechanism. The photo-Fenton-like degradation of AMX and SMZ was found to be 84 % and 74 %, respectively, under the UV-A illumination employing (Cu0 + Ag0)@Bentonite nanocatalyst. Similarly, the process mineralizes a significant amount of these pollutants, i.e., 66 % and 62 % of SMX and SMZ, respectively, using UV-A irradiation., enhancing the applicability of the catalyst. The nanocatalyst showed greater stability in the reactor operations, and Cu(II) leaches very minimally extent in the reaction pathways. The real water implications inferred the potential of novel nanocatalysts in scaling up the process for the decontamination of water contaminated with amoxicillin and sulfamethazine.

Pd-Doped Perovskite Oxides with Phase Transition and Bimetallic Nanocatalyst Exsolution to Achieve Highly Active Bifunctional Fuel Electrodes for Reversible Solid Oxide Electrochemical Cells

The reducibility of B-site elements in perovskite (ABO3) structures is one of the important factors that accelerate the in-situ exsolution of metallic nanocatalysts. Herein, a highly catalytically active and durable Pd-doped perovskite-based anode material (La0.6Sr0.4Co0.15Fe0.8-xPdxO3-\U0001d6ff (LSCFP)) was developed for reversible SOCs. Under fuel electrode conditions, the LSCFP material is fully transformed into a stable Ruddlesden-Popper phase decorated with bimetallic Co-Fe nanocatalysts. Highly reducible Pd doping in the perovskite lattice effectively reduces the energy barrier for exsolution and formation of bimetallic catalysts on the electrode surface and promote phase transformation into the stable Ruddlesden-Popper-phase in the reducing atmosphere. The SOC with LSCFP fuel electrode yielded outstanding performances in both fuel cell and electrolysis cell modes at 850 °C, with remarkable reversible-cyclic stability. These results indicate that the novel LSCFP, which can simultaneously perform phase transition and bimetal exsolution under reducing conditions, is a very promising candidate as a bifunctional fuel electrode for reversible SOCs.

Defect‐Decorated NiFe Bimetallic Nanocatalysts for the Enhanced Hydrodeoxygenation of Guaiacol

AbstractSeries of Ni‐based nanocatalysts were fabricated for the HDO of lignin‐derived guaiacol to cyclohexane via a single‐source Ni−Fe−Al layered double hydroxide precursor route and characterized by XRD, BET, TEM, XAS, XPS, H2‐TPR, H2‐TPD, NH3‐TPD, and pyridine absorbed in situ FT‐IR. As‐fabricated bimetallic NiFe nanocatalyst bearing a Fe/Ni molar ratio of 0.5 : 3 attained a higher cyclohexane yield of 70.5 % under mild reaction conditions (i. e., 230 °C and 1.0 MPa of initial hydrogen pressure), compared to monometallic Ni and other NiFe bimetallic nanocatalysts, as well as monometallic Ni and bimetallic NiFe catalysts prepared by the impregnation method. Combination of experimental results and density functional theory calculations manifested that interfacial FeOx species profoundly facilitated the demethoxylation processes of guaiacol and 2‐methoxycyclohexanol intermediate, while both bimetallic NiFe sites and interfacial FeOx species greatly promoted the dehydroxylation of cyclohexanol intermediate.

Green synthesis of bimetallic nanocomposite: Efficient use of nanocomposite in the removal of phenol and n-(n-Propyl) thiourea by photo-Fenton-like process

The contamination of water bodies with emerging and persistent water contaminants, viz., phenol and n-(n-propyl) thiourea (NNPT) is a severe environmental and health concern. This study aims to obtain the novel bimetallic heterogeneous nanocatalyst supported with natural bentonite using a facile greener route. The in situ nanoparticles, i.e., Fe0 and Ag0, were obtained utilizing natural phytochemicals from leaf extracts of P. guajava. The XPS and XRD analyses inferred the presence of Ag0(NPs) and Fe0(NPs) in the composite material. Moreover, the bandgap energy of nanocomposite material (Ben@(Fe0+Ag0)) was 2.25 eV compared to the pristine bentonite of 3.25 eV. Further, the nanocatalyst was efficiently employed in the photo-Fenton-like process to eliminate of phenol and NNPT in an aqueous medium. The degradation efficiency of the catalyst for targeted pollutants was found to be 73% (for phenol) and 95% (for NNPT) in the photo-Fenton-like process for 2 h of UV-A illumination. Similarly, a significant efficiency (Ca. 60% for phenol and Ca. 90% for NNPT) was achieved utilizing the LED (Visible) light illumination in a similar photo-Fenton-like process. The degradation of these two pollutants has predominantly proceeded through the •OH radicals. The photo-Fenton-like process mineralized these two pollutants significantly. Several parameters optimized the Fenton-like process, including pH, catalyst dose, and H2O2 concentration. The repeated photo-Fenton-like processes for 4 consecutive cycles showed an insignificant decrease in the efficiency of nanocatalyst, at least in the elimination of these two contaminants. The process was further employed to eliminate phenol and NNPT in the natural water samples spiked with known concentrations of these pollutants. The promising approach is excellent for the removal of recalcitrant environmental pollutants.