Catalyst For Reduction Of 4-nitrophenol Research Articles

Green synthesis of bimetallic Pd[sbnd]Ag alloy nanoparticles supported on polydopamine-functionalized kaolin for catalytic reduction of 4-nitrophenol and organic dyes

A green and universal synthesis strategy was demonstrated for preparation of bimetallic PdAg alloy nanoparticles supported on polydopamine-functionalized kaolin (kaolin-PDA-PdAg), where bimetallic PdAg alloy was synthesized by co-reduction of Na2PdCl4 and AgNO3 with sodium citrate. Characterization results, including TEM results and XPS results, confirmed that bimetallic PdAg was alloying state and kaolin-PDA-PdAg was successfully synthesized through mussel-inspired chemistry. The kaolin-PDA-PdAg nanocomposite exhibited excellent catalytic activity and performance towards reduction of 4-nitrophenol, whose rate constant was found to be 3.46 min−1 under condition of high concentration (10 mM) of 4-nitrophenol. Besides, kaolin-PDA-PdAg nanocomposite showed high catalytic performance for methyl orange and safranine-T as well. The high catalytic activity of kaolin-PDA-PdAg could be elucidated by electronic effect and synergistic effect of bimetallic PdAg alloy. These results suggest that kaolin-PDA-PdAg composites could be applied as high-efficiency catalysts for reduction of 4-nitrophenol and degradation of organic dyes. Furthermore, abundance and low-priced of raw materials kaolin, green and versatility of synthetic method endow kaolin-PDA-PdAg composites with broad application prospects. Strategy of bimetallic PdAg alloy anchored on kaolin in this text could provide an efficient platform for synthesis of bimetallic alloy nanoparticles loaded on various materials.

In-situ preparation of sulfonated carbonaceous copper oxide-zirconia nanocomposite as a novel and recyclable solid acid catalyst for reduction of 4-nitrophenol

The missing-linker defects of UiO-66 were exploited to covalently anchor Cu nanoclusters (Cu/UiO-66). The molecular interactions between the metals and oxides as copper-zirconia interfaces in Cu/UiO-66 are essential for heterogeneous catalysis, leading to remarkable synergistic impacts on activity and selectivity. Homogeneously distributed carbonaceous mixed metal oxides (CuO/ZrO2@C) nanocomposite was prepared via carbonization of the Cu/UiO-66 at 600 °C for 3 h in air. To enhance the acidity properties of the CuO/ZrO2@C nanocomposite, a small amount of sulfuric acid was added and heated at 150 °C under an N2 atmosphere (CuO/ZrO2-SO3H@C). The synthesised Cu/UiO-66 and CuO/ZrO2-SO3H@C catalysts were used as novel catalysts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The Cu/UiO-66 and CuO/ZrO2-SO3H@C catalysts displayed complete conversion of the 4-NP solution during (4 and 2 min) stirring at room temperature, respectively. These two catalysts exhibited a high reduction rate of 8.61 × 10–3 s−1, and 18.3 × 10–3 s−1, respectively. The X-ray photoelectron spectroscopic (XPS) analysis showed the charge of copper atoms in the Cu/UiO-66 catalyst was Cu0/CuII and in the CuO/ZrO2-SO3H@C catalyst was CuI/CuII with nearly the same ratio (65/35). The particle size and the elemental composition of the CuO/ZrO2-SO3H@C catalyst were analysed by using high resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy (EDS), and elemental mapping, respectively. The key point beyond the high catalytic activity and selectivity of the CuO/ZrO2-SO3H@C catalyst is both the carbon–metal oxides heterojunction structure that leads to good dispersion of the CuO and ZrO2 over the carbon sheets, and the high acidity properties that come from the combination between the Brønsted acid sites from sulfuric acid and Lewis acid sites from the UiO-66. The catalysts exhibited good recyclability efficiency without significant loss in activity, indicating their good potential for industrial applications.

Carboxymethyl cellulose/polyamidoamine hydrogel loaded with nano-Ag particles as recoverable efficient catalyst for reduction of 4-nitrophenol in water

Carboxymethyl cellulose/polyamidoamine hydrogel loaded with nano-Ag particles as recoverable efficient catalyst for reduction of 4-nitrophenol in water

Synthesis and Characterization of Fe3O4@SiO2@MgAl-LDH@Au.Pd as an Efficient and Magnetically Recyclable Catalyst for Reduction of 4-Nitrophenol and Suzuki Coupling Reactions

Synthesis and Characterization of Fe3O4@SiO2@MgAl-LDH@Au.Pd as an Efficient and Magnetically Recyclable Catalyst for Reduction of 4-Nitrophenol and Suzuki Coupling Reactions

Honeybee pollen assisted biosynthesis of nanogold and its application as catalyst in reduction of 4-nitrophenol

Nowadays, the exploration of natural materials for the production of nanoparticles is of special interest due to its ecofriendly nature. In this paper, we presented the biosynthesis of gold nanoparticles (AuNPs) in a green route by using water extract of pollen from Andean honeybees. Furthermore, AuNPs have been characterized by various techniques and tested for the catalytic reduction of 4-nitrophenol (4-NP). The biosynthesized AuNPs were analyzed using UV-vis spectroscopy, Transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectroscopy to confirm their optical properties, stability, surface morphology, and purity. The synthesized AuNPs proved to be well dispersed, spherical, and triangular in shape, with particle sizes ranging from 7 to 42 nm having λmax at 530 nm. Moreover, FTIR suggests the capping of AuNPs with pollen constituents and XRD confirms the crystalline structure of AuNPs. Additionally, prepared AuNPs were demonstrated to be effective in reducing organic pollutant 4-NP to 4-aminophenol (k = 59.17898 × 10−3 min−1, R2 = 0.994). All of these studies have emphasized that AuNPs production can be scale up by using naturally available pollen grains and open up a new perspective for beekeepers.

Selective Reduction of Aromatic Nitro Compounds to Amines From Pd Doped TiO2 Catalyzed Nano Catalyst

An efficient chemoselective reduction of aromatic nitro compounds to corresponding amino analogs was achieved using palladium doped TiO2 (Ti0.97Pd0.03O1.97) nanoparticles. The reductions are effectively carried out in the presence of aromatic nitro compounds of various other reducible functional groups such as halo, alkoxy, carbonyl, and cyanide. The reduction of aromatic nitro compounds to aromatic amines was recognized with excellent yield (100%) by using nano porous palladium as a sustainable catalyst and as a hydrogen source. Reduced amines were well characterized using PXRD, 1H NMR, and 13C NMR, spectroscopy. The stability and efficiency of the catalyst for reduction of 4-Nitrophenol were repeated for 9 cycles and the recovered catalyst was analyzed by XRD.

3-D porous cellulose nanofibril aerogels with a controllable copper nanoparticle loading as a highly efficient non-noble-metal catalyst for 4-nitrophenol reduction

Nitrophenols(NPs) are highly toxic compounds that occur in various industrial effluents. Herein, we investigated Cu nanoparticle-loaded cellulose nanofibril (CNF/PEI-Cu) aerogels as a catalyst for degrading 4-nitrophenol (4NP) in the wastewater. Non-noble metal based low-cost catalyst material and easily scalable preparation method make CNF/PEI-Cu aerogel as an appropriate catalyst for practical application in 4NP wastewater treatment. Our strategy to improve the loading amount of homogeneously distributed Cu nanoparticles was to functionalize a CNF aerogel using polyethylene imine (PEI), which can bind Cu2+ ions. Porous CNF aerogels with homogenously distributed 20–40 nm Cu nanoparticles were obtained by adsorbing Cu2+ ions and chemically reducing them to Cu metal. The FTIR, XRD, SEM, XPS and ICP-OES analysis were used to confirm the in-situ formation of Cu nanoparticles. In the presence of the CNF/PEI-Cu aerogels, 4NP was effectively reduced to 4-aminophenol (4AP) without loss of the Cu nanoparticles. The activation energy (Ea) and reaction rate constant (kapp) of the catalytic 4NP reduction reaction by the CNF/PEI2-Cu aerogels were calculated to be Ea = 39.56 kJ mol−1 and kapp = 0.770 min−1, respectively. The Ea is similar or even smaller than the Ea values of the corresponding reactions involving noble-metal catalysts, demonstrating that the CNF/PEI-Cu aerogels developed in the present study have strong potential as practical and economical catalysts.

One-pot synthesis of ultrathin 1T-MoS2 nanosheets as efficient catalyst for reduction of 4-nitrophenol

In present work, ultrathin 1T-MoS2 nanosheets were synthesized by a facile one-pot hydrothermal method through NH3 intercalation. The as-prepared 1T-MoS2 nanosheets showed an outstanding 4-nitrophenol (4-NP) reduction performance with apparent rate constant of 0.688 min−1 which was 2.6 times larger than that of 2H-MoS2 counterpart. This work opens up new opportunities for designing promising MoS2-based materials as superior 4-NP reduction catalysts.

3-D Porous Cellulose Nanofibril Aerogels with a Controllable Copper Nanoparticle Loading as a Highly Efficient Non-Noble-Metal Catalyst for 4-Nitrophenol Reduction

3-D Porous Cellulose Nanofibril Aerogels with a Controllable Copper Nanoparticle Loading as a Highly Efficient Non-Noble-Metal Catalyst for 4-Nitrophenol Reduction

Silver Particles Deposited Onto Magnetic Carbon Nanofibers as Highly Active Catalysts for 4-Nitrophenol Reduction

Silver Particles Deposited Onto Magnetic Carbon Nanofibers as Highly Active Catalysts for 4-Nitrophenol Reduction

3D N-doped graphene/bismuth composite as an efficient catalyst for reduction of 4-nitrophenol

In recent years, the development of low-cost and reusable green catalysts to reduce the organic pollutant of 4-nitrophenol (4-NP) into the utilizable intermediate of 4-aminophenol (4-AP) had attracted more and more attention. Herein, we reported a facile strategy to synthesize 3D N-doped graphene/bismuth (NGR/Bi) composites with efficient catalytic properties for 4-NP reduction. TGA exhibited NGR/8Bi catalyst came close to reach the maximum load of Bi (weight ratio 67%). NGR/8Bi catalyst had an apparent rate constant of 0.595 min−1. After 8 min of catalytic reaction, the conversion of 4-NP reached 99.15%. Doped N facilitated the uniform distribution of Bi on graphene and improved the specific surface area and porosity of the catalyst, all of which contributed to the improvement of catalytic performance. The good reusability was attributed to that the microstructure of catalyst had not been changed significantly after used. The 3D network similar to aerogel made NGR/8Bi very easy to recycle and reuse. EPR spectra showed that H* active free radical was responsible for the conversion of 4-NP. This work revealed that the total surface area of metal particles in metal catalyst composites could affect catalytic performance essentially due to the surface plasma resonance effect.

One-pot, green and surfactant-less synthesis of polyhedral PdNPs anchored on GO as superior catalyst for reduction of 4-nitrophenol

An aqueous-based, green, one-pot, and surfactant-less method to synthesize highly dispersed Pd nanoparticles (PdNPs) on graphene oxide (GO) nanosheets at room temperature was reported. The Pd/GO nanocomposites display an even distribution of highly-dispersed polyhedral PdNPs at high density onto GO sheets. The number density and size of deposited PdNPs are facilely adjusted by controlling the quantity of GO in the growth solution. The Pd/GO nanocomposites demonstrate a superior catalytic activity with apparent rate constant kapp of 1.057 min−1 and an excellent stability of up to 15 recycle times toward the reduction of 4-nitrophenol (4-NP) without any loss in efficiency. In addition, different factors including the amount of nanocatalysts, GO, ascorbic acid, and the molar ratio of 4-NP vs. NaBH4 also play crucial roles in manipulating the catalytic activities of the as-synthesized Pd/GO nanocomposites. This facile and green synthetic approach combined with their remarkable catalytic activity and durability highlight the potential of the Pd/GO nanocomposites in removal of recalcitrant organic compounds.

Three-dimensional Pyrenyl Graphdiyne Supported Pd Nanoparticle as an Efficient and Easily Recyclable Catalyst for Reduction of 4-Nitrophenol

Three-dimensional Pyrenyl Graphdiyne Supported Pd Nanoparticle as an Efficient and Easily Recyclable Catalyst for Reduction of 4-Nitrophenol

N-functionalized mesoporous carbon supported Pd nanoparticles as highly active nanocatalyst for Suzuki-Miyaura reaction, reduction of 4-nitrophenol and hydrodechlorination of chlorobenzene

A series of nanocatalysts derived from immobilization of palladium nanoparticles (Pd NPs) into three dimensional (3D) tube-type architecture of nitrogen (N) functionalized and without functionalized mesoporous carbon CMK-9 is developed by dual agents chemical reduction approach. Herein, for the first time N-functionalized CMK-9 is explored as supports to immobilize Pd NPs and use as multifunctional catalysts for Suzuki-Miyaura cross-coupling reaction, reduction of 4-nitrophenol and hydrodechlorination of chlorobenzene. The Pd@N-CMK-9 catalysts show excellent activities with 100% conversion for Suzuki-Miyaura reaction between iodobenzene and phenylboronic acid and turnover frequency up to 1992 h−1. When use as catalyst for reduction of 4-nitrophenol to 4-aminophenol, it delivers an outstanding rate constant of 4.22 × 10-2 s−1 with activity parameter of 51719 s-1g−1 with respect to only Pd content. The nanocatalysts also demonstrate 100% conversion of chlorobenzene to benzene within 1 h. In addition, the catalyst exhibits remarkable catalytic stability for several cycles without any significant loss of products. The excellent catalytic activities can be attributed to synergistic effect of uniformly dispersed Pd NPs, favorable interaction between metal and support, and tubular interconnected mesoporous framework of N-functionalized CMK-9 that accelerate mass transportation. The present work signifies the versatility of Pd@N-CMK-9 nanocatalysts for various catalytic reactions.

Maghemite/ZnO nanocomposites: A highly efficient, reusable and non-noble metal catalyst for reduction of 4-nitrophenol

Maghemite/ZnO nanocomposites synthesized by a two step process were used for catalytic reduction of p-nitrophenol. Maghemite nanoparticles were synthesized by hydrothermal technique followed by deposition of ZnO on it via co-precipitation process. X-ray diffraction analysis suggested formation of Maghemite and ZnO with tetragonal and hexagonal close packed structure respectively whereas electron microscopy images indicated the formation of near spherical nanocomposites with a size range of 30–50 nm. Maghemite/ZnO calcined at 300 °C is investigated as heterogeneous catalyst for reduction of p-nitrophenol and its catalytic activity is compared with that of Maghemite and ZnO nanoparticles. The parameters responsible for reduction of p-nitrophenol over Maghemite/ZnO were scrutinized using Response Surface Methodologyand the predicted values of reduction efficiency were found to be in a good agreement with the experimental findings (R2 > 0.9). The highest achievable percentage of reduction of target molecular species was noted to be of 98.6%. Optimization study showed that maximum reduction efficiency was observed at optimum conditions: p-NP concentration = 0.2 mM, Maghemite/ZnO loading = 200 ppm, reaction time = 6 min. Maghemite/ZnO has shown noticeably higher catalytic activity than pure oxides which remained almost unaltered for five consecutive cycling suggesting possible commercial potential of the developed material.

Solvent-free synthesis of N-doped carbon-based catalyst for high-efficient reduction of 4-nitrophenol

In this work, we report a facile, solvent-free, and one-step route for the fabrication of N-doped carbon by employing low-cost raw materials (i.e., alginic acid and ammonium chloride), which can serve as a high-efficiency metal-free catalyst for the reduction of 4-nitrophenol (4-NP). The as-prepared catalyst possesses high nitrogen content (up to 5.49 at%), high specific surface area (up to 630 m2g−1), and abundant defects, making it possible to provide sufficient active sites for the reduction of 4-NP. The excellent catalytic performance with high apparent rate constant (0.2141 min−1) and TOF value (1.33 ×10−4 mmolmg−1min−1), matches or even exceeds that of most reported metal-based catalysts. Density functional theory (DFT) calculations reveal that this excellent catalytic activity can be achieved via tuning the electron transfer and promoting the adsorption of 4-NP ions by introducing N atoms. The kinetic and thermodynamic parameters of the reaction were explored in detail, fitting well to the Langmuir-Hinshelwood model. This work not only proposes a versatile strategy to prepare advanced N-doped carbon materials but also provides useful guidance for designing and developing biomass-derived metal-free catalysts for various catalytic reactions.

Catalytic reduction of 4-nitrophenol to 4-aminophenol using an efficient Pd nanoparticles

Highly stable catalytically active polyvinyl alcohol supported Pd nanoparticles (Pd NPs) are synthesized and used as catalysts in reduction of 4-nitrophenol in aqueous phase by sodium borohydride as reducing agent. The as—synthesized Pd NPs are characterized with the help of UV—vis. absorption spectroscopy, X—ray diffraction (XRD), transmission electron microscopy (TEM). The TEM and high resolution TEM images reveal that the synthesized Pd NPs are mostly global shaped with mean radius of c.a. 2.1 nm. The progress of the reaction is conveniently monitored by UV—vis. spectroscopy. The rate constant of the pseudo—first—order reaction increases with temperature up to 318 K. The rate constant and the activation energy for the reduction of 4-nitrophenol by using Pd nanoparticles were found as 0.013 s−1 and 14.12 kJ mol−1 respectively at 318 K. The as-prepared Pd NPs are stable, easy to prepare, cost effective and have significant efficiency for reduction of 4—nitrophenol in green protocol.

A simple coordination complex-derived NiS nanocatalyst for reduction of 4-nitrophenol and methyl orange

A novel NiS nanocatalyst is synthesized by using simple coordination complex as precursors through an economic and straightforward sulfidation method, resulting in a high-performance catalyst for reduction of 4-nitrophenol (4-NP). The NiS nanocatalyst possess dispersed catalytic nanoparticles, high porosity and good electroactivity, leading to provide facile pathways for electron transfer. The as-prepared NiS nannocatalyst exhibits unusual catalytic activity according to fast apparent rate constant (kapp) of 1.413 min−1 and turn over frequency (TOF) of 2.5 × 10−3 mol·g−1·min−1. As expected, these structural features bring good catalytic properties to methyl orange (MO) reduction. It is expected this work will presents a practical experiment for using simple coordination complex as sacrificial templates to synthesize nanoparticles for wide applications.

Room-Temperature Polyol Synthesis of Ag/SiO2 Nanocomposite as a Catalyst for 4-Nitrophenol Reduction

We prepared silver nanoparticles (AgNP) embedded in SiO2 using a green polyol approach by conducting the synthesis at ambient temperature and pH. Glycerol solutions of SiO2 and silver nitrate were stirred overnight at room temperature. UV-vis spectra and TEM images of the reaction dispersion and XRD patterns of the centrifuged solid confirmed formation of AgNP (6 ± 2 nm) were embedded in SiO2. AAS showed that, about 50% of initial silver was deposited on SiO2. The presence of SiO2 enhanced the formation of AgNP and the stability of Ag/SiO2 in glycerol. The reason for these findings was probably the ultrasonic-probe dispersion of SiO2 in glycerol, which caused chemical interactions between glycerol and SiO2. Compared to bare AgNP, the AgNP/SiO2 demonstrated higher catalytic activity toward 4-nitrophenol reduction by NaBH4. The highest apparent rate constant was approximately 1.1 ∗ 10−4 s−1, comparable with Ag/SiO2 catalysts prepared using other methods. This study proposes a greener polyol method to synthesize SiO2-supported AgNP catalyst that does not require heating or regulating pH of the reaction mixture. This nanocomposite can be used in catalytic, antimicrobial, sensing, and other applications that are using AgNP/SiO2 synthesized by conventional methods.

One-step fabrication of Fe3O4–Cu nanocomposites: High-efficiency and low-cost catalysts for reduction of 4-nitrophenol

Transition metal Cu nanocrystals have shown promising prospects for degrading organic pollutants. Herein, high-efficiency Fe3O4–Cu nanocomposites (NCs) have been successfully synthesized though a facile one-step thermal decomposition method. With a turnover frequency of 6.4 min−1, our Fe3O4–Cu NCs (heated temperature: 225 °C) could degrade the 4-nitrophenol in less than 15 s and showed almost unchanged catalytic efficiency (>90%) after recycled reactions up to six times. Furthermore, the influence of the heat treatment on the structure, elemental distribution, magnetic property and catalytic performance of Fe3O4–Cu NCs was investigated. As the temperature increased from 225 °C to 285 °C, the saturation magnetization of Fe3O4–Cu NCs decreased from 7.27 to 26.2 emu/g, owing to the enlarged mass ratio of Fe3O4 nanocrystals: Cu nanocrystals. This work provides the practical design guidance to the large-scale fabrication of high-efficiency and low-cost Fe3O4–Cu NCs catalysts, which shows promising future for degrading the nitro compounds in wastewater.