Precursor Material Research Articles

Simultaneous synthesis of carbon quantum dots and hydrothermal biochar from corn straw through hydrothermal treatment

In the realm of efficient agricultural production, the conversion of large volumes of agroforestry waste into sustainable, high-value materials is imperative to address pollution, curb carbon dioxide emissions, and alleviate the burden of costly waste disposal. This study endeavored to address these challenges by concurrently synthesizing carbon quantum dots fluorescent nanomaterials and hydrothermal biochar through hydrothermal carbonization (HTC), employing corn straw (CS) as the primary precursor material. The synthesized CS-based carbon quantum dots (CS-CDs) exhibited a typical graphite structure, with a uniform particle size distribution and a particle size average of 2.28 ± 0.5 nm. Notably, CS-CDs displayed excitation-dependent photoluminescence (PL) behavior, remarkable water solubility, high fluorescence stability, and specific recognition capabilities for Fe3+ detection. The detection range of CS-CDs for Fe3+ spanned from 50 to 2000 μM, with a limit of detection (LOD) of 5.32 μM. Meanwhile, during the HTC process, the solid fraction yielded hydrothermal biochar (HC) at a rate of 57.60 %. HC was enriched with essential elements and held promise as an organic carbon fertilizer or premium-quality fuel, thereby realizing the multifaceted utilization potential of CS resources. This study offers valuable insights and innovative strategies for the high-value and multifunctional utilization of agroforestry resources, contributing to the promotion of sustainable agricultural practices.

Review of: "focused ion beam nanolithography requires a gas injection system to produce a local deposition from a precursor material that is delivered in the form of gas, with precursor separation created by appropriate radiation in nanoelectrical devices."

Review of: "focused ion beam nanolithography requires a gas injection system to produce a local deposition from a precursor material that is delivered in the form of gas, with precursor separation created by appropriate radiation in nanoelectrical devices."

Carbon Fibers Based on Cellulose–Lignin Hybrid Filaments: Role of Dehydration Catalyst, Temperature, and Tension during Continuous Stabilization and Carbonization

Lignocellulose has served as precursor material for carbon fibers (CFs) before fossil-based polymers were discovered as superior feedstock. To date, CFs made from polyacrylonitrile have dominated the market. In search of low-cost carbon fibers for applications with medium strength requirements, cellulose and lignin, either as individual macromolecule or in combination, have re-gained interest as renewable raw material. In this study, cellulose with 30 wt% lignin was dry-jet wet-spun into a precursor filament for bio-based carbon fibers. The stabilization and carbonization conditions were first tested offline, using stationary ovens. Diammonium sulfate (DAS) and diammonium hydrogen phosphate were tested as catalysts to enhance the stabilization process. Stabilization is critical as the filaments’ strength properties drop in this phase before they rise again at higher temperatures. DAS was identified as a better option and used for subsequent trials on a continuous carbonization line. Carbon fibers with ca. 700 MPa tensile strength and 60–70 GPa tensile modulus were obtained at 1500 °C. Upon further carbonization at 1950 °C, moduli of >100 GPa were achieved.

High performance illitic clay-based geopolymer: Influence of thermal/mechanical activation on strength development

The scientific community's interest in geopolymers keeps on growing under environmental and climate change pressures. Although most studies concern metakaolin or industrial by-products as aluminosilicate precursors, few are those concerning clay cuttings characterized by little or no kaolinite content. This study proposes a method to activate illitic clay in order to obtain a geopolymer with high mechanical performances. The tested illitic material contained 53 wt% of illite/muscovite, 22 wt% quartz, 7 wt% feldspars and low content of calcite. The innovation consists in coupling thermal and mechanical activations favoring both the clay dehydroxylation and the destruction of the clay crystalline structure. Such increase of amorphous rate in the precursor is required to make the material reactive. The evolution of the precursor material after activation was followed by ThermoGravimetric Analysis (TGA/DTG), X-Ray Diffraction (XRD), Fourier-Transform InfraRed spectroscopy (FTIR) and Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectrometry (SEM-EDX). The impact of the variations of the mechanical activation duration and ball:powder mass ratio (b:p) were mainly explored, as well as the Liquid:Solid mass ratio (L:S) which is a key parameter of the geopolymerization. Finally, an optimized geopolymer with a mechanical compressive strength reaching 126 MPa after 28 days has been manufactured with a grinding duration of 240 min, a b:p = 15 and a L:S = 0.5. The demonstration was done that a geopolymer can be manufactured from 100% illitic clay precursor, in addition to a relatively low amount of alkaline solution (L:S mass ratio of 0.5) then lowering the cost and the environment impact of the final geopolymer material. The resulting illitic clay based geopolymers can display very high mechanical resistance (compressive strength up to 126 MPa after 28 days), fully competitive with conventional building materials.

Modification of electron transfer paths in CdS-TiO2 Z-type heterojunction by cobalt-based complexes for boosting visible-light photocatalytic hydrogen evolution

Ti-oxo clusters as photocatalytic heterojunction precursor materials are a promising strategy for preparing TiO2. Enhancing the utilization of photogenerated electrons and increasing the delivery channel of these electrons can improve the performance of photocatalytic materials for H2 evolution significantly. Hereby, a novel ternary [TiO2-CdS QDs-5/Co(bpy)3Cl2] photocatalyst for highly efficient photocatalytic HER was reported for the first time. In this paper, a TiO2-CdS QDs-5 binary Z-type heterojunction was identified, and the photocatalytic HER yield was further improved by [Co(bpy)3Cl2]. The above-mentioned ternary system is advantageous for separating and transferring photogenerated electron-hole pairs. The photocatalytic HER rate of this catalytic system was 4440.84 μmol·h−1·g−1, which was 7.1 times more than that of TiO2-CdS QDs-5. The results indicate that the system is capable of maintaining stability and enhancement of the photocatalytic HER under visible light irradiation. In this study, we investigated photogenerated electron transfer pathways to improve the photocatalytic HER of TiO2 and we also revealed the electron transfer mechanism of TiO2-CdS QDs-5 Z-typed heterojunction with [Co(bpy)3Cl2] through DFT calculation. More importantly, this study presents a novel Z-type heterojunction catalyst, which enhance the electron transport path and this work provides an effective design concept for the development of TiO2-based materials for efficient photocatalytic HER.

Fabrication of biocarbon catalyst for ORR by modulating the cellulose fraction of wheat stalk

Direct Methanol fuel cells (DMFC) have been limited in their utilization due to their slow cathodic oxygen reduction reaction (ORR) kinetics and the expensive cost of commercial Pt/C catalysts. It is critical to design an oxygen reduction process with high-efficiency catalysts. An approach for modulating the ratio of cellulose, hemicellulose, and lignin in the wheat stalk (WS)/wheat stalk binder (WS binder) precursor materials is proposed in this work. WS binder from alkalization and hydrothermal treatment was added to the WS to change the structure and shape of WS-based carbon materials by varying the ratios, which increased the ORR catalytic activity. The half-wave potential (E1/2) of the produced carbon material (15 wt% N/C (WS)) is 0.76 V, which was enhanced by 80 mV by adjusting the ratio of the WS/WS binder compared to 0 wt% N/C(WS). The E1/2 of 15 wt% Fe–N/C (WS) (0.85 V) was greater than that of commercial Pt/C (0.84 V). Besides, its catalytic oxygen reduction process was close to the 4-electron transfer pathway and had good methanol tolerance. The power density obtained with a cathode catalyst of 15 wt% Fe–N/C (WS) for DMFC was 1.39 mW cm−2 at 30 °C and 3.33 mW cm−2 at 60 °C. At different temperatures, the power densities were 1.59 and 1.54 times greater than those of commercial Pt/C catalysts, respectively.

Intercalation based synthesis of Chevrel phase superconductors

This work focuses on the superconducting and magnetic properties of Chevrel phase (CP) compounds (Cu2Mo6S8 and Ni2Mo6S8) processed via a novel self-propagating high-temperature synthesis (SHS) method involving ternary cation intercalation in MoS2 high-temperature polymorphs. Green pellets of the precursor materials sealed under vacuum and exposed to 1050 °C or 1200 °C rapidly transformed from a powder mixture into submicron CPs within minutes. X-ray diffraction analysis confirmed the presence of Cu2Mo6S8 CP (67%), and Ni2Mo6S8 (93%). This group has illustrated the first time CP were formed at low energy cost and full stoichiometry. Magnetization versus temperature data obtained for the samples under different field conditions confirmed the superconducting behavior of the Cu–CP at a critical temperature of 8.3 K. The Ni–CP behaved as a superparamagnetic at low temperature (4.2 K). The results of this work suggest that the novel SHS process offers a viable scalable synthesis route for the Chevrel family of compounds and that it is worth exploring the functional applications of the new compounds of this material system.

Influence of Carbonisation Temperatures on Multifunctional Properties of Carbon Fibres for Structural Battery Applications

AbstractCarbon fibres are multifunctional materials considered for the realisation of structural battery electrodes. Processing conditions affect the carbonaceous microstructure of carbon fibres. The microstructure dictates the fibre‘s mechanical properties, i. e. modulus and strength, as well as its electrochemical capacity. Here, carbon fibre processing conditions are investigated to identify the effect of carbonisation temperature on carbon fibre multifunctionality. Different thermal conditions during carbonisation are considered, while keeping the precursor material, applied tension, and oxidation temperature constant. The carbonaceous microstructure of fibres is investigated via wide‐angle x‐ray scattering (WAXS) and transmission electron microscopy (TEM) analyses to determine the effect of the carbonisation temperature. Mechanical and electrochemical tests are performed to characterise carbon fibre multifunctionality with respect to mechanical and electrochemical performance. A moderate trade‐off between mechanical and electrochemical performance is demonstrated, where the elastic modulus and strength decrease and the electrochemical capacity increase with reduced carbonisation temperature. Here, for the studied temperature interval, the elastic modulus and strength is found to drop up to 7 % with a 15 % increase in capacity. Thus, fibres customised for targeted multifunctionality within a limited design space can be realised by careful selection of the processing conditions in conventional carbon fibre manufacture.

Composite Ionogel Electrodes for Polymeric Solid-State Li-Ion Batteries.

Realizing rechargeable cells with practical energy and power density requires electrodes with high active material loading, a remaining challenge for solid-state batteries. Here, we present a new strategy based on ionogel-derived solid-state electrolytes (SSEs) to form composite electrodes that enable high active material loading (>10 mg/cm2, ~9 mA/cm2 at 1C) in a scalable approach for fabricating Li-ion cells. By tuning the precursor and active materials composition incorporated into the composite lithium titanate electrodes, we achieve near-theoretical capacity utilization at C/5 rates and cells capable of stable cycling at 5.85 mA/cm2 (11.70 A/g) with over 99% average Coulombic efficiency at room temperature. Finally, we demonstrate a complete polymeric solid-state cell with a composite anode and a composite lithium iron phosphate cathode with ionogel SSEs, which is capable of stable cycling at a 1C rate.

Supermolecule polymer derived of carbon nitride with controllable nanosheet for enhancing the degradation performance of RhB and BPA

Using melamine-cyanuric acid (MCA) supramolecular polymer as a precursor, a method was employed to synthesize graphitic carbon nitride with a large specific surface area and controllable band structure. The band structure and morphology of graphitic carbon nitride (g-C3N4) are closely related to the type of solvent used. By treating it with hypophosphorous acid and subsequent high-temperature treatment for 10 h , the precursor material was calcined to produce graphitic carbon nitride with a hollow tubular morphology. Experimental results demonstrate that this material exhibits outstanding performance in photocatalytic degradation of Rhodamine B and Bisphenol A. This work provides a new and effective strategy for achieving visible-light photocatalytic degradation of organic compounds.

Synthesis of CBO (Co3O4-Bi2O3) Heterogeneous Photocatalyst for Degradation of Fipronil and Acetochlor Pesticides in Aqueous Medium

The excessive use of pesticides has led to the harmful contamination of water reservoirs. Visible-light-driven photocatalysis is one of the suitable methods for the removal of pesticides from water. Herein, the development of CBO (Co3O4-Bi2O3) as a heterogeneous catalyst for the visible light-assisted degradation of Fipronil and Acetochlor pesticides is reported. After synthesis via coprecipitation using cobalt (II) nitrate hexahydrate (Co(NO3)2·6H2O), bismuth (III) nitrate pentahydrate (Bi(NO3)3·5H2O) and sodium hydroxide (NaOH) as precursor materials, the prepared CBO was characterized using advanced techniques including XRD, EDS, TEM, SEM, FTIR, and surface area and pore size analysis. Then, it was employed as a photocatalyst for the degradation of Fipronil and Acetochlor pesticides under visible light irradiation. The complete removal of Fipronil and Acetochlor pesticides was observed over CBO photocatalyst using 50 mL (100 mg/L) of each pesticide separately within 120 min of reaction. The reaction kinetics was investigated using a non-linear method of analysis using the Solver add-in. The prepared CBO exhibited a 2.8-fold and 2-fold catalytic performance in the photodegradation of selected pesticides than Co3O4 and Bi2O3 did, respectively.

Inverse Vulcanization of Activated Norbornenyl Esters – A Versatile Platform for Functional Sulfur Polymers

Elemental sulfur has shown to be a promising alternative feedstock for development of novel polymeric materials with high sulfur content. However, the utilization of inverse vulcanized polymers is restricted by the limitation of functional comonomers suitable for an inverse vulcanization. Control over properties and structure of inverse vulcanized polymers still poses a challenge to current research due to the dynamic nature of sulfur‐sulfur bonds and high temperature of inverse vulcanization reactions. In here, we report for the first time the inverse vulcanization of norbornenyl pentafluorophenyl ester (NB‐PFPE), allowing for post‐modification of inverse vulcanized polymers via amidation of reactive PFP esters to yield high sulfur content polymers under mild conditions. Amidation of the precursor material with three functional primary amines (α‐amino‐ω‐methoxy polyethylene glycol, aminopropyl trimethoxy silane, allylamine) was investigated. The resulting materials were applicable as sulfur containing poly(ethylene glycol) nanoparticles in aqueous environment. Cross‐linked mercury adsorbents, sulfur surface coatings, and high‐sulfur content networks with predictable thermal properties were achievable using aminopropyl trimethoxy silane and allylamine for post‐polymerization modification, respectively. With the broad range of different amines available and applicable for post‐polymerization modification, the versatility of poly(sulfur‐random‐NB‐PFPE) as a platform precursor polymer for novel specialized sulfur containing materials was showcased.

Inverse Vulcanization of Activated Norbornenyl Esters-A Versatile Platform for Functional Sulfur Polymers.

Elemental sulfur has shown to be a promising alternative feedstock for development of novel polymeric materials with high sulfur content. However, the utilization of inverse vulcanized polymers is restricted by the limitation of functional comonomers suitable for an inverse vulcanization. Control over properties and structure of inverse vulcanized polymers still poses a challenge to current research due to the dynamic nature of sulfur-sulfur bonds and high temperature of inverse vulcanization reactions. In here, we report for the first time the inverse vulcanization of norbornenyl pentafluorophenyl ester (NB-PFPE), allowing for post-modification of inverse vulcanized polymers via amidation of reactive PFP esters to yield high sulfur content polymers under mild conditions. Amidation of the precursor material with three functional primary amines (α-amino-ω-methoxy polyethylene glycol, aminopropyl trimethoxy silane, allylamine) was investigated. The resulting materials were applicable as sulfur containing poly(ethylene glycol) nanoparticles in aqueous environment. Cross-linked mercury adsorbents, sulfur surface coatings, and high-sulfur content networks with predictable thermal properties were achievable using aminopropyl trimethoxy silane and allylamine for post-polymerization modification, respectively. With the broad range of different amines available and applicable for post-polymerization modification, the versatility of poly(sulfur-random-NB-PFPE) as a platform precursor polymer for novel specialized sulfur containing materials was showcased.

Multi-objective optimization of ternary geopolymers with multiple solid wastes

The design of the mixtures of ternary geopolymers is challenging due to the need to balance multiple objectives, including cost, strength, and carbon emissions. In order to address this multi-objective optimization (MOO) problem, machine learning models and the NSGA-II algorithm are employed in this study. To train the machine learning models, namely Artificial Neural Network (ANN), Support Vector Regressor, Extremely Randomized Tree, and Gradient Boosting Regression, 120 mixtures with uniaxial compressive strength (UCS) values of ternary geopolymers with fly ash (FA), granulated blast furnace slag (GBFS) and steel slag (SS) as precursor materials were obtained from laboratory tests. Results show that the ternary geopolymer with the ratio of FA:GBFS:SS of 2:5:3 has the highest 28-d UCS of 46.8 MPa. The predictive accuracy of the ANN model is the highest with R = 0.949 and RMSE=3.988 MPa on the test set. Furthermore, the Shapley Additive Explanations analysis indicates that precursor materials exhibit the most significant influence on the UCS, with the content of GBFS being particularly influential. Based on the ANN model and NSGA-II algorithm, a multi-objective optimization (MOO) model is developed to optimize simultaneously the strength, cost and carbon emission of the ternary geopolymer. The derived MOO model can be used to design mixtures of other cementitious materials with multiple objectives.

Selenium-doped porous-C3N4 decorated with Cu NPs, as an operative heterogenous catalyst for the nitroarenes reduction reaction

In this project, the insitu selenium-doped porous graphitic carbon nitride, named as Se-p-C3N4 was synthezied using melamine, ammonium chloride, and selenium dioxide as the low-cost precursor materials via a facil thermal condensation protocol and applied as an superlative support with high specific surface area (125.3 m2/g). Cu NPs were coorporated on the surface of Se-p-C3N4 over the co-reduction protocol with Hydrazine Hydrate as a reducing agant to prepare the Se-p-C3N4/Cu nanocatalyst. Several chemophysical analysis confirmed the structure of Se-p-C3N4/Cu. The Se-p-C3N4/Cu was showen the exceptional catalytic proficiency in the hydrogenation of nitroaromatic compounds utilizing a green redactant in an environmentally friendly aqueous media, and the related anilines were produced as sole products. The supreme catalytic effeciency and durability of the Se-p-C3N4/Cu can be attributed to the synergetic collaboration between the highly distributed Cu NPs and the support.

Synthesis and Characterization of Composite WO3 Fibers/g-C3N4 Photocatalysts for the Removal of the Insecticide Clothianidin in Aquatic Media.

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional photocatalysts (e.g., TiO2, ZnO, etc.) that utilize only UV light for activation, the interest of the scientific community has recently focused on the development and application of visible light-activated photocatalysts like g-C3N4. However, some disadvantages of g-C3N4, such as the high recombination rate of photogenerated charges, limit its utility. In this light, the present study focuses on the synthesis of WO3 fibers/g-C3N4 Z-scheme heterojunctions to improve the efficiency of g-C3N4 towards the photocatalytic removal of the widely used insecticide clothianidin. The effect of two different g-C3N4 precursors (urea and thiourea) and of WO3 fiber content on the properties of the synthesized composite materials was also investigated. All aforementioned materials were characterized by a number of techniques (XRD, SEM-EDS, ATR-FTIR, Raman spectroscopy, DRS, etc.). According to the results, mixing 6.5% W/W WO3 fibers with either urea or thiourea derived g-C3N4 significantly increased the photocatalytic activity of the resulting composites compared to the precursor materials. In order to further elucidate the effect of the most efficient composite photocatalyst in the degradation of clothianidin, the generated transformation products were tentatively identified through UHPLC tandem high-resolution mass spectroscopy. Finally, the detoxification effect of the most efficient process was also assessed by combining the results of an in-vitro methodology and the predictions of two in-silico tools.

Sulfuric acid leaching of ferronickel and preparation of precursor materials for power batteries: Strategy of enhanced leaching through thermal activation and its mechanism

With the development of the new energy industry, the demand for iron phosphate and nickel–cobalt hydroxide precursor materials in the power battery industry has increased sharply. Ferronickel with low content of other impurities, derived from electric furnace smelting of laterite nickel ore, contains iron, nickel, and cobalt components used for the production of two kinds of power batteries. In this study, the sulfuric acid leaching behaviors of the water quenched ferronickel particles under atmospheric pressure was investigated. Practically, the direct leaching performance of these ferronickel particles in sulfuric acid is unsatisfactory. The leaching of Ni, Co and Fe was only 4.52 %, 3.58 % and 3.83 %, respectively, at the initial acid concentration of 3 mol/L, liquid–solid ratio of 12 mL/g, leaching temperature of 95 °C and time of 4 h. However, through thermal activation, the face-centered cubic (FCC) Fe-Ni phase was transformed into the body-centered cubic (BCC) structure, which significantly improved its acidic leaching activity. Under the thermal activation at 800 °C for 2 h, the leaching of Ni, Co and Fe reached 91.27 %, 90.12 % and 89.19 %, respectively, at the same leaching conditions. After oxidizing the Fe(II) in lixivium to Fe(III) using hydrogen peroxide, 89.3 % of Fe was selectively precipitated into battery-grade iron phosphate by adding phosphoric acid and coordinating solution pH. Nickel and cobalt in residual solution was then recovered to nickel–cobalt hydroxide by precipitation after removing impurity ions in advance. This study provides a new pathway for the value-added utilization of ferronickel in the power battery industry, not only in the production of stainless steel.

Structural, electrical and magnetic studies on CoFe2O4 nanoparticles with polyvinylalcohol (PVA) via Sol-Gel approach

Cobalt ferrite (CoFe2O4) nanoparticles were synthesized using sol–gel method from cobalt nitrate; iron nitrate as precursor materials with the chelating agent PVA in water (2.5, 5.0, 7.5, 10.0 and 12.5 %) is added. Through X-ray diffraction (XRD) examinations, the crystallite size and single phase of the ferrite samples were studied. The functional and active analysis is found through Fourier transform infrared (FTIR) studies. The optical analysis carried out through UV–visible spectrometer and the absorption is found. The surface features and its content of elements were analyzed through SEM with EDAX analysis. The larger saturation magnetization at 12.5 % were recorded through vibrating sample magnetometer (VSM). The dielectric behavior recorded at room temperature from LCR measurement. The electrochemical behavior like V/I, impedance, scan rate and phase angle obtained through cyclic voltameter setup. The observed results with all the physical parameters with the influence of presence of PVA are discussed and interpreted extensively.

Aligned Permanent Magnet Made in Seconds–An In Situ Diffraction Study

AbstractThe synthesis of a strontium hexaferrite magnet is studied using in situ synchrotron powder X‐ray diffraction (PXRD) with a 16‐ms time resolution. The precursor material is cold compacted shape‐controlled goethite and strontium carbonate. The time evolution of the phases is modeled with sequential Rietveld refinements revealing that strontium hexaferrite forms within seconds at ≈1173 K. Texture analysis is performed on selected PXRD frames throughout the experiment, and the preferred orientation introduced by cold‐pressing goethite prevails through the iron oxide phase transitions (goethite → hematite → strontium hexaferrite). Electron backscatter diffraction (EBSD) data on the final pellet confirms the preferred orientation observed with PXRD. The resulting magnet has respectable magnetic properties, considering the simplicity of the preparation method, with an energy product (BHmax) of 18.6(8) kJ m−3.

Portable sensing methods based on carbon dots for food analysis.

Food analysis is significantly important in monitoring food quality and safety for human health. Traditional methods for food detection mainly rely on benchtop instruments and require a certain amount of analysis time, which promotes the development of portable sensors. Portable sensing methods own many advantages over traditional techniques such as flexibility and accessibility in diverse environments, real-time monitoring, cost-effectiveness, and rapid deployment. This review focuses on the portable approaches based on carbon dots (CDs) for food analysis. CDs are zero-dimensional carbon-based material with a size of less than 10nm. In the manner of sensing, CDs exhibit rich functional groups, low biotoxicity, good biocompatibility, and excellent optical properties. Furthermore, there are many methods for the synthesis of CDs using various precursor materials. The incorporation of CDs into food science and engineering for enhancing food safety control and risk assessment shows promising prospects.