Good Dispersion Research Articles

Building Chemical Interface Layers in Functionalized Graphene Oxide/Rubber Composites to Achieve Enhanced Mechanical Properties and Thermal Control Capability of Tires.

With the rapid development of the transport industry, there is a higher demand for environmental friendliness, durability, and stability of tires. Rubber composites with excellent mechanical properties, abrasion resistance, and low heat generation are very important for the preparation of green tires. In this study, the all-aqueous phase process was initially employed to prepare 2-Amino-5-mercapto-1,3,4-thiadiazole (AZT) functionalized graphene oxide (AGO). Subsequently, modified graphene oxide/silica/natural rubber (AGO/SiO2/NR) composites were obtained through latex blending and hot press vulcanization processes. This method was environmentally friendly and exhibited high modification efficiency. Benefiting from the good dispersion of AGO in the latex and the cross-linking reaction between AGO and NR, AGO/SiO2/NR composites with good dispersion and enhanced interfacial interaction were finally obtained. AGO/SiO2/NR composites showed significantly improved overall performance. Compared to GO/SiO2/NR composites, the tensile strength (28.1 MPa) and tear strength (75.3 N/mm) of the AGO/SiO2/NR composites were significantly increased, while the heat build-up value (10.4 °C) and DIN abrasion volume (74.9 mm3) were significantly reduced. In addition, the steady-state temperature field distribution inside the tire was visualized by ANSYS finite element simulation. The maximum temperature of the prepared AGO/SiO2/NR was reduced by 18.2% compared to that of the GO/SiO2/NR tires. This strategy is expected to provide a new approach for the development of low energy consumption, environmentally friendly, and long-life rubber for tires.

Piezoresistive properties of well-dispersed carbon nanotubes (CNTs) modified cement paste

When developing smart cement-based sensors with carbon nanotubes (CNTs) as conductive fillers, CNTs with good dispersion can enhance the conductivity and piezoresistive properties of cement-based materials. In this study, a combination of sonication and dispersant was used to disperse CNTs, and then investigated the piezoresistive properties of well-dispersed CNTs modified cement paste. The experimental results showed that the dispersant used was polyvinylpyrrolidone (PVP), and when the mass ratio of PVP to CNTs was 4:1, the sonication time was 25 min, and the standing time did not exceed 3 h, CNTs had higher dispersion quality. The resistivity of the cement paste decreased by two orders of magnitude with increasing CNTs dosage and exhibited visible percolation phenomenon with percolation thresholds ranging from 0.1 % to 0.3 %. The fractional change in resistivity, stress sensitivity and strain sensitivity of cement paste under cyclic loading reached the maximum values of 10.95 %, 1.146 %/MPa and 123.450 %, respectively, with high repeatability (92.63 %) and low hysteresis (8.40 %) when the content of CNTs was 0.4 %. At the same time, CNTs improved the microstructure of the cement paste, which positively affected the mechanical, electrical conductivity and piezoresistive properties of the material.

A facile approach for enhancing mechanical resilience, and corrosion protection in epoxy coatings using bismuthene nanosheets

AbstractThis study presents novel mechanochemical methods for the synthesis and chemical modification of bismuthene nanosheets (BINS) using a high‐speed blender and planetary ball milling. Atomic force microscopy (AFM) measurements confirmed successful exfoliation of 1.5‐nm BINS. Epoxy/BINS nanocomposites exhibited enhanced mechanical properties, thermal stability, and chemical resistance. Chemical modification via ball milling improved the interface and dispersion of BINS within the epoxy matrix, leading to significant enhancements in mechanical performance and chemical resistance. Compared to neat epoxy, at 0.75 vol% m‐BINS, Young's modulus, impact strength and fracture toughness KIC were respectively enhanced by 30%, 88.6%, and 144.4% while these increments were 10%, 55.7%, and 97.8% for pristine BINS‐based epoxy nanocomposite. A 3D finite element model of the impact test of the nanocomposite was developed to predict its behavior under high‐strain rate loadings; the numerical model showed high agreement with experimental measurements. Epoxy/m‐BINS nanocomposites demonstrated exceptional chemical resistance, attributed to the small lateral dimensions of m‐BINS, which fill the spaces between cross‐linked epoxy molecules and uniformly distribute within the matrix. These findings highlight the crucial role of interface and dispersion in defining the mechanical properties of nanocomposites. Overall, this study provides a facile and scalable method for synthesizing and modifying bismuthene, showcasing its potential for developing functional polymer nanocomposites.Highlights Bismuthene nanosheets & modified BINS (m‐BINS) are prepared by eco‐friendly method. m‐BINS is ~1.5 nm thick and ~0.5 μm wide. m‐BINS shows good dispersion and strong interface adhesion within epoxy matrix. Impact strength and KIC of epoxy/m‐BINS nanocomposite are enhanced by 88.6% and 144.4%. Numerical model for impact strength is developed to predict behavior at high‐strain rate.

Highly selective capture of Hg(II) utilizing a MXene-based magnetic cenosphere: Balance on redox sites and magnetism

Hg(II), as a hazardous water pollutant, is attracting increasing attention due to its severe ecological and biological toxicity. Herein, a magnetic composite MXene/Fe3O4/FAC for aqueous Hg(II) uptake was prepared. It appeared fast adsorption kinetics (∼30 min of adsorption equilibrium time), high Hg capacity (924.34 mg/g), broad working pH range (pH=4–12), and high selectivity. Besides, the implanted Fe3O4 empowered the composite with good recycling and reusing characteristics, effectively preventing the release of nanomaterials into the environment. Multiple adsorption models and characterizations revealed the Hg(II) adsorption behaviors and mechanisms and the impact of Fe3O4 on Hg(II) adsorption onto MXene. Specifically, Hg(II) reductive adsorption aroused by the low-valence Ti species (abbreviated as Ti*) is the foremost mode of MXene. With the increasing of Fe3O4 (especially trivalent Fe), Ti* tends to be oxidized and covered by Fe3O4, and less Ti* can be used for Hg(II) reductive adsorption, leading to slower adsorption kinetics and lower adsorption capacity. The introduced inert carrier FAC favors the good dispersion of Fe3O4 and MXene to alleviate the oxidation of MXene, achieving the high utilization of MXene materials. The new insight into the interaction between MXene and Fe3O4 can beneficially guide the synthesis of Hg(II) magnetic adsorbents and MXene-based functional materials.

Modulation of Selectivity and Activity of Ni/TiO2 Catalysts by Metal Dispersion in Photothermal CO2 Hydrogenation

Ni/TiO2 catalysts are efficient and cost‐effective for photothermal CO2 hydrogenation. However, the achieved CO/CH4 ratio strongly depends on the specific characteristics of these catalysts. To further ascertain the role of metal dispersion and photoactivation on selectivity, in this work we investigate the impact of Ni loading over high surface area anatase on the photothermal performance. Catalysts with 3 and 10 wt. % of Ni prepared by incipient wetness impregnation show initial good dispersion of the metal, although after activation in H2 metallic Ni nanoparticles are observed for 10%Ni/TiO2. This last catalyst demonstrates superior CO2 hydrogenation activity at high temperature, but below 200 ºC it is overpassed by the catalyst with 3 wt % Ni/TiO2. The selectivity varies remarkably with Ni loadings. Thus, at 350 °C about 93 % of methane is obtained over 10 wt.% Ni/TiO2, while 3%Ni/TiO2 yields about 97 % of CO. Low‐intensity UV irradiation enhances performance, particularly at temperatures below 200 ºC, where an increment in the production of methane of up to 75 % is observed for 3 wt.% Ni/TiO2 at 200 ºC. These results highlight the influence of metal dispersion, along with irradiation on modulating the selectivity of the photothermal CO2 hydrogenation

Effect of different precipitants on the formation of ultrafine 3 mol% yttrium-stabilized zirconia nanopowders by reverse precipitation

This study proposes a simple method for preparing highly dispersed ultrafine 3 mol% yttrium-stabilized zirconia nanopowders (3YSZ NPs), which provide high-quality powders for use in high-performance ceramics. First, 3YSZ NPs were prepared using a reverse precipitation method with different precipitants: NaOH, NH3·H2O and (NH3)2CO3. The thermal decomposition, phase evolution, morphology and chemical composition of the precursor particles and 3YSZ NPs were analysed. The effects of precipitant and reaction conditions on 3YSZ NPs were systematically studied. The results show that there are differences in the mechanism of powder synthesis using the co-precipitation method among the three precipitants. In addition, ultrafine 3YSZ NPs with minimum agglomeration and high sphericity can be prepared using NaOH. Y3+ and ZrO2+ cannot coprecipitate in solution according to the designed molar ratio in the NH3·H2O and (NH4)2CO3 methods. Considering agglomeration, crystallinity and elemental distribution, NaOH is the best precipitant. The prepared zirconia powder exhibits high crystallinity, good dispersion, a narrow particle size distribution and a tetragonal phase structure. By investigating the effects of calcination temperature, titration end point pH and NaOH concentration, 3YSZ NPs with an average particle size of 22.29–38.94 nm are obtained.

Effects of novel carbon sources additives on the solid-state sintering behavior and properties of SiC ceramics

To enhance the density of SiC and improve the purity of the SiC, carbon is frequently used as a sintering additive. SiC ceramics were prepared in this study by using various carbon sources (graphitic carbon microsphere, carbon black, and flake graphite) combined with B4C through spark plasma sintering (SPS) at temperatures ranging from 1800 °C to 1900 °C. Among the above carbon sources, the graphitic carbon microspheres were created by hydrothermal carbonization combined with catalytic graphitization. The influence of the carbon sources on the phase compositions, microstructure, physical properties, and oxidation resistance of the SiC specimens was investigated. The findings revealed that the SiC specimens prepared with graphitic carbon microsphere had a smaller crystallite size than those prepared with other kinds of carbon. The SiC specimens prepared with graphitic carbon microsphere displayed high relative density, hardness, fracture toughness, and remarkable oxidation resistance. This was attributed to the lower oxygen content, better dispersion, and higher chemical reactivity of graphitic carbon spheres. In terms of the oxidation resistance of SiC specimens, factors such as purity (residual carbon) and porosity were found to have a more significant impact than grain size. In general, the use of carbon sources with high reactivity and good dispersion is an effective method in preparing SiC ceramics.

Polyetherketoneketone/carbon fiber composites with an amorphous interface prepared by solution impregnation

Interfacial adhesion between carbon fibers (CF) and polyetherketoneketone (PEKK) is a key factor that affects the mechanical performances of their composites. It is therefore of great importance to impregnate the CF bundles with PEKK as efficiently as possible. We report that PEKK with a good dispersion in a mixed solution of 4-chlorophenol and 1,2-dichloroethane can be introduced onto CF surfaces by solution impregnation and curing at 280, 320, 340 and 360 °C. The excellent wettability or infiltration of the PEKK solution guarantees a full covering and its tight binding to CFs, making it possible to evaluate the interfacial shear strength (IFSS) with the microdroplet method. The interior of the CF bundles is completely and uniformly filled with PEKK by solution impregnation, leading to a high interlaminar shear strength (ILSS). The maximum IFSS and ILSS reached 107.8 and 99.3 MPa, respectively. Such superior shear properties are ascribed to the formation of amorphous PEKK in the small spaces between CFs.

A Green Synthesis of Au-Ag Alloy Nanoparticles using Polydopamine Chemistry: Evaluation of their Anticancer Potency Towards Both MCF-7 Cells and their Cancer Stem Cells Subgroup.

Limited chemotherapy efficacy and cancer stem cells (CSCs)-induced therapeutic resistance are major difficulties for tumour treatment. Adopting more efficient therapies to eliminate bulk-sensitive cancer cells and resistant CSCs is urgently needed. Based on the potential and functional complementarity of gold and silver nanoparticles (AuNPs or AgNPs) on tumour treatment, bimetallic NPs (alloy) have been synthesized to obtain improved or even newly emerging bioactivity from a combination effect. This study reported a facile, green and economical preparation of Au-Ag alloy NPs using biocompatible polydopamine (PDA) as a reductant, capping, stabilizing and hydrophilic agent. These alloy NPs were quasi-spherical with rough surfaces and recorded in diameters of 80 nm. In addition, these alloy NPs showed good water dispersity, stability and photothermal effect. Compared with monometallic counterparts, these alloy NPs demonstrated a dramatically enhanced cytotoxic/pro-apoptotic/necrotic effect towards bulk-sensitive MCF-7 and MDA-MB-231 cells. The underlying mechanism regarding the apoptotic action was associated with a mitochondria-mediated pathway, as evidenced by Au3+/Ag+ mediated Mitochondria damage, ROS generation, DNA fragmentation and upregulation of certain apoptotic-related genes (Bax, P53 and Caspase 3). Attractively, these Au-Ag alloy NPs showed a remarkably improved inhibitory effect on the mammosphere formation capacity of MCF-7 CSCs. All the positive results were attributed to incorporated properties from Au, Ag and PDA, the combination effect of chemotherapy and photothermal therapy and the nano-scaled structure of Au-Ag alloy NPs. In addition, the high biocompatibility of Au-Ag alloy NPs supported them as a good candidate in cancer therapy.

Synthesis of BiOBr/graphene oxide photocatalyst assisted by sodium dodecyl sulfate for efficient degradation of organic pollutants

Surfactant‐assisted synthesis of photocatalysts for water treatment has received extensive attention from researchers. In this paper, a novel and efficient BiOBr/graphene oxide (BiOBr/GO) photocatalyst assisted by sodium dodecyl sulfate (SDS) was synthesized by a simple solvothermal method. Compared with use of other surfactants, like polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), BiOBr/GO (SDS) shows outstanding photocatalytic degradation activity under optimal conditions: The degradation rate constants of BiOBr/GO (SDS) for oxytetracycline (OTC), tetracycline hydrochloride (TCH), brilliant blue (BB), and Rhodamine B (RhB) are 0.073, 0.057, 0.166, and 0.626 min−1, which are 2.8, 1.8, 9, and 1.5 times larger than pure BiOBr, respectively. In addition, after five cycles, BiOBr/GO (SDS) exhibits superior cycling stability. The enhanced photocatalytic performance can benefit from the introduction of SDS and GO. With the assistance of SDS in the preparation process, BiOBr/GO (SDS) nanosheets have good adsorption performance and dispersion effect, which is favorable for raising their specific surface area. Meanwhile, the electron capture effect of GO improves the transfer and separation efficiency of photogenerated carriers. Moreover, the possible degradation pathway for TCH is identified through liquid chromatography–mass spectrometry (LC–MS). This research can become a valuable reference for synthesizing photocatalysts with visible light response to degrading organic pollutants such as antibiotics and dyes.

Design of novel electrochemical sensor functionalized with green nanoparticles for tetracycline monitoring

AbstractIncreasing the release of antibiotics in particular tetracycline in the environment is become one of the most concerns that threat human and animals' health. Regarding their low cost, sensitivity, portability, electrochemical sensors have received attention for tetracycline monitoring. With a nanostructure, diverse active functional sites, and good conductivity, green nanoparticles are considered now as an attractive material for sensors design. The objective of the present paper is then the design of electrochemical sensor functionalized with green nanoparticles based on gum Arabic for tetracycline detection. The green nanoparticles are synthesized by direct reduction of silver nanoparticle with gum Arabic polymer. The intrinsic properties of the obtained nanoparticles are examined using different techniques namely UV–Vis absorption (UV), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric TGA. To follow up, the sensor modification as well as tetracycline detection, cyclic voltammetry (CV) and square wave voltammetry are carried out. Correlation between the different results have demonstrated good dispersion and homogeneity of green nanoparticles, with good applicability in electrochemical measurements. In fact, the sensor has demonstrated wide concentrations range from 0.1 to 1250 nM with a limit of detection in the order of 0.056 nM, lower than those reported in the literature. The selectivity test, investigated against a various interfering with similar structure to tetracycline, have proven a good discrimination between all molecules. In addition, the sensor was successfully applied to real samples, and the found recovery rates are ranging from 90.4% to 106.9%. The obtained results confirm that green nanoparticles based on gum Arabic could commercially be viable for next generation of electrochemical sensor for tetracycline detection, and also could be applied for the detection of the variety of pharmaceutical pollutants in the environment.

Addition of Coffee Waste-Derived Plasticizer Improves Processability and Barrier Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-Natural Rubber Bioplastic.

This study aimed to develop a value-added bio-based polymer product for food packaging. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a promising bioplastic with limitations in processability and brittleness, which our group previously addressed by incorporating high-molecular-weight natural rubber (NR) compatibilized with peroxide and coagent. Yet, processability in an industrial setting proved difficult. Coffee oil epoxide (COE), a waste-derived plasticizer, was incorporated into the PHBV/NR/peroxide/coagent matrix via extrusion, and properties of resulting sheets were evaluated. COE incorporation significantly decreased the oxygen and water permeability of the PHBV/NR sheets. Maximum degradation temperature Tpeak (°C) increased by ~4.6 °C, and degree of crystallinity decreased by ~15.5% relative to pristine PHBV, indicating good thermal stability. Melting (Tm) and glass transition temperatures (Tg) of the PHBV/NR blend remained unchanged with COE incorporation. X-ray diffraction (XRD) revealed ~10.36% decrease in crystal size for the plasticized blend. Energy-dispersive X-ray analysis (EDAX) and scanning electron microscopy (SEM) confirmed good dispersion with no phase separation. The water uptake capacity of the plasticized blend was reduced by 61.02%, while surface contact angle measurements showed improved water resistance. The plasticized PHBV sheet shows promise for environmentally friendly packaging films due to its high thermal stability, effective barrier properties, and industrial scalability.

A novel nanosheets assembled Co2P2O7 microrods for ultrasensitive electrochemical detection of As(III) ions

Arsenic pollution is common in seafood, grains, fruits, vegetables and groundwater. Long-term intake of arsenic-contaminated food or water may lead to various health problems. In this study, a novel nanosheets assembled Co2P2O7 microrod was prepared via a simple one-step hydrothermal method for the electrochemical detection of As(III). The Co2P2O7 microrods showed superior electric conductivity, good dispersion and a unique layered structure, which provided numerous electroactive sites to bind with As(III) and promoted the direct oxidization of As(III) to As(V) on the modified electrode surface. The proposed electrochemical sensor showed a high sensitivity of 4.174 µA/µg L−1 and a wide linear range of 0 ∼ 30 µg L−1 for As(III) detection via differential pulse voltammetry method in 0.1 M HAc-NaAc buffer (pH 5.0). Additionally, it exhibited good repeatability, reproducibility, stability and selectivity for As(III) detection. Moreover, the proposed sensor exhibited satisfactory applicability in hairtail samples.

Potato peel carbon dots produced via fixed bed pyrolysis reactor decorated 1-D TiO2 nanorods for rapid removal of methylene blue, Cr (VI), Escherichia coli, and Aspergillus niger

In this work, new type carbon quantum dots produced from waste of biomass were used as a dopant molecule in order to investigated photocatalytic properties of TiO2 nanorods structures. Low-cost and eco-friendly carbon quantum dots (CQDs) were obtained via slow pyrolysis of potato peels (PP) as a biomass waste without any chemicals by fixed bed pyrolysis. Potato peel quantum dots (P-CQDs) decorated TiO2 nanorods (P-CQDs/TNRs) were synthesized were by utilizing their high specific surface area, good dispersion, abundant surface functional groups. (P-CQDs) were imposed on the surface of the one-dimensional TiO2 nanorods fabricated via chemical impregnation method for P-CQDs/TiO2 nanorods (P-CQDs/TNRs) that TiO2 nanorods have been fabricated by hydrothermal route. Characteristic properties of as-prepared P-CQDs/TNRs photocatalysts were characterized employing TGA, XRD, XPS, FE-SEM/EDS, HRTEM, FTIR, fluorescence and UV–vis spectroscopy, resp. The photocatalytic activity of as-prepared P-CQDs/TNRs were investigated for methylene blue, hexavalent chromium, Escherichia coli and Aspergillus niger under UV-A. The obtained results suggest that the photocatalytic activity of P-CQDs/TNRs composites was slightly enhanced as compared to that of TNRs. The scenario behind the superior photocatalytic activity of P-CQDs/TNRs may be having a synergetic effect between P-CQDs molecules and the surface of TNRs, and also the design of the charge-transfer channel of TNRs. Moreover, the carbon derived from a natural green source possesses the various functional groups such as CC, C-OH, C-O-C, CO, and when these functional groups deposited to the surface of the TiO2 nanorods, newly formed nanocomposites can improve the visible light-driven photocatalytic activity.

Study on the preparation of green tea hand wash gel

Green tea exhibits beneficial effects on the skin, such as deodorization, antibacterial properties, sun protection, and antioxidant activity. Formulating hand wash from green tea leverages these advantages in personal hygiene products. This study was conducted to investigate the ratios of surfactants, thickeners, and moisturizers in the formulation of hand wash gel containing green tea. Nine different formulations with surfactant ratios ranging from 9-15%, thickener ratios 1-2%, and moisturizer ratios 5-9% were examined. Sensory characteristics, pH, dirt dispersion ability, viscosity, foam height, and foam stability were evaluated to select the most appropriate formulation. The results showed that the F8 formulation had suitable sensory characteristics, a pH of 5.53, good dirt dispersion ability, a viscosity of 152.6 Cps, a foam height of 5.1 cm, and foam stability of 94.12%. According to Organisation for Economic Co-operation and Development (OECD) guidelines, the product did not exhibit skin irritation in tests conducted on rabbits.Thus, the optimal formulation for green tea hand wash gel was determined to include 1% green tea extract (dry extract form), 12% surfactant, 1.5% thickener, 7% moisturizer, other additives, and water to make up to 100%.

Selective detection of Co2+ by L-CyS/AA CQDs and Construction of PASS 0 gate

Since the accidental discovery of carbon quantum dots (CQDs) in 2004, they have been widely used in the field of fluorescence sensing by combining their good optical and physicochemical properties with a wide source of raw materials and a simple synthesis process. In this work, we have synthesised sulphur-doped carbon quantum dots L-CyS/AA CQDs by a one-step microwave method using L-cysteine (L-CyS) and ascorbic acid (AA) as carbon and sulphur sources. It was also analysed by fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The prepared L-CyS/AA CQDs showed good dispersion under TEM with a spherical shape and an average particle size of 7.3 nm. L-CyS/AA CQDs were observed to be bright blue-green fluorescent with strong fluorescence (>3.5*103 a.u.) under UV light irradiation. PASS 0 logic gate operation can be achieved by controlling different fluorescent input and output. L-CyS/AA CQDs were able to achieve selective detection of Co2+ with a LOD of 63.2 μM, which provides a new method for Co2+ detection that can be used for the detection of Co2+ in real water samples.

Development of polymeric nanocomposites (Nylon 6/PVA with ZrO2/SiO2) by ultrasound-assisted melt-extrusion for adsorption of lead (II)

This is the first study of polymeric nanocomposites (Nylon 6/PVA with ZrO2/SiO2 nanoparticles) by ultrasound-assisted melt-extrusion for adsorption of lead (II). In XRD, upon adding the nanoparticles, a change in the crystalline structure of the polymer could be observed. The SEM images indicate a good dispersion of the nanoparticles with sizes of 30–38 nm. In the lead (II) adsorption tests, the removal of 80 % was achieved at pH 6 for the NyPVA/ZrO2-SiO2 6 % sample.

Synthesis, characterization and corrosive resistance of ZnO and ZrO2 coated TiO2 substrate prepared via polymeric method and microwave combustion

The TiO2 substrate coatings containing varied ZnO or ZrO2 nanoparticles were made using the polymeric and microwave combustion methods and then thermally treated at various temperatures. Furthermore, before coating on the substrate, the produced nanoparticles undergo characterization and calcination to optimize the conditions for developing ZnO and ZrO2 phases and track their composition. The X-ray diffraction method (XRD), transmission electron microscopy (TEM), and infrared analysis (IR) are used to characterize the calcined produced nanoparticles. After heat treatment at 1000 °C, the TiO2 substrate is prepared. The produced coated substrate is studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR), apparent porosity, bulk density, chemical corrosive properties and electrochemical measurement in 3.5 % NaCl and 1 M HCl solutions. The corrosion resistance of ZnO or ZrO2-covered TiO2 substrate is ascertained by anticorrosive behaviors, which include weight loss, apparent porosity, corrosion rate, and SEM. The findings showed that 800 °C is the ideal temperature for preparing ZrO2-coated substrate, whereas 1000 °C is the perfect temperature for preparing ZnO-coated substrate. The microstructure reveals surface micro-cracks on the ZrO2-coated TiO2 substrate. Good dispersion, homogeneity, and compaction were noted for the ZnO-coated substrate. Between 14 and 17 % of the ZnO-coated substrate and 20–21 % of the ZrO2-coated substrate, made via polymeric and microwave combustion techniques, had visible porosity when ZnO-coated samples exhibited greater corrosion resistance against NaCl media. In contrast, ZrO2-coated samples had much stronger anticorrosive qualities in HCl media than uncoated and Zn-coated samples. According to the electrochemical results, the ZnO-coated TiO2 synthesized by polymeric technique at 1000 °C showed 99.86 % inhibitory efficiency against NaCl. An inhibitory efficiency of 94.4 % was observed in a ZrO2-coated TiO2 substrate that was produced at 800 °C using a polymeric technique.

Highly dispersed Pd nanoparticles supported by magnetically separable Fe3O4@ SiO2 nanotube for catalytic hydrogenation of nitroaromatics

Selective hydrogenation of nitroaromatics is a crucial industrial reaction, but there are still challenges in developing nanocatalysts with stable active centers, yet easily recyclable characteristics. Here, a magnetically separable Pd/Fe3O4@SiO2 nanocatalyst was prepared through the seeding growth of silica on the Fe3O4 nanocrystal cluster (NC) followed by in situ reduction of Pd nanoparticles (NPs) on the amino group modified Fe3O4@SiO2 nannotube (NT). The nanocatalyst showed good activity and stability in the hydrogenation of a series of nitroaromatics as the Pd NPs were highly dispersed on the nanotubes. Meanwhile, it could be easily separated from the reaction solution and well-redispersed in the solvent for the next-round reaction due to the superparamagnetic property of the Fe3O4 NC and the good dispersibility of silica in many organic solvents. The magnetically separable nanocatalyst combined the high activity of the nanocatalyst and the convenient separation of a traditional heterogeneous catalyst, which effectively promote the practical application of nanomaterials in catalysis.

Stable loading of MOF-derived carbon skeleton encapsulated Ni and BiOBr on carbonized cellulose fibers for fabricating high-performance and recyclable photocatalytic paper

The highly dispersed small-size metal co-catalysts can effectively improve the photocatalytic efficiency of semiconductor photocatalysts by separating photogenerated electrons and enriching active sites. However, this system tends to aggregate in the absence of carrier, resulting in the decrease of active sites. Here, MOF-derived carbon skeleton (MDCS) encapsulated Ni nanoparticles (Ni@MDCS) and BiOBr was loaded onto carbonized cellulose fibers (CCF) with the help of polydopamine (PDA) to construct high-performance and recyclable photocatalytic paper for photocatalytic degradation of organic dyes in water. The characterization results showed that MDCS promoted good dispersion of Ni nanoparticles and provided sufficient active sites. And Ni@MDCS as a co-catalyst accelerated the separation of photogenerated carriers in BiOBr. The PDA improved the loading state of Ni@MDCS on CCF and converted into N-doped C in the carbonization process for further increasing the transfer efficiency of photogenerated electrons. In the composite paper, the stable loading of Ni@MDCS/BiOBr hybrid on CCF improved the dispersion and reusability of photocatalyst. The degradation rate of rhodamine B on CCF/PDA-C/Ni@MDCS/BiOBr paper was as high as 94.6 % after 60 min visible light irradiation, which was about 2.5 times higher than that of CCF/BiOBr paper. During 10 cycles, CCF/PDA-C/Ni@MDCS/BiOBr paper maintained high photocatalytic efficiency and good structural stability. This study provides a new way for developing high-performance and recyclable photocatalytic paper.