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1.
This study reports facile in situ synthesis of magnetically retrievable nanocomposites of nanocellulose (derived from waste biomass) and NiFe 2O 4 nanoparticles using hydrothermal method. The synthesized nanocomposites were characterized using various techniques such as FT-IR, powder XRD, HR-TEM, BET and VSM. The characterization of nanocomposites clearly revealed that NiFe 2O 4 nanoparticles were well dispersed on the surface of cellulose nanofibres. The catalytic performance of the synthesized nanocomposites was assessed for both the photocatalytic oxidation and reduction of organic pollutants. The prepared nanocomposites displayed excellent catalytic performance in comparison to pristine NiFe 2O 4 nanoparticles due to stabilization and increased dispersability of NiFe 2O 4 nanoparticles on the cellulose matrix. The present work promotes the use of bio based renewable sources to fabricate environment friendly materials to be used in the field of catalysis for the abatement of organic pollutants. 相似文献
2.
In this work, the NiFe 2O 4@TiO 2/reduced graphene oxide (RGO) ternary nanocomposites with high saturation magnetization and catalytic efficiency have been synthesized through the following steps. First, graphene oxide was prepared using the modified Hummer's method. Second, the NiFe 2O 4 nanoparticles were successfully prepared using the hydrothermal method. Third, the core shell‐structured NiFe 2O 4@TiO 2/RGO nanocomposite precursors were easily obtained through hydrolysis reaction. The morphology of NiFe 2O 4@TiO 2/RGO nanocomposites was characterized from scanning electron microscope (SEM) and transmission electron microscope (TEM) images. Moreover, the results of X‐ray diffraction (XRD) patterns proved that the TiO 2 coating shell consisted of anatase. The vibrating sample magnetometer (VSM) measurements showed that the saturation magnetization value of NiFe 2O 4@TiO 2/RGO ternary nanocomposites was 25 emu/g. The X‐ray photoelectron spectroscopy (XPS) analysis confirmed that only part of the graphite oxide (GO) was reduced to RGO in the ternary nanocomposite. The degradation experiments proved that NiFe 2O 4@TiO 2/RGO nanocomposite exhibited the high catalytic efficiency and outstanding recyclable performance for rhodamine B (RhB). 相似文献
3.
A magnetic photocatalyst TiO 2/NiFe 2O 4 (TN) with typical ferromagnetic hysteresis was prepared by a sol‐gel method, which is easy to be separated from a slurry‐type photoreactor under the application of an external magnetic field, being one of promising photocatalysts for wastewater treatment. The analysis of XRD indicated that the highly dispersed NiFe 2O 4 nanoparticles prevented the formation of rutile phase to some extent. A transmission electron microscope (TEM) was used to characterize the structure of the photocatalyst, indicating that the NiFe 2O 4 nanoparticles highly dispersed among TiO 2 nanoparticles. The prepared photocatalyst showed high photocatalytic activity for the degradation of methyl orange in water. The degradation results revealed that the NiFe 2O 4 nanoparticles played the role of recombination centre of photogenerated electrons and holes for the TN photocatalyst, which gave rise to the decrease in photocatalytic activity. Moreover, the experiment on recycled use of TN demonstrated a good repeatability of the photocatalytic activity. 相似文献
4.
在不同的表面活性剂和硫源的条件下,采用水热法制备了多种形貌的SnS 2纳米材料,详细讨论了反应条件对其形貌和性质的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、和BET比表面积法对制备的样品的物相、形貌和组成进行了表征,通过光催化降解罗丹明B研究了所得样品的光催化性能。结果表明:表面活性剂和硫源对产物的结构和形貌起到了重要的作用。当Sn 4+与表面活性剂的物质量的比为1:1时,样品均为纯的六方相SnS 2。采用柠檬酸三钠为表面活性剂、硫脲为硫源时制得的SnS 2纳米片具有最大的比表面积,同时表现出了最优的光催化性能。 相似文献
5.
Spinel structure nickel ferrite (NiFe 2O 4) doped graphitic carbon nitride (g-C 3N 4) photocatalyst NiFe 2O 4/g-C 3N 4 was synthesized by the coprecipitation route to enhance the photocatalytic activity for the visible-light driven degradation of methyl orange. The NiFe 2O 4 doping content is responsible for the microstructure and photocatalytic activity of NiFe 2O 4/g-C 3N 4 samples. Compared with pure NiFe 2O 4 and g-C 3N 4, the 2-NiFe 2O 4/g-C 3N 4 composite with NiFe 2O 4 doping of 2.0 wt% exhibited excellent photocatalytic activity and superior stability after five runs for degrading methyl orange under visible light irradiation. The catalytic activity of 2-NiFe 2O 4/g-C 3N 4 sample produced using the coprecipitation route was higher than those of conventional 2-NiFe 2O 4/g-C 3N 4 bulks prepared by the impregnation approach. The prepared samples for the photocatalytic degradation of methyl orange followed pseudo-first-order reaction kinetics. It’s ascribed to the synergistic effect between NiFe 2O 4 and g-C 3N 4, which can inhibit the recombination of photoexcited electron-hole pairs, accelerate photoproduced charges separation, and enhance the visible light absorption. 相似文献
6.
In this study, CoFe 2O 4/Sawdust and NiFe 2O 4/Sawdust magnetic nanocomposites were synthesized using a hydrothermal method, and then characterized using X-ray powder diffraction, Infrared, scanning electron microscopy, Brunauer–Emmett–Teller/Barrett–Joyner–Halenda, and vibrating-sample magnetometer techniques. In this study, unmodified sawdust (US), modified sawdust (MS), unmodified CoFe 2O 4/sawdust (UCS), modified CoFe 2O 4/sawdust (MCS), unmodified NiFe 2O 4/sawdust (UNS), and modified NiFe 2O 4/Sawdust (MNS) magnetic nanocomposites, which are inexpensive, economical, environmentally friendly absorbents, and have a high selective hydrophobic, were used for the removal of oil from the water surface. The results show that the UCS, MCS, UNS, and MNS magnetic nanocomposites can selectively absorb the oil spreading on the water surface, due to its superhydrophobicity and superoleophilicity, and can be easily collected from water under the influence of a magnetic field. In addition, the results showed that the absorbents reach their equilibrium at the 30-min mark. Among all the absorbents, the MNS magnetic nanocomposite showed the maximum absorption capacity (18.172 g/g) at the 40-min mark. The results of the kinetic studies showed that the second-order kinetic equation with the highest correlation coefficient had the best fit with the experimental results. 相似文献
7.
We used a simple two-stage tactic to design and synthesize a magnetically separable catalyst (MSC) Ag/Fe 3O 4 by combining independently synthesized Fe 3O 4 and Jatropha curcas root functionalized Ag nanoparticles (NPs) at room temperature. The phase composition of Ag/Fe 3O 4 NCs was revealed by morphological and structural assessment. The derived Ag/Fe 3O 4 nanocomposites demonstrated outstanding antimicrobial activity against Gram-negative Pseudomonas aeruginosa comparing to Gram-positive Bacillus subtilis which was determined by the agar well diffusion method. This is due to positively charged surface of metal oxide NPs that may bind to cell membrane. Interestingly, Ag–Fe 3O 4 NCs demonstrated good photocatalytic activity for organic dye degradation. According to a kinetic study, Ag/Fe 3O 4 MSC removed 99% of Rhodamine B at a rate constant of 1.89 min ?1. The photoelectron could perhaps ultimately collide only with dissolved solids in the substrate to form superoxides, which can damage the dye. Notably, the MSCs reusability was tested using magnetic detachment without sacrificing photocatalytic efficiency. This finding represents a significant breakthrough in the domain of wastewater treatment and biomedicine. 相似文献
8.
Three-dimensional Ag 2O and Ag co-modified flower-like SnS 2 composites have been synthesized through a facile hydrothermal and photoreduction process. The physical and chemical properties of Ag 2O and Ag co-modified flower-like SnS 2 composites were carefully studied by using XRD, SEM, TEM, UV–vis diffuse reflectance spectra (DRS) and XPS. The photocatalytic activity of the as-prepared products was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under solar light irradiation. The photocatalytic result shows that Ag 2O and Ag co-modified flower-like SnS 2 composites exhibit enhanced photocatalytic activity compared with that of pure SnS 2. Three of the Ag 2O and Ag co-modified flower-like SnS 2 composites form the Z-scheme systems, because of their unique charge-carrier transfer process, the oxidation/reduction ability of photogenerated holes and electrons could be enhanced. Therefore, the new Ag 2O and Ag co-modified flower-like SnS 2 composites possess a favorable photocatalytic activity, and it can be a promising candidate for the solar energy conversion process. 相似文献
9.
This present investigation focused on novel p-type bismuth ferrite (BiFeO3)/n-type tin sulfide (SnS2) heterostructure photocatalyst has been favorably attained via a facile two-step process followed by co-precipitation approach for enhances the photocatalytic activity through the degradation of Methylene Blue (MB) and Rhodamine B (RhB) organic dyes under visible-light illumination. Structural, optical, and photocatalytic behavior of the prepared BiFeO3 and BiFeO3/SnS2 photocatalysts are carefully explored. The photocatalytic efficiency of BiFeO3/SnS2 nanocatalyst was calculated to be 83%, 78% for MB and RhB, respectively, within 120 min illumination whereas the pure BiFeO3 nanoparticle was 58% and 56% for MB and RhB. This prominent enhancement of visible light photocatalytic activity can be ascribed to the separation as well as the transfer of photogenerated charge carriers, successful exploitation of visible light absorption and donates the enlarged number of photocatalytic active sites by the formation of BiFeO3/SnS2 p-n heterojunction. 相似文献
10.
Silver-titania nanocomposites (Ag-TiO 2 NCs) have unique functional attributes due to their photocatalytic and antibacterial properties. In this study, titania nanoparticles (TiO 2-NPs) were successfully in-situ decorated with silver nanoparticles (Ag-NPs) using the aqueous extract of goji berries (Lycium barbarum L .) as a bioreducing and stabilizing agent. Different Ag-TiO 2 NCs were synthesized by treating different concentrations of silver nitrate with a specific concentration of TiO 2-NPs in the presence of fruit extract. The green-synthesized NCs were characterized using several techniques viz., ultraviolet–visible spectrophotometry, X-ray diffractometry (XRD), scanning electron microscopy, field-emission transmission electron microscopy (FE-TEM), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. XRD analysis revealed the formation of face-centered cubic (fcc) crystals, and FE-TEM analysis revealed the embedment of Ag-NPs throughout the surface of TiO 2-NPs. The average size of Ag-NPs on TiO 2-NPs increased from 11.2 ± 3.05 nm to 16.4 ± 4.5 nm with an increase in the concentration of silver ions, and the morphology of Ag-NPs was predominantly quasi-spherical and hexagonal. These NCs exhibited an excellent photocatalytic degradation of an azo dye, methylene blue (MB). The synthesized Ag-TiO 2 NCs (3:1) showed higher photocatalytic degradation efficiency of ∼ 93.4% for MB in 130 min under visible light irradiation. Ag-TiO 2 NC S also exhibited good antibacterial activities towards Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Therefore, the formation of Ag-NPs on the surface of TiO 2-NPs to form Ag-TiO 2 NCs exhibits eco-friendly photocatalytic degradation of azo dye contaminants as well as antibacterial activity. 相似文献
11.
Advanced oxidation processes (AOPs) counting heterogeneous photocatalysis has confirmed as one of the preeminent method for waste water remediation. In the present work, we have successfully fabricated novel visible-light-driven nitrogen-doped graphene (NG) supported magnetic ZnO/ZnFe 2O 4 (ZnO/ZF/NG) and ZnO/CoFe 2O 4 (ZnO/CF/NG) nanocomposites. ZnO synthesized via direct precipitation method. Hydrothermal method was used for the preparation of nitrogen-doped graphene supported magnetic ZnO/ZF (ZnO/ZnFe 2O 4) and ZnO/CF (ZnO/CoFe 2O 4) nanocomposites. The procured materials were scrutinized by assorted characterizations to acquire information on their chemical composition, crystalline structure and photosensitive properties. The absorption and photocatalytic performance of photocatalysts were studied via UV–Visible spectra. Photodegradation performance of the synthesized nanocomposites was estimated toward mineralization of methyl orange (MO) and malachite green (MG) dyes in aqueous solution. The high surface area of ZnO/ZF/NG and ZnO/CF/NG was suitable for adsorptive removal of MO and MG dyes. The photodegradation performance of heterojunction photocatalysts was superior to bare photocatalyst in 140 min under visible-light irradiation. Spectrophotometer, GC–MS (Gas chromatography–mass spectrometry) elucidation was carried out to expose the possible intermediates formed. Both ZnO/ZF/NG and ZnO/CF/NG were rapidly isolated from the aqueous phase by applying an external magnetic field in 20 sec and 2 min, respectively. The photocatalytic performance and stability of ZnO/ZF/NG and ZnO/CF/NG nanocomposites were confirmed by conducting 10 consecutive regeneration cycles. Owing to recyclability of ZnO/ZF/NG and ZnO/CF/NG, these heterogeneous nanocomposites might be used as cost-effective for treatment of discarded water. The observations endorse that the synthesized ternary heterogeneous nanocomposites facilitates wastewater decontamination using photocatalytic technology. 相似文献
12.
Two different ternary nanocomposites, PPy/CNT/CoFe 2O 4 and PPy/CNT/NiFe 2O 4, were synthesized by in situ polymerization method. The resulting composites were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. They were evaluated with the aim of investigating microwave absorption properties. The results showed that the value of microwave reflection decreases as that of prepared nanocomposites increases. This happens with increase in the PPy content and polymerization on the surface. 相似文献
13.
In-situ synthesis of magnetic nanocomposites with (NiFe 2O 4/CuO/FeO) crystal phases has been done using a sol-gel method by taking a non-stoichiometric composition of the precursors. The average particle size of the nanocomposites was calculated using X-ray diffraction (XRD) and high resolution tunneling electron microscope (HR-TEM) and it turns out to be ∼20 nm. The vibrating sample magnetometer (VSM) measurements demonstrate the ferromagnetic nature of the nanocomposites. The synthesized nanocomposite was used to prepare magnetic fluid using tetramethylammonium hydroxide as a surfactant and its stability in the solution was also discussed. 相似文献
14.
通过液相催化相转化的方法制备了一种可磁分离的光催化剂TiO 2/SiO 2/NiFe 2O 4(TSN),这种光催化剂显示出了超顺磁性,能够通过外加磁场方便的实现催化剂在水中的分离与回收。该光催化剂的X-射线衍射和TEM结果表明:纳米TiO 2颗粒包裹在磁性颗粒-SiO 2/NiFe 2O 4(SN)的周围形成TiO 2层。利用光催化降解甲基橙的效果来考察了这种光催化剂的活性,结果表明:在NiFe 2O 4和TiO 2之间包覆一层无定型的SiO 2,可以显著的提高催化剂的脱色效果,3次循环后,仍能保持良好的催化活性。 相似文献
15.
Herein, for the first time, a direct Z‐scheme g‐C 3N 4/NiFe 2O 4 nanocomposite photocatalyst was prepared using facile one‐pot hydrothermal method and characterized using XRD, FT‐IR, DRS, PL, SEM, EDS, TEM, HRTEM, XPS, BET and VSM characterized techniques. The result reveals that the NiFe 2O 4 nanoparticles are loaded on the g‐C 3N 4 sheets successfully. The photocatalytic activities of the as‐prepared photocatalysts were evaluated for the degradation of methyl orange (MO) under visible light irradiation. It was shown that the photocatalytic activity of the g‐C 3N 4/NiFe 2O 4 nanocomposite is about 4.4 and 3 times higher than those of the pristine NiFe 2O 4 and g‐C 3N 4 respectively. The enhanced photocatalytic activity could be ascribed to the formation of g‐C 3N 4/NiFe 2O 4 direct Z‐scheme photocatalyst, which results in efficient space separation of photogenerated charge carriers. More importantly, the as‐prepared Z‐scheme photocatalyst can be recoverable easily from the solution by an external magnetic field and it shows almost the same activity for three consecutive cycles. Considering the simplicity of preparation method, this work will provide new insights into the design of high‐performance magnetic Z‐scheme photocatalysts for organic contaminate removal. 相似文献
16.
This study mainly focuses on the synthesis of two allotropes of graphene, graphene oxide (GO) and reduced graphene oxide (rGO), by the modified Hummers' method and chemical reduction method, respectively. Sm 2O 3/GO and Sm 2O 3/rGO nanocomposites were further synthesized in the presence of the cationic surfactant CTAB via the sol–gel method followed by the reflux method. Synthesized nanocomposites were subjected to characterization by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and UV–Visible spectroscopy to explore structural, thermal, optical, and photocatalytic properties. Characteristic FTIR peaks were observed in nanocomposites, and the bond length of the Sm-O bond was calculated. The Coats-Redfern method was employed to calculate the kinetics and thermodynamic parameters. Hexagonal crystallite shapes of Sm 2O 3/GO and Sm 2O 3/rGO nanocomposites with 11.8 and 13.13 nm crystallite sizes and 3.9 and 2.5 eV optical band gaps were observed. The photocatalytic efficiency of Sm 2O 3/GO and Sm 2O 3/rGO nanocomposites was assessed against the degradation of methylene blue in the presence of sunlight, and its degradation was confirmed through FTIR. The antimicrobial activities were also performed against the bacterial strains Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. 相似文献
17.
NiS (nickel sulfide)–In 2O 3 (indium oxide) nanostructures and NiS–In 2O 3 decorated on graphene oxide (GO) were demonstrated by ultrasonic/hydrothermal method. The structural study demonstrates the preparation of bixbyite and hexagonal phase of In 2O 3 and NiS for all of the synthesized catalysts. The band gap of the synthesized catalyst was determined to be in the range of 2.30–3.00 eV. A morphological evaluation by field emission scanning electron microscopy of NiS–In 2O 3 decorated on graphene oxide shows support for the NiS–In 2O 3 on the graphene oxide layer. Different test parameters were performed to study the phase and morphology. The particle sizes of the In 2O 3, NiS–In 2O 3 and NiS–In 2O 3/GO nanocomposites were 56.0, 62.0 and 66.0 nm, respectively. The photocatalytic performance of NiS–In 2O 3/GO nanocomposites was examined for the degradation of methylene blue dye under a UV lamp. The prepared sample shows 98.25% photocatalytic degradation within 40 min and at pH 9. With the presence the NiS and GO, the photo-degradation capacities of In 2O 3 and NiS–In 2O 3 are improved owing to the low band gap being calculated in UV–vis DRS analysis. The high ratio of NiS causes the highest photocatalytic properties of NiS–In 2O 3 nanocomposites owing to the enhancement of charge separation efficiency and generation of hydroxyl radicals. This study presents a facile and low-cost method to prepare highly active NiS–In 2O 3/GO nanocomposites. The antibacterial data indicate the significant properties of NiS–In 2O 3/GO nanocomposites for this study. 相似文献
18.
在不同的表面活性剂和硫源的条件下,采用水热法制备了多种形貌的SnS2纳米材料,详细讨论了反应条件对其形貌和性质的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、和BET比表面积法对制备的样品的物相、形貌和组成进行了表征,通过光催化降解罗丹明B研究了所得样品的光催化性能。结果表明:表面活性剂和硫源对产物的结构和形貌起到了重要的作用。当Sn4+与表面活性剂的物质量的比为1∶1时,样品均为纯的六方相SnS2。采用柠檬酸三钠为表面活性剂、硫脲为硫源时制得的SnS2纳米片具有最大的比表面积,同时表现出了最优的光催化性能。 相似文献
19.
Nanocrystalline tin (Sn) compounds such as SnO 2, SnS 2, SnS, and graphene nanocomposites were prepared using hydrothermal method. The X-ray diffraction (XRD) pattern of the prepared
nanocomposite reveals the presence of tetragonal SnO 2, hexagonal SnS 2, and orthorhombic SnS crystalline structure in the SnO 2/graphene nanosheets (GNS), SnS 2/GNS, and SnS/GNS nanocomposites, respectively. Raman spectroscopic studies of the nanocomposites confirm the existence of
graphene in the nanocomposites. The transmission electron microscopy (TEM) images of the nanocomposites revealed the formation
of homogeneous nanocrystalline SnO 2, SnS 2, and SnS particle. The weight ratio of graphene and Sn compound in the nanocomposite was estimated using thermogravimetric
(TG) analysis. The cyclic voltammetry experiment shows the irreversible formation of Li 2O and Li 2S, and reversible lithium-ion (Li-ion) storage in Sn and GNS. The charge–discharge profile of the nanocomposite electrodes
indicates the high capacity for the Li-ion storage, and the cycling study indicates the fast capacity fading due to the poor
electrical conductivity of the nanocomposite electrodes. Hence, the ratio of Sn compounds (SnO 2) and GNS have been altered. Among the examined SnO 2:GNS nanocomposites ratios (35:65, 50:50, and 80:20), the nanocomposite 50:50wt% shows high Li-ion storage capacity (400 mAh/g
after 25 cycles) and good cyclability. Thus, it is necessary to modify GNS and Sn compound composition in the nanocomposite
to achieve good cyclability. 相似文献
20.
Graphene-CdS (G-CdS) nanocomposites were successfully prepared by CdS nanocrystals (CdS NCs) formed in situ on the surface of graphene sheets, using graphene oxide (GO) sheets with rich negatively charged carboxylic acid groups as starting materials. Compared with pure CdS NCs, the presence of the graphene doped in G-CdS nanocomposites could facilitate the electrochemical redox process of CdS NCs; further, the as-prepared G-CdS nanocomposite can react with H 2O 2 to generate strong and stable electrochemiluminescent (ECL) emission, which not only enhances its ECL intensity by about 4.3-fold but also decreases its onset potential for about 320 mV. The as-prepared solid-state ECL H 2O 2 sensor shows acceptable linear response from 5 μM up to 1 mM with a detection limit of 1.7 μM (S/N = 3). The ECL H 2O 2 sensor exhibits excellent reproducibility and long-term stability. Such a property would promote the potential application of the graphene as enhanced materials in fabricating sensors for chemical and biochemical analysis. 相似文献
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