Oxide Nanocatalyst Research Articles

Sustainable production of biodiesel from waste cooking oil using magnesium oxide nano catalyst: An optimization study

Biodiesel is rapidly becoming an efficient substitute for fuel and a potentially significant future renewable energy source. In recent years, used cooking oil has been used as a feedstock for biofuel to reduce production costs. Due to its high catalytic activity, low cost, and eco-friendliness, Nano magnesium oxide (MgO) has attracted attention as a catalyst for biodiesel production. Our work presents the preparation of nanomagnesium oxide (MgO) by the sol–gel method, and its characterization. Optimum conditions and the productive combination of waste cooking oil, methanol, and the synthesized nanocatalyst were predicted using response surface methodology. The optimum conditions were methanol to oil ratio of 7:1, temperature of 50 °C and time of 60 min. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. The predicted model's F-value was 9.09 indicating that the model is significant. The model's pure error had a poor correlation, as the "Lack of Fit F-values” 4.16. The quadratic model fits the data well because the R-squared value for the model equation 92%. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. Biodiesel was characterized using gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy.

Exploration of cobalt-based spinel oxide nanocatalysts MCo2O4 (M = Mn, Fe, Co, Ni, Cu, Zn) for glucose electrochemical sensing: NiCo2O4 exhibits largest Faradaic current

In traditional glucose sensing, glucose undergoes an enzyme-catalyzed oxidation reaction (GOR) on the electrode, causing electron transfer and generating a Faradaic current, which allows for quantitative glucose concentration analysis by measuring the current. Replacing enzymes with transition metal-based catalysts for glucose electrochemical sensing is a promising approach. As an extension of the study of spinel oxide Co3O4 for glucose electrochemical sensing, a series of cobalt-based spinel oxide nanocatalysts, MCo2O4 (M = Mn, Fe, Co, Ni, Cu, Zn), were prepared and studied. Their electrocatalytic oxidation activities for 3 mM glucose in 0.1 M KOH electrolyte solution (pH = 13) at potentials of 0.5 ∼ 0.6 V (vs Hg/HgO) are in the order: NiCo2O4 > CuCo2O4 > MnCo2O4 > Co3O4 > FeCo2O4 > ZnCo2O4, the Faradic current by NiCo2O4 is more than three times that of Co3O4. When NiCo2O4 is loaded onto a carbon cloth electrode for glucose electrochemical sensing, it exhibits high linear sensitivity and stability. Furthermore, theoretical calculations revealed that the high electrocatalytic oxidation activity of NiCo2O4 for glucose is due to its effective reduction of the Gibbs free energy barrier for the desorption of intermediates to form glucose oxidation product. Finally, it is proposed that the electrocatalytic oxidation activities of MCo2O4 (M = Mn, Fe, Co, Ni, Cu, and Zn) towards glucose exhibit a “volcano plot” relationship with their d-band centers. This offers valuable guidance into using the d-band center as a descriptor to screen effective glucose electrocatalysts for glucose sensing and potentially other applications.

Synthesis of omega-3 mediated copper (ω-3-Cu) and copper oxide (ω-3-CuO) nanocatalyst dual application of dye decolourization and aerobic oxidation of eco-friendly sustainable approach.

In this study, ω-3-Cu and ω-3-CuO nanocatalysts were investigated for industrial environmental issues. Nowadays, green methodology is very important for addressing industrial environmental issues. In this regard, the current study focuses on ω-3-Cu and ω-3-CuO used for aerobic oxidation and dye decolourization via an eco-friendly approach. The synthesised ω-3-Cu and ω-3-CuO nanocatalysts were characterised using FT-IR, UV, XRD, TEM, GC-MS, 1H and 13C NMR. The results showed that the prepared ω-3-Cu catalyst was almost spherical with forms and sizes typically less than 20nm and the ω-3-CuO nanocatalyst 10nm. The ω-3 Cu and ω-3-CuO nanocatalysts were investigated for the conversion of pentan-2-ol into pentan-2-one, which was observed by GC-MS analysis. The ω-3-CuO nanocatalyst decolourised the Brilliant Blue dye more quickly (100% in 30min) than ω-3-Cu (85% in 60min) and ω-3 (no colour in 60min), and Rhodamine B was not decolourised because our ω-3-Cu and ω-3-CuO nanocatalysts inactivated the rhodamine B dye. The aerobic oxidation process using the ω-3-CuO nanocatalyst as the end product of pentan-2-one resulted in a retention time of 30.33. To the best of our knowledge, ω-3-Cu and ω-3-CuO nanocatalysts have not been documented for their application in decolourisation and aerobic oxidation. By highlighting the potential use for the continued advancement and innovation of ω-3-CuO nanocatalysts in the long-term future, cost-effective and eco-friendly methods for producing reusable ω-3-CuO nanocatalysts have the potential to be applied in advanced technical fields, particularly in the areas of dye decolourisation and aerobic oxidation. Finally, we successfully accomplished these processes using the ω-3-CuO nanocatalyst. The ω-3-CuO nanocatalyst evaporated more quickly than the ω-3-Cu and ω-3-CuO nanocatalyst, without any additional energy. ω-3-CuO is the most effective nanocatalyst for dye decolourization and aerobic oxidation (Dual application). ω-3-CuO is used in textile and pharmaceutical industries.

Ferric oxide/ammonium nitrate nanocomposite: novel catalyzed eco-friendly oxidizer with advanced decomposition kinetics

ABSTRACT Ammonium nitrate (AN) could serve as a green substitute for ammonium perchlorate (AP) in halogen-free oxidizers. However, AN faces issues with endothermic phase transitions, melting, and sublimation. Ferric oxide, a common catalyst for solid propellants, was used to catalyze AN. This study reports the synthesis of 5 nm colloidal ferric oxide particles, integrated into the AN matrix through co-precipitation. Energy dispersive analysis by X-rays (EDAX) confirmed the proper dispersion of the ferric oxide catalyst. The impact of ferric oxide on AN decomposition enthalpy was assessed using differential scanning calorimetry DSC. Virgin AN showed an endothermic decomposition enthalpy of +1708 J/g, while catalyzed AN showed exothermic decomposition of −732 J/g. Ferric oxide nanocatalyst offered a decrease in AN main decomposition temperature by 83°C using thermogravimetric analysis (TGA). Activation energy dropped significantly, from 87.3 to 16.8 KJ/mol (Kissinger model), due to ferric oxide’s catalytic effect involving ferric and ferrous ion reactions.

Selective Synthesis of Renewable Diesel Fuel Precursors via C–C Condensation of Biomass-Derived Furans Using a Niobium Oxide Nanocatalyst

Selective Synthesis of Renewable Diesel Fuel Precursors via C–C Condensation of Biomass-Derived Furans Using a Niobium Oxide Nanocatalyst

MOF‐Derived FeCoO/N‐Doped C Bifunctional Electrode for H2 Production Through Water and Glucose Electrolysis

AbstractThe glucose oxidation reaction (GOR) is a potential alternative to water oxidation because of its relatively low thermodynamic potential and the high availability of glucose. Herein, a FeCoO/N‐doped C electrode derived from metal–organic framework (MOF) materials is applied, which is synthesized in several steps through the controlled deposition of Fe–Co oxide nanocatalysts onto Co –N‐doped C nanofibers on a Ni foam substrate and demonstrate exceptional electrocatalytic activity for both the GOR and overall water splitting. Here, a bifunctional electrocatalyst derived from MOF, FeCoO/N‐doped C is reported, for glucose oxidation reaction (GOR) and hydrogen evolution reaction (HER). The MOF‐derived FeCoO/N‐doped C (+/‐) as a bifunctional electrocatalyst exhibits a cell voltage of 1.4 V for the GOR&HER, to reach a current density of 10 mA cm−2, which is 280 mV lower than that for the oxygen evolution reaction (OER)&HER (1.68 V). This study reveals that GOR is an energy‐efficient and affordable source of H2 and value‐added chemicals.

Eco-friendly production of biodiesel from Carthamus tinctorius L. seeds using bismuth oxide nanocatalysts derived from Cannabis sativa L. Leaf extract

Global challenges in environmental protection, social welfare, and economic growth necessitate increased energy production and related services. Biofuel production from waste biomass presents a promising solution, given its widespread availability. This study focuses on converting highly potent Carthamus tinctorius L. seed oil (51 % w/w) into sustainable biofuel using a novel, highly reactive, recyclable, and eco-friendly bismuth oxide (Bi2O3) nano-catalyst derived from Cannabis sativa L. leaf extract. The physio-chemical properties of the synthesized biodiesel were analyzed using Gas Chromatography/Mass Spectroscopy (GC-MS), Nuclear Magnetic Resonance (NMR), and Fourier-Transform Infrared Spectroscopy (FTIR). Additionally, the green Bi2O3 nanoparticles were characterized through Scanning Electron Microscopy (SEM), Energy Diffraction X-Ray (EDX), and X-Ray Diffraction (XRD). Optimal conditions for biodiesel production were determined using Response Surface Methodology (RSM) in combination with Central Composite Design (CCD), focusing on molar ratio, catalyst loading, and reaction duration. The highest output (94 %) of C. tinctorius-derived biodiesel (CTBD) was achieved under the following conditions: a temperature (75 °C) for time duration (100 min), a methanol to oil ratio (6:1), and a catalyst loading (0.69 wt%). The resulting biodiesel met international standards, with a sulphur content of 0.00097 wt%, and an acid value of (0.34 mg KOH/g). This study demonstrates that converting C. tinctorius waste seed oil into clean bioenergy is an effective waste management strategy that minimizes environmental impact.

Ruthenium(III) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles: A new heterogeneous nanocatalyst for efficient oxidation of hydrocarbons with tert-butyl hydroperoxide

In the present work, an unsymmetrical salen-type ruthenium(III) complex, Ru(salenac)Cl, where the unsymmetrical tetradentate Schiff base H2salenac = salicylideneiminoethyliminopentane-2-one, was synthesized and anchored on the surface of aminopropyl-functionalized silica-coated γ-Fe2O3 magnetic nanoparticles. The characterization of the resulting γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanoparticles was performed using XRD, FT-IR, VSM, TGA, ICP, TEM, BET, SEM and EDX methods. The prepared γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl magnetic nanoparticle was successfully employed as an efficient heterogeneous nanocatalyst for alkenes epoxidation and alkanes oxidation with tert-butyl hydroperoxide (tert-BuOOH, 70 % aqueous solution) as oxidant in acetonitrile at ambient temperature. In the mentioned catalytic system, the intended products were obtained with good to excellent yields along with high selectivity. The heterogeneous γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanocatalyst can be recovered easily using an external magnet and recycled six times with no notable decrease in catalytic activity. Moreover, FT-IR, XRD, SEM and EDX techniques were used to characterize the recovered γ-Fe2O3@SiO2@APTES@Ru(salenac)Cl nanocatalyst and it was demonstrated that the catalyst maintained its structure intact following the recovery process.

A novel Ni-complex nanocatalyst for efficient electrochemical oxidation of alcohol in alkaline medium: Mechanism and DFT study

A novel catalyst based on nanoparticles of Ni(II) complex was developed to enhance the activity toward alcohol oxidation and hence its possible application in direct alcohol fuel cells (DAFCs). The [NiII(ABP)2] complex was formed in a molar ratio 1(Ni):2(ABP), where (ABP) was synthesized based on 4-(Dimethylamino)benzaldehyde (DMBA), 4-Aminoantipyrine (AAP) and 2-aminophenol (AP) through two condensation steps. Several characterization techniques were used to evaluate the structure of the synthesized compounds, such as elemental analysis, mass, FTIR, UV–Vis, 1HNMR , magnetic, molar conductance and XRD. Transmission and scanning electron microscope (TEM and SEM) images of separated [NiII(ABP)2] complex revealed particles with a size lower than 26 nm. SEM for [NiII(ABP)2]/GCE before and after ethanol oxidation was performed along with EDX and mapping techniques. The computational DFT (density functional theory) calculations supported the octahedral geometry shape of the prepared [NiII(ABP)2] chelate. Several octahedral structures involved in a purposed mechanism were studied using DFT to show the expected optimized shapes formed during ethanol oxidation. Also, the alcohol adsorption simulation was performed using Dmol3 numerical DFT modules to calculate the adsorption energy of alcohols on nickel complex surface. Additionally, the activity toward oxidation of alcohols with different sizes and stereochemistry (methanol, ethanol, propanol, and isopropanol) was investigated in an alkaline medium. The electrode activity was represented for each alcohol as a function of anodic oxidation current. Whereas the electrode achieved 14, 26, 6, and 4 mA cm−2 for methanol, ethanol, propanol, and isopropanol, respectively. Moreover, several parameters were calculated to judge the electrode performance, like diffusion coefficient, catalytic rate constant, stability, Tafel slope, and charge transfer resistance. The theoretical calculations and the experimental findings strongly correlate with each other, where Ni-complex showed the greatest catalytic activity toward ethanol oxidation.

Eco-friendly synthesis of indole-4-hydroxy-chromen-2-ones using green zinc oxide nanocatalyst and its assessment of anti-cancer studies against A549 cells

Zinc oxide (ZnO) nanoparticles have significant attention in the field of photocatalyst, super capacitor, battery and biomedicine due to their versatile potential and diverse applications. In the present study, ZnO was synthesized using Celastruspaniulatus leaf extract as a green fuel through combustion method. The morphological and structural studies of ZnO were characterized using XRD, FTIR, UV–Vis, SEM and TEM analysis. The PXRD pattern of ZnO as shown diffraction peaks of ZnO planes (100), (002), (102), (110), (103) and (112) are hexagonal Wurtzite ZnO structure. ZnO is formed in a discrete irregular hexagonal shape was confirmed by SEM analysis. The application of ZnO is achieved for the synthesis of (4-hydroxy3-(1H-indol-3-yl)-phenyl-methyl-chromen-2-one) and its derivatives via Knoevenagel/Michael addition reaction. All synthesized compounds showed good yield and are characterized using 1H NMR, 13C NMR and ESI-MS spectral studies. The reusability of the ZnO catalyst is tested and documented. Some of the synthesized chromenone compounds show promising anticancer activity against A549 cells with less concentration.

Novel Nanocatalysts for Simultaneous Ammonia Oxidation and Nitrate Reduction

Throughout recent years, nitrate reduction to ammonia has gained popularity in the scientific world to produce a carbon-free fuel [1]. However, research has primarily focused on low-concentration nitrate reduction, specifically for wastewater remediation. High-concentration effluents, such as ANSOL (Ammonium Nitrate), have emerged as a significant waste byproduct and a threat [2], with explosive characteristics and increasing production rates over the years [3]. This research seeks solutions to incorporate onsite waste treatment for generating electrical power, emphasizing the integration of waste streams as a distinctive opportunity. The integration aims to facilitate both power generation and the provision of clean water, with a focus on developing prototype systems designed to convert challenging Department of Defense (DoD) waste streams containing ANSOL into usable fuels for onsite energy generation.In this presentation, results from two distinct systems employing nanoparticle catalysts for the reduction of nitrates to ammonia, while simultaneously oxidizing ammonia to nitrogen and hydrogen, are discussed. This is particularly relevant in the presence of a high concentration of ammonium nitrate in waste (>0.5 M) with industrially relevant electrochemical performance (>300 mA/cm2 with Faradaic Efficiencies higher than 50%). The initial approach involves the integration of CuNi/C and Pt3Ir/C catalysts for reduction and oxidation, respectively [4]. The subsequent approach underscores pulsed electrodeposition of CuNi [5] for nanoparticle synthesis in the reduction process, coupled with the use of Pt3Ir/C catalyst for oxidation. The effect of different applied potentials was studied for the conversion of NO3 - to NH3 and subsequent H2 production. Electrode stability and process integration were investigated.[1] Kani, N. C., Nguyen, N. H. L., Markel, K., Bhawnani, R. R., Shindel, B., Sharma, K., Kim, S., Dravid, V. P., Berry, V., Gauthier, J. A., Singh, M. R., “Electrochemical Reduction of Nitrates on CoO Nanoclusters-Functionalized Graphene with Highest Mass Activity and Nearly 100% Selectivity to Ammonia,” Adv. Energy Mater. 2023, 13, 2204236.[2] United States Occupational Safety and Health Administration, Bureau of Alcohol, Tobacco, Firearms and Explosives, Environmental Protection Agency, "Chemical Advisory: Safe Storage, Handling, and Management of Solid Ammonium Nitrate Prills," EPA 550-F-15-001, June 2015.[3] Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP), "Conversion of Ammonium Nitrate Solutions to Useful Products," SERDP and ESTCP Website, April 5, 2021. [Online].[4] Hariri, M.B., and Botte, G.G., "Simultaneous Removal of Ammonia and Nitrate from Wastewater Using a Pulse Electrolysis Technique," Journal of The Electrochemical Society 170.5. 2023.[5] I. Baskaran, T.S.N. Sankara Narayanan, and A. Stephen, "Pulsed electrodeposition of nanocrystalline Cu–Ni alloy films and evaluation of their characteristic properties," Materials Letters, vol. 60, no. 16, pp. 1990-1995, July 2006.

Morphology‐controlled synthesis of multi‐metal‐based spinel oxide nanocatalysts and their performance for oxygen reduction

AbstractWe present a one‐pot colloidal synthesis method for producing monodisperse multi‐metal (Co, Mn, and Fe) spinel nanocrystals (NCs), including nanocubes, nano‐octahedra, and concave nanocubes. This study explores the mechanism of morphology control, showcasing the pivotal roles of metal precursors and capping ligands in determining the exposed crystal planes on the NC surface. The cubic spinel NCs, terminated with exclusive {100}‐facets, demonstrate superior electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media compared to their octahedral and concave cubic counterparts. Specifically, at 0.85 V, (CoMn)Fe2O4 spinel oxide nanocubes achieve a high mass activity of 23.9 A/g and exhibit excellent stability, highlighting the promising ORR performance associated with {100}‐facets of multi‐metal spinel oxides over other low‐index and high‐index facets. Motivated by exploring the correlation between ORR performance and surface atom arrangement (active sites), surface element composition, as well as other factors, this study introduces a prospective approach for shape‐controlled synthesis of advanced spinel oxide NCs. It underscores the significance of catalyst shape control and suggests potential applications as nonprecious metal ORR electrocatalysts.

Croton macrostachyus leaf-mediated biosynthesis of copper oxide nanoparticles for enhanced catalytic reduction of organic dyes

Introduction. Owing to the increasing use of organic dyes, the biosynthesis of metal oxide nanocatalysts is urgently needed as an economical and environmentally friendly solution to reduce their waste release. Method. In this study, we synthesized copper oxide nanoparticles (CuO NPs) by the sol–gel method using Croton macrostachyus leaf extracts as capping and reducing agents. The biosynthesized CuO catalysts were characterized using x-ray diffraction analysis (XRD), thermogravimetric differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Result. The result showed that the synthesized CuO NPs had a crystallite size of about 9 nm and had good crystalline texture. Furthermore, the catalyst showed the best catalytic reduction performance in 1 min for methylene blue (MB) and 3 min for methyl orange (MO). Furthermore, the CuO catalyst synthesized using Croton macrostachyus leaf extract resulted in apparent rate constant (Kapp) values for MB and MO of 0.06793 s−1 and 0.01877 s−1, respectively. Discussion. The recyclability of the CuO catalyst was investigated, and it was shown that the catalysts are suitable for reuse in dye reduction. Therefore, the catalytic activity of this study suggests that the CuO nanocatalysts prepared in this work are a potential candidate for controlling organic pollutants or trace amounts of naturally occurring active organic chemicals in all environmental dye wastes.

Recent advances on hydrogen generation based on inorganic metal oxide nano-catalyst using water electrolysis approach

Abstract Today world is looking for a cheap, environment friendly and efficient substitute of fossil fuel. Because due to large consumption of the fossil fuels on daily basis in whole world, emission of hazardous gases have produced lethal effects on human being. In this scenario hydrogen energy has emerged in form of clean, renewable and more efficient energy. Now the key challenge is that efficient production of the green hydrogen at commercial scale to meet demand of hydrogen. The electrolysis of water is the best pathway to achieve efficient hydrogen production. For this purpose the synthesis and improvement of low cast, active as well as stable catalysts or electrolysis is prerequisite for hydrogen production by electro-catalytic method for splitting of water. Main focus of this review is that, how we can perform the electrolysis of water by various techniques using novel methods especially electro-catalysts in term of activity, efficiency, large surface area, porosity, and stability. This will be performed by the method of two-half cell reaction one is the Hydrogen Evolution Reaction (HER) other one Oxygen Evolution Reaction (OER), where reaction proceeded in both medium acidic as well as alkaline phases. Particular attention is given to produce green clean hydrogen production from usable water and its physical and chemical storages for further uses for the support of human sustainability. Basically the recent strategy is to prepare, design and development of nanoscale materials/composite with non-noble metals and with also nanostructured with noble-metals will be discussed in this approach. The increased efficiency and utility have been the focal points of the use of diverse materials from different classes. To increase the electro-catalytic efficiency in OER and HER, we will discuss about new analyses methods and insights into studying the chemical compositions, shapes, surface area, porosity, and synergy of catalysts and the active sites of nanostructured electro-catalysts. This review will further provide the picture of current state of developments as well as recent progress for mechanized efficient production of clean hydrogen (i.e., HER) from water by electrocatalytic method using various nanoscale materials in a broad scale.

An Efficient and Magnetically Retrievable Mixed Metal Oxide Nanocatalyst for the Aqueous Media Three-Component Synthesis of Naphtho [1,2-e] [1,3] Oxazine Derivatives Under Green Conditions

Background: In recent years, the use of nanomaterials as heterogeneous catalysts has attracted much attention in organic reactions. Methods: A magnetically separable mixed metal oxide, Manganese Zinc Iron Oxide (Mn2O3/Fe3O4/ZnO) nanoparticles as nanocatalyst (Mmo@NCt) were synthesized using ultrasonic wave methods in the presence of polyethylene glycol as surfactant. In the second part of the present study, a practical procedure for the one-pot ternary condensation of aromatic aldehydes, β- naphthol, and urea in short reaction time for the synthesis of pharmaceutically interesting naphtho[ 1,2-e][1,3]oxazine derivatives using Mmo@NCt as an efficient, cost-effective and recyclable nanocatalyst under green conditions has been developed. Results: The analysis of phase purity, magnetic structure, size, and morphology of the as-synthesized nanocatalyst was characterized by X-ray diffraction, VSM, SEM, and EDX techniques. The results of SEM imaging showed that all compounds have a spherical morphological structure with a mean diameter of 16.50 ± 3.94 nm. The structure of the products was confirmed by FT-IR, 1HNMR spectroscopy, and melting point. Conclusion: This project was designed and performed with the use of magnetic nanocatalysts as a suitable method with high efficiency a shorter time for the synthesis of naphthoxazinones heterocyclic compounds due to the medicinal importance of water as a green solvent.

Zr-doped MgAl-LDH@Au nano-catalysts for selective and efficient oxidation of biomass-derived furfural

Lignocellulosic biomass upgrading is a pivotal axis in the transition from an economy based on fossil resources to one reliant on renewable biomass resources. Within this context, low-cost Zr-doped MgAl-LDH@Aunano-catalysts are reported in this study as efficient catalysts to synthesize bio-based succinic acid. A series of Zr-doped MgAl-LDH and Au/Zr-doped MgAl-LDH catalysts have been successfully prepared. All catalysts have a lamellar double hydroxide structure LDH even after enrichment with Zr and addition of Au.Au NPs have small average sizes ranging from 1.2 to 8.5 nm. The materials under study showed exalted catalytic performances in the direct synthesis of succinic acid from bio based furfural via an aqueous phase oxidation reaction with H2O2. 84 % of furfural conversion and 99 % selectivity towards succinic acid were achieved.A positive synergy between Zr and Au NPs is highlighted and related to this catalytic performances improvement.

Rhodium-decorated palladium nanocubes supported on Ni(OH)2 nanosheets/C for enhanced ethanol oxidation

This study investigates the improvement of Palladium (Pd)-based nanocatalysts for ethanol oxidation in alkaline solutions, a process often hindered by the poisoning of the catalyst’s surface. We synthesise Pd nanocubes and Rhodium (Rh)-decorated Pd nanocubes, both supported by a composite of nickel hydroxide nanosheets and carbon (Ni(OH)2/C). The developed Pd nanocatalysts possess a nanocubic morphology with smaller sizes compared to Pd/C, alongside additional nanostructures like nanorods X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses suggest that Rh decoration on Pd nanocubes prevents Pd oxidation, with Rh itself being oxidised. The electrocatalytic performance of the Rh/Pd/Ni(OH)2/C hybrid catalyst displays a notable enhancement, attributed to the combined effects of the exposed Pd (100) crystal surfaces, the addition of oxygenated species through the Ni(OH)2 component, and the deliberate addition of Rh. Comparative assessments reveal that this composite surpasses Pd/C and Pd/C nanocubes, achieving specific activities that are approximately 11.6 and 3.5 times greater, respectively. Electrochemical Impedance Spectroscopy data and chronoamperometric studies confirm superior ethanol oxidation efficiency and improved catalytic stability. These findings highlight the utility of Rh/Pd/Ni(OH)2/C nanocubes in direct ethanol fuel cells, providing promising pathways for enhancing fuel cell technologies.

Flexible bifunctional wood-derived water filtration/photo-Fenton membrane for efficient purification of mixed organic wastewater

Membrane filtration technology demonstrates excellent continuous processing capability in organic wastewater treated processes, which is usually applied in continuous industrial processes. However, it still faces a contradiction between membrane flux and treatment efficiency. In this study, a flexible wood-based photocatalytic membrane with high membrane flux and exceptional photofenton performance was developed via partial fragment wood components and uniform loading of multi-metal oxide nanocatalysts, which breaks mentioned contradiction. The homogeneous and efficient wood-based dual-function water filtration/photofenton system was established by leveraging the directional porous structure of wood in conjunction with the nanocatalysts while adjusting their ratios, enabling effective purification of highly concentrated mixed organic wastewater. Under one solar intensity and negative pressure filtration (0.03 MPa), the system treated a mixed solution containing Rhodamine B, phenol, and tetracycline at a concentration of 280 mg L−1 with the removal efficiencies of 100 %, 93.4 %, and 90.2 %, respectively, and the membrane flux could up to 315.3 Lm−2 h−1 within one hour. The membrane showed a good recycling performance, and the decay rates were all below 5 % after five cycles. This wood-based dual-function water filtration/photo-Fenton system provides a new approach for the continuous dynamic treatment of high-concentration organic wastewater on an industrial scale.

Characterization of phytosynthesized niobium oxide nanoparticle for efficient conversion of Grewia asiatica L. waste seed oil into sustainable fuel

The production of bioenergy and bioproducts from streams of biowaste has ignited interest in fostering a circular economy worldwide. This study investigates the potential of transforming Grewia asiatica L. waste seed oil into sustainable biodiesel using green-synthesized niobium oxide nanoparticle. Niobium oxide nanocatalyst was synthesized using aqueous leaf extract of Fumaria indica L. Advanced characterization techniques were employed to confirm the pure and nano-scale nature of the synthesized niobium oxide nanocatalyst. The synthesized nanocatalyst exhibited an average particle size of 31 nm, resulting in efficient catalytic activity that persited through the fifth cycle of transesterification. An optimum biodiesel yield of 90% was achieved under reaction conditions of a methanol to oil molar ratio of 9:1, a reaction time of 180 min, a temperature of 60 °C and a catalyst load of 0.32 (wt. %). Results of Gas chromatography mass spectrometry (GC–MS) analysis of G. asiatica-derived biodiesel revealed 5, 8-Octadecadienoic acid methyl ester as the primary fatty acid methyl ester, with the highest concentration. The fuel properties of G. asiatica-derived biodiesel complied with international standards. The minimal sulphur content of 0.0001% highlights the clean, environmentally benign and cost-effective nature of biodiesel synthesized from G. asiatica waste seed oil. This study contributes to the renewable alternative effort toward transitioning from a linear economy to a circular bioeconomy.

The potential of calcium oxide nanocatalyst from chicken eggshells for biodiesel production using chicken fat waste

This research aims to synthesize biodiesel using raw materials from chicken fat waste and a catalyst from eggshells (EGS). The eggshells used as a catalyst were calcined (EGS_calcined) and uncalcined (EGS_uncalcined). The calcination process was carried out at a temperature of 900 °C with a heating rate of 5 °C/minute under static air conditions for 24 h. The X-ray Diffraction diffractogram showed that the calcination process has successfully converted the calcium carbonate compound in the eggshell into calcium oxide. The particle sizes of EGS_uncalcined and EGS_calcined catalysts were 509.2 nm and 2.9 nm, respectively. Chicken fat transesterification reaction conditions were optimized to increase biodiesel yield, including variations in EGS catalyst mass (1–3 % of chicken fat extract (oil) weight), oil and methanol mole ratio (1:5–1:30), temperature (55–75 °C), and reaction time (30–180 min). The EGS catalyst mass conditions, oil and methanol mole ratio, temperature, and reaction time that produced the highest yield (93 %) were 1.5 % (w/w oil), 1:10, 65 °C, and 120 min, respectively. Research showed that the calcined EGS_catalyst performs better than the uncalcined EGS_catalyst.