Surface Of Nanosheets Research Articles

Visible Light-Driven Aerobic Oxidation of Amines Coupling with H2O2 Production Catalyzed by CoPc/Alkali Metal-Doped g-C3N4 Z-Scheme Heterojunction

Three environmentally friendly Z-scheme CoPc/alkali metal-doped g-C3N4 heterojunction composites were fabricated via in-situ immobilizing cobalt phthalocyanine (CoPc) on the surface of alkali metal-doped g-C3N4 nanosheet by simple hydrothermal method. These composites acted as efficient and recyclable heterogeneous photocatalysts realized that the highly selective aerobic oxidation of amines to the corresponding imines coupling of hydrogen peroxide generation at room temperature. Under irradiation by LED lamp, the imines and H2O2 were obtained with conversion ranges from 87.9% to 92.0%, selectivity more than 99%, and production rate ranges from 3.27 to 3.40mmolg-1 h-1, respectively. Based on the mechanistic analysis and characterization, the excellent catalytic activity derived from the Z-scheme mechanic and synergistic effect originated from O2 reduction and amine oxidation. On completion, after centrifugation, washing with solvent and drying under vacuum, the catalysts can be recovered and reused for five successive cycles of testing with a slight decrease in reactivity. For this work, a promising photo synthesis pathway with merits of mild, low-cost, pollution-free, and energy-saving was developed to produce imines coupling with H2O2 generation.

Efficient H2 evolution over MoS2-NiS2/g-C3N4 S-scheme photocatalyst with NiS2 as electron mediator

Low-cost transition metal sulfides are commonly utilized as photocatalysts for H2 production owing to their exceptional conductivity and superior specific surface area. In this study, MoS2-NiS2 nanoflowers with multidimensional space structure was obtained through the sulphuration reaction between S2- and NiMoO4 under Kirkendall effect during hydrothermal reaction. Subsequently, MoS2-NiS2 was loaded on the surface of g-C3N4 nanosheets using a solvent self-assembly strategy to form 3D MoS2-NiS2/g-C3N4 heterojunctions. The experimental results demonstrate that the H2 production rate of 20 wt% MoS2-NiS2/g-C3N4 reaches 22153 μmol·g-1·h-1 under a 300 W Xe lamp irradiation, which is 59.5 and 201.4-folds than MoS2-NiS2 and g-C3N4, and surpasses 20 wt% MoS2/g-C3N4 (211 μmol·g-1·h-1) and 20 wt% NiS2/g-C3N4 (6183 μmol·g-1·h-1). The XPS and Superoxide radical capture experiments demonstrate that the charge transfer between MoS2-NiS2 and g-C3N4 follows the S-scheme route, and NiS2 functions as an electron mediator, facilitating the transfer of electrons from MoS2 to g-C3N4 to consume the holes, which enhances the efficiency of H2 evolution reaction on g-C3N4. Furthermore, the S-scheme heterojunction of MoS2-NiS2/g-C3N4 with the multidimensional geometric structure can provide abundant active sites for catalytic reactions, this presents a promising approach for the development of cost-effective and high-performance g-C3N4-based heterojunctions. This work offers distinctive perspectives on the trajectory of renewable H2 energy development.

One-step Fabrication of Bi2MoO6 Nanowires-g-C3N4 Composites for Outstanding Photocatalytic Performance in Cyclohexane Oxidation

Selective oxidation of cyclohexane into cyclohexanone (K) and cyclohexanol (A) stands as a pivotal process in industrial chemistry. However, the challenges associated with activating the C-H bond and the vulnerability of KA oil to over-oxidation detract from the economic significance of this reaction. This study focuses on the preparation of a bismuth molybdate ultrathin nanowires-carbon nitride (Bi2MoO6-g-C3N4) heterojunction through a one-step hydrothermal approach for significantly improving the photocatalytic oxidation of cyclohexane. Bi2MoO6 ultrafine nanowires with the diameter of 6nm were adhered tightly on the surface of g-C3N4 nanosheets with the assistance of oleyl amine. The type II heterojunction of Bi2MoO6-g-C3N4 composite facilitated a more efficient separation of charges and boosted the photocatalytic performance in the cyclohexane oxidation. The Bi2MoO6-g-C3N4 composite demonstrated outstanding photocatalytic performance with a 10.66% conversion rate of cyclohexane, surpassing the individual efficiencies of Bi2MoO6 and g-C3N4 by 1.9 and 2.2 times, respectively. Moreover, it demonstrated an outstanding KA oil selectivity of 99.32%, showcasing exceptional levels of both conversion and selectivity simultaneously. Through the utilization of photoelectrochemical analysis, research on band structures, experiments on radical trapping and monitoring, we have extensively investigated the mechanism of photocatalysis. The type II charge transfer in Bi2MoO6-g-C3N4 heterojunction restricted the redox capacity of electrons in the conduction band and holes in the valence band, effectively curbing over-oxidation reactions of KA oil, thus achieving remarkable KA oil selectivity. It offers a valuable insight into the creation of heterojunctions to boost the efficiency of photocatalytic oxidation of cyclohexane, showing promise for advancing the field of photocatalysis.

Selective passivation of 2D MoS2 nanosheets surface defects by spontaneous growth of Au nanoparticles for full response-recovery NO2 detection at room temperature

Full recovery at room temperature (RT) is quite challengng for two dimensional transition metal dichalcogenides chemiresistive gas sensors. The main reason for the incomplete recovery is the strong bonding of gas molecules onto sensing layer defects. Here, we show that the recovery rate of MoS2 chemiresistive NO2 sensors can be improved by selective passivation of MoS2 nanosheets (NSs) defects with Au nanoparticles (NPs) via a simple spontaneous reduction method. MoS2 NSs were produced by liquid shear exfoliation. Pristine and Au NPs functionalized MoS2 were characterized using ς-potential, UV–Visible spectroscopy, TEM, SEM, AFM, EDS, XRD, XPS and Raman spectroscopy. The analyses confirm the presence of Au NPs on the edges of MoS2 NSs at defective sites with NP sizes of 1–4 nm and 5–30 nm. Both pristine MoS2 and Au-decorated MoS2 NSs were employed to fabricate NO2 chemiresistive devices. Au-decorated MoS2 sensors showed an improved performance (for 1 ppm NO2, Au-MoS2 sensor exhibited a response of 5.6 % instead of 2.2 % for MoS2 sensor), and gave faster response and better recovery time. Concurrently, the functionalization is independent of the adsorption and desorption of NO2. Most importantly, the functionalization of MoS2 NSs helps to full response-recovery within one hour, without either thermal or UV irradiation treatment.

Interaction of 5-Fluorouracil on the Surface of Graphene Oxide Nanosheets: Stability and Electronic Properties

Interaction of 5-Fluorouracil on the Surface of Graphene Oxide Nanosheets: Stability and Electronic Properties

Synthesis of Ecofriendly Bimetallic Pt/Ni Nanoparticles on KNbO3 via Hydrothermal Process for Sustainable Hydrogen Evolution from NaBH4

The performance of nickel and platinum bimetallic nanoparticles (NPs) supported on potassium niobate (KNbO3) is evaluated in the catalytic hydrolysis of sodium borohydride (NaBH4) to generate hydrogen (H2). KNbO3 was synthesized via a hydrothermal route using Nb2O5 and KOH as precursors. X-ray diffraction (XRD) confirmed the crystalline orthorhombic structure of KNbO3. The Ni/Pt NPs, with an average size of 4.66 nm and a spherical morphology, were uniformly dispersed on the surface of KNbO3 nanosheets. The N2 physisorption isotherms of KNbO3 and Ni/Pt NPs were classified as type V with H3 hysteresis, showing specific surface areas of 0.170 and 2.87 m2 g−1, respectively. Catalytic performance studies examined various Ni/Pt molar ratios, with the 1:3 ratio (mol/mol) demonstrating the highest efficiency. Kinetic analysis of NaBH4 hydrolysis showed that the data fit the pseudo-first-order model. An increase in temperature enhanced the hydrogen generation rate (HGR), reaching 2068.3 mL gcat−1 min−1 at 315.05 K. The apparent activation energy (Ea) was determined to be 29.9 kJ mol−1. Durability assays showed only an 11% decrease in activity after 11 catalytic cycles. Thus, a promising, easy-to-synthesize, and environmentally friendly catalyst for NaBH4 hydrolysis has been developed.

High Performance H2S Sensor Based on Ordered Fe2O3/Ti3C2 Nanostructure at Room Temperature.

The utilization of a heterogeneous nanojunction design has shown significant enhancements in the gas sensing capabilities of traditional metal oxide gas sensors. In this study, a novel room temperature H2S gas sensor employing Fe2O3 functionalized Ti3C2 MXene as the sensing material has been developed. This sensor exhibits a broad detection range (0.01-500 ppm), low detection limit (10 ppb), and rapid response/recovery times (10 s/15 s), making it ideal for ppb-level H2S detection. The exceptional gas sensitivity of Fe2O3/Ti3C2 composite to H2S can be attributed to several key factors. First, the unique layered frame structure of Fe2O3/Ti3C2 significantly amplifies the surface area of the hybrid material, enhancing the absorption and diffusion capabilities of H2S molecules. Second, the abundance of functional groups (-O, -OH, and -F) on the surface of Ti3C2 MXene nanosheets provides additional active sites for H2S adsorption, The density functional theory calculation confirms that the adsorption energy of the Fe2O3/Ti3C2 composite for H2S (-2.93 eV) is significantly lower than that of pure Fe2O3 (-2.37 eV) and Ti3C2 (-0.2 eV). Lastly, the remarkable metal conductivity of Ti3C2 MXene ensures efficient electron transfer, thereby enhancing overall sensing performance.

Field-Free Superconducting Diode Effect and Magnetochiral Anisotropy in FeTe0.7Se0.3 Junctions with the Inherent Asymmetric Barrier.

Nonreciprocal electrical transport, characterized by an asymmetric relationship between the current and voltage, plays a crucial role in modern electronic industries. Recent studies have extended this phenomenon to superconductors, introducing the concept of the superconducting diode effect (SDE). The SDE is characterized by unequal critical supercurrents along opposite directions. Due to the requirement on broken inversion symmetry, the SDE is commonly accompanied by electrical magnetochiral anisotropy (eMCA) in the resistive state. Achieving a magnetic-field-free SDE with field tunability is pivotal for advancements in superconductor devices. Conventionally, field-free SDE has been achieved in Josephson junctions by intentionally intercalating an asymmetric barrier layer. Alternatively, internal magnetism was employed. Both approaches pose challenges in the selection of superconductors and fabrication processes, thereby impeding the development of SDE. Here, we present a field-free SDE in FeTe0.7Se0.3 (FTS) junction with eMCA, a phenomenon absent in FTS single nanosheets. The field-free property is associated with the presence of a gradient oxide layer on the upper surface of each FTS nanosheet, while eMCA is linked to spin splitting arising from the absence of inversion symmetry. Both SDE and eMCA respond to magnetic fields with distinct temperature dependencies. This work presents a versatile and straightforward strategy for advancing superconducting electronics.

Sensitive Electrochemical Determination of Quercetin in Fruit Juice Using an Aluminum Hydroxide Oxide–Titanium Carbide MXene Composite

A hybrid material composed of aluminum hydroxide oxide (AlOOH) and titanium carbide (Ti3C2) nanosheets was synthesized and used for electrochemical sensing of quercetin. The Ti3C2 nanosheets were synthesized using a selective etching technique, followed by the hydrothermal growth of AlOOH on the nanosheet surfaces. Cyclic voltammetry and differential pulse voltammetry were performed to evaluate the electrochemical properties of the AlOOH@Ti3C2 nanocomposites. Under optimal conditions, the AlOOH@Ti3C2 modified electrode exhibited wide linearity and high sensitivity. The practicality of the sensor was verified through an interference study and real sample analysis. Additionally, the sensing platform exhibited outstanding operational and storage stability.

Influence of silane and polyethylene glycol functionalization of boron nitride nanosheets on mechanical and thermal properties of epoxy nanocomposites: Machine and deep learning forecasting

AbstractThe influence of hexagonal boron nitride (hBN) nanosheet surface modification on epoxy nanocomposites' mechanical and thermal properties were investigated. An innovative approach was developed for synthesizing hBN nanosheets (hBNNs) via optimized ultrasonic‐assisted liquid‐phase exfoliation (UALPE), followed by functionalization with 3‐aminopropyltriethoxysilane (APTS) and polyethylene glycol (PEG600) for nanocomposite preparation. Compared to unmodified epoxy, nanocomposites containing 0.3 wt% of pristine hBNNs exhibited significant enhancements in flexural strength (125.28 MPa) and tensile strength (53.35 MPa), with respective increases of 40.57% and 43.23%. PEG‐hBNNs improved flexural and tensile strengths to 136.83 and 58.57 MPa, respectively. The most substantial enhancements were observed with APTS‐hBNNs, yielding flexural and tensile strengths of 174.13 and 63.53 MPa, reflecting increases of 95.37% and 70.50%, attributed to better interfacial interactions and a more effective crack deflection mechanism. Thermal stability analyses revealed superior performance of modified hBNNs epoxy nanocomposites, increasing 8.2°C and 6.3°C at 50 wt% degradation as compared to the unmodified system, owing to enhanced physical barrier properties. Structural and morphological analyses validated the successful exfoliation and modification of hBNNs. Predictive models utilizing machine and deep learning (DL) techniques, particularly DL with the adaptive moment estimation (ADAM) optimizer, effectively forecasted mechanical properties, achieving high R2 values.HIGHLIGHTS 0.3 wt% modified hBNNs epoxy nanocomposite showed the highest mechanical strength Improved thermal stability of epoxy nanocomposite by modification of hBNNs Improved crack deflection mechanism in the presence of surface‐modified hBNNs Deep learning with ADAM optimizer showed high R2 and low prediction loss

Noble-metal-free Bi-OZIS nanohybrids for sacrificial-agent-free photocatalytic water splitting: With long-lived photogenerated electrons

The production of hydrogen via the hydrogen evolution reaction, reliant on the use of valuable sacrificial agents, is not conducive to large-scale photocatalytic hydrogen generation. A more pragmatic approach involves the creation of catalyst materials free from noble metals, which possess enduring photogenerated electrons suitable for catalyzing hydrogen evolution from undiluted water. In our research, x%Bi-OZIS nanohybrids were effectively synthesized. Remarkably, the hydrogen evolution rate for the 10 %Bi-OZIS sample reached 170.22 μmol g-1h−1, marking an enhancement of 11.8 times over pure ZIS and 3.7 times over OZIS, achieved without resorting to sacrificial agents. Notably, post-light exposure, H2O2 presence was identified in the water solution. The strategy of substituting some of the sulfur with oxygen doping extends the lifespan of the photogenerated carriers. Further, the introduction of Bi spheres onto the OZIS nanosheet surfaces substantially reduces electron-hole interband recombination. These adaptations collectively augment the photogenerated electron lifespan in x%Bi-OZIS nanohybrids, leading to heightened photocatalytic redox proficiency. This research outlines a method for devising an economical solar-driven water splitting mechanism devoid of sacrificial agents.

H2O2-assisted room temperature preparation of crystalline TiO2 and Ti3C2Tx-derived C-doped amorphous TiOx homojunction for photocatalytic degradation of tetracycline

The light absorption, active sites, and charge carriers separation of photocatalysts are extremely important factors in the field of photocatalysis. Near-perfect lattice-matched homojunction constructed using disorder engineering and doping strategies is an effective strategy to improve photocatalytic activity. Herein, we developed crystalline TiO2 nanoparticles (NPs) and Ti3C2Tx MXene-derived C-doped amorphous TiOx homojunction (TCT) at room temperature. In this homojunction, TiO2 NPs are evenly distributed on the surface of the C-TiOx nanosheet to form a type-II structure, which promotes the separation of photogenerated carriers. The light absorption range of TCT extends to 550 nm due to the presence of intermediate energy levels in C-TiOx, which increases its photon absorption capacity. Moreover, TCT possesses a large number of oxygen vacancies, which are beneficial for improving the adsorption and degradation of pollutants. These characteristics of TCT could significantly improve its photodegradation performance for tetracycline. Interestingly, the precursor mass ratio of TCT with the best degradation efficiency is different under different illumination conditions, which is attributed to the different band gaps of C-TiOx and TiO2 NPs resulting in different light absorption ranges. This work provides a new approach to rationally designing crystalline and amorphous homojunction for photocatalytic applications.

Photocatalytic reduction of nitroarene derivatives by impressive visible-light active Co3O4-QDs/Mn3O4 nanocomposite

A visible light active Co3O4-quantum dots (QDs)/Mn3O4 nanocomposite was successfully synthesized by a straightforward precipitation approach. Notably, the formation of Mn3O4 nanosheets in composite structure was evidenced by different physicochemical techniques especially transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and N2 sorption analyses, which indicated the uniform distribution of Co3O4-QDs with small size of around 5 nm on the surface of Mn3O4 nanosheets along with the enhancement of specific surface area for final composite. Also, the persistence of Co3O4-QDs during nanocomposite synthesis was analyzed by X-ray diffraction (XRD), FT-IR and TEM techniques. The diffuse reflectance UV–Vis and electrochemical impedance spectroscopies revealed the reduction of band gap energy and enhanced charge separation efficiency for Co3O4-QDs/Mn3O4 nanocomposite, respectively, which consequently led to improved photocatalytic response in comparison with bare Co3O4-QDs and Mn3O4 nanosheets. The as-prepared nanocomposite exhibited excellent photocatalytic activity in the reduction of a wide range of substituted nitroarenes with the yields of higher than 80 % relative to the corresponding arylamines, using N2H4·H2O as the hydrogen source and ethanol as green solvent at 25 °C and ambient pressure under visible light illumination. The synergistic effect could improve the production of active hydrogen atoms, therefore, the reasons for this transformation over the prepared nanocomposite under benign conditions are fully discussed. Furthermore, the nanocomposite could be easily recycled without decay in photocatalytic activity for at least five successive cycles.

Visible Light-Triggered Catalytic Performance of Reduced Graphene Oxide Decorated With Copper Oxide Nanocomposite for Degradation of Rhodamine B Dye and Kinetics Studies.

Herein, novel nanocomposites based on reduced graphene oxide decorated copper oxide nanoparticles (rGO/CuO) were prepared by the in situ co-precipitation method. The structural, morphological, and optical characterization of as-prepared nanocomposites was performed by powdered x-ray diffraction (p-XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR), Raman, and ultraviolet-visible (UV-Vis) spectroscopy, respectively. The as-prepared nanocomposites exhibited better photocatalytic activity of rhodamine B dye with maximum ~94% degradation in 120 min with a rate constant of 0.2353 min-1 under optimized conditions. Furthermore, the effects of solution pH and catalyst loading are studied on the degradation process. Therefore, this state-of-the-art strategy for the decoration of CuO nanoparticles onto the surface of rGO nanosheets could be an ideal platform for fabricating highly efficient photocatalysts.

Microwave-assisted hydrothermal synthesis of highly dispersed cerium–zirconium solid solution on Ti3C2Tx nanosheets as an efficient decontamination towards sulfur mustard simulants

The microwave-assisted hydrothermal method has facilitated the straightforward and efficient production of nanoscale CexZr1-xO2/Ti3C2Tx composites. This technique has greatly shortened the synthesis time several hours required by conventional hydrothermal method to merely 10minutes. Due to the unique mechanism of microwave-hydrothermal synthesis, composites with excellent crystallinity, uniform particle size, and superior degradation capabilities can be obtained without calcination. Our investigation systematically explores the influence of various factors including mineralizer concentration, dispersant types, synthesis duration, cerium-to-zirconium ratio, as well as MXene content on the material properties. Optimal degradation of 2-chloroethyl ethyl sulfide, sulfur mustard simulants, is achieved using PEG1000 as the dispersant, a cerium-to-zirconium ratio of 1:2, along with 15mL of MXene, resulting in a remarkably short half-life of only 6.5min. Furthermore, it is confirmed that the incorporation of cerium atoms into ZrO2 lattice, forming a solid solution that is deposited onto the interlayer and surface of Ti3C2Tx nanosheets, with the composite particles measuring approximately 5.01nm. The reduced size and increased specific surface area, coupled with the synergistic effects of oxygen vacancies and acid-base sites, ultimately contribute to the hydrolysis and elimination reactions occurring on 2-CEES. This research offers fresh perspectives on the development of novel materials for the degradation of chemical warfare agents.

In-situ exfoliating graphene to anchor Mo2C NPs and modulate crystal planes for hydrogen production

An economical and efficient noble metal-free catalyst is necessary for large-scale hydrogen production. Here, Mo2C nanoparticles (NPs) were well-dispersed on the surface of 2D graphene nanosheets by in-situ propping oxide graphene (GO) layers, anchoring molybdate ions between GO layers and pyrolysis. The exposed crystal planes were also adjusted by above strategy. The results indicate that uniform and well-dispersed Mo2C NPs with a narrow size distribution were anchored on 2D rGO nanosheets and exposed dual crystal planes. The results of hydrogen evolution reaction (HER) show that the optimal Mo2C/rGO catalyst only needs low overpotential (η10, 112 mV) to drive 10 mA cm−2 in alkaline solution, and η10 only increased by 12 mV after 1000 cycles test, indicating high activity and stability for HER. Notably, the overpotential is below than that of Pt/C commercial catalyst when current density is more than 100 mA cm−1. The excellent performance is benefit from low hydrogen adsorption Gibbs free energy (ΔGH∗) on the Mo2C catalyst. Therefore, the proposed strategy is efficient to prepare well-dispersed and dual crystal planes-exposed Mo2C NPs for electrocatalytic hydrogen evolution.

Interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with metallic Fe/Al[sbnd]N bonds for efficient photocatalytic degradation of tetracycline hydrochloride

To improve the photogenerated electron–hole separation efficiency and the number of reactive oxygen species of g-C3N4 in visible light. Herein, an interface-engineered Ni(Fe/Al)-LDHs/g-C3N4 nanosheets with Fe/AlN bonds were prepared, which shows highly enhanced photocatalytic degradation performance with excellent structural stability. The interfacial structure of g-C3N4 was precisely regulated by metal Fe/Al on the surface of layered double hydroxides (LDHs), which could form Fe/AlN bonds as the interfacial charge transfer channels. In addition, the metal Ni and Fe/Al on the surface of LDHs nanosheets can furnish more photocatalytic active sites and interface synergy. The obtained 7 %NiFe-LDHs/g-C3N4 owns the degradation rate of 99.23 % for tetracycline hydrochloride (TCH) in visible light. This work highlights a rational interface engineering strategy for the formation of a composite structure with interface interaction for efficient photocatalysts.

Stable and reversible zinc metal anode with fluorinated graphite nanosheets surface coating

A highly stable zinc metal anode modified with a fluorinated graphite nanosheets (FGNSs) coating was designed. The porous structure of the coating layer effectively hinders lateral mass transfer of Zn ions and suppresses dendrite growth. Moreover, the high electronegativity exhibited by fluorine atoms creates an almost superhydrophobic solid−liquid interface, thereby reducing the interaction between solvent water and the zinc substrate. Consequently, this leads to a significant inhibition of hydrogen evolution corrosion and other side reactions. The modified anode demonstrates exceptional cycling stability, as symmetric cells exhibit sustained cycling for over 1400 h at a current density of 5 mA/cm2. Moreover, the full cells with NH4V4O10 cathode exhibit an impressive capacity retention rate of 92.2% after undergoing 1000 cycles.

Measuring the Surface Energy of Nanosheets by Emulsion Inversion.

Solution-processed nanomaterials can be assembled by a range of interfacial techniques, including as stabilizers in Pickering emulsions. Two-dimensional (2D) materials present a promising route toward nanosheet-stabilized emulsions for functional segregated networks, while also facilitating surface energy studies. Here, we demonstrate emulsions stabilized by the 2D materials including the transition metal carbide MXene, titanium carbide (Ti3C2T x ), and develop an approach for in situ measurement of nanosheet surface energy based on emulsion inversion. This approach is applied to determine the influence of pH and nanosheet size on surface energy for MXene, graphene oxide, pristine graphene, and molybdenum disulfide. The surface energy values of hydrophilic Ti3C2T x and graphene oxide decrease significantly upon protonation of usually dissociated functional groups, facilitating emulsion stabilization. Similarly, pristine graphene and molybdenum disulfide increase in surface energy when their surface functional groups are deprotonated under basic conditions. In addition, the surface energies of these pristine materials are correlated with nanosheet size, which allows for the calculation of the basal plane and edge surface energies of pristine nanosheets. This understanding of surface energies and control of emulsion inversion will allow design of emulsion-templated structures and surface energy studies of a wide range of solution-processable nanomaterials.

Study of Low Temperature-Treated Aldolized Cellulose Nanocrystals for Enhancing Dye Separation and Self-Healing Properties of Graphene Oxide Membranes.

Graphene oxide (GO) membranes with a 2D layered structure and nanoscale channels have great application prospects for dye wastewater purification. In this paper, ethylenediamine (EDA) was grafted onto the surface of GO nanosheets at 70 °C and aldolized cellulose nanocrystals (ICNC) were introduced to form EDA-ICNC hydrogel structures between the GO nanosheets by Schiff base reaction. The interlayer structure of the membrane was determined by adjusting the amount of ICNC added and the degree of aldolization, and the EGOICNC-24 membrane with the best performance was prepared. The water flux is not only 12 times higher than that of GO membrane but also has a good separation ability for dye molecules with a molecular weight around 300. Following the EDA-ICNC-24 hydrogel cross-linking process, the tensile strength of the EGOICNC-24 membrane exhibited a 173% increase relative to that of the GO membrane. Additionally, the dye rejection rate reached 97.16% after 130 h of dye separation. When the surface of the membrane was damaged, it was self-healed by regulating the repair temperature and adding a very small amount of ICNC to undergo a dynamic Schiff base reaction and a synergistic effect of hydrogen bonding.