Green synthesis of Pd@graphene nanocomposite: Catalyst for the selective oxidation of alcohols

Al-Marri, Abdulhadi H.; Khan, Merajuddin; Shaik, Mohammed Rafi; Mohri, Nils; Adil, Syed Farooq; Kuniyil, Mufsir; Alkhathlan, Hamad Z.; Al–Warthan, Abdulrahman; Tremel, Wolfgang; Tahir, Muhammad Nawaz

doi:10.1016/j.arabjc.2015.12.007

Cited by 57 publications

(36 citation statements)

References 48 publications

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“…To date, PEs have been used for the preparation of different metallic NPs and also for the reduction of GRO, however, they are rarely applied for the in-situ preparation of graphene-metallic NP-based nanocomposites [37][38][39]. For instance, in our previous study, Pd@graphene nanocomposites were prepared in a facile method by the simultaneous reduction of GRO and PdCl 2 using Salvadora persica L. (miswak) root extract (RE) as bioreductant [38]. The as-prepared nanocomposites demonstrated excellent catalytic activities towards the selective oxidation of alcohols.…”

Section: Introductionmentioning

confidence: 99%

Plant Extract Mediated Eco-Friendly Synthesis of Pd@Graphene Nanocatalyst: An Efficient and Reusable Catalyst for the Suzuki-Miyaura Coupling

et al. 2017

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Suzuki-Miyaura coupling reaction catalyzed by the palladium (Pd)-based nanomaterials is one of the most versatile methods for the preparation of biaryls. However, use of organic solvents as reaction medium causes a big threat to environment due to the generation of toxic byproducts as waste during the work up of these reactions. Therefore, the use of water as reaction media has attracted tremendous attention due to its environmental, economic, and safety benefits. In this study, we report on the synthesis of green Pd@graphene nanocatalyst based on an in situ functionalization approach which exhibited excellent catalytic activity towards the Suzuki-Miyaura cross-coupling reactions of phenyl halides with phenyl boronic acids under facile conditions in water. The green and environmentally friendly synthesis of Pd@graphene nanocatalyst (PG-HRG-Pd) is carried out by simultaneous reduction of graphene oxide (GRO) and PdCl 2 using Pulicaria glutinosa extract (PGE) as reducing and stabilizing agent. The phytomolecules present in the plant extract (PE) not only facilitated the reduction of PdCl 2 , but also helped to stabilize the surface of PG-HRG-Pd nanocatalyst, which significantly enhanced the dispersibility of nanocatalyst in water. The identification of PG-HRG-Pd was established by various spectroscopic and microscopic techniques, including, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. The as-prepared PG-HRG-Pd nanocatalyst demonstrated excellent catalytic activity towards the Suzuki-Miyaura cross coupling reactions under aqueous, ligand free, and aerobic conditions. Apart from this the reusability of the catalyst was also evaluated and the catalyst yielded excellent results upon reuse for several times with marginal loss of its catalytic performance. Therefore, the method developed for the green synthesis of PG-HRG-Pd nanocatalyst and the eco-friendly protocol used for the Suzuki coupling offers a mild and effective substitute to the existing protocols and may significantly contribute to the endeavors of green chemistry.

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Section: Introductionmentioning

confidence: 99%

Plant Extract Mediated Eco-Friendly Synthesis of Pd@Graphene Nanocatalyst: An Efficient and Reusable Catalyst for the Suzuki-Miyaura Coupling

et al. 2017

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“…Moreover, the band at 1650 cm −1 is characteristic of the C=O stretching vibration of the amide I band and the bandat 1570 cm -1 corresponds to the amide II band [42]. On the other hand, the NanoC presents not only the typical bands of the polymer but also bands at 1750 cm −1 and 1630 cm -1 that can be assigned to the functional group (>C=O) present in GO [43] assuring the presence of GO inside the hydrogel ( Figure 1a).…”

Section: Discussionmentioning

confidence: 99%

Hydrogel-Graphene Oxide Nanocomposites as Electrochemical Platform to Simultaneously Determine Dopamine in Presence of Ascorbic Acid Using an Unmodified Glassy Carbon Electrode

et al. 2018

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The detection of dopamine, an important neurotransmitter in the central nervous system, is relevant because low levels of dopamine can cause brain disorders. Here, a novel electrochemical platform made of a hydrogel–graphene oxide nanocomposite was employed to electrochemically determine simultaneously dopamine (DA) and ascorbic acid (AA). Unlike previous work, where the base electrode is modified, the active material (graphene oxide, GO) was dispersed in the hydrogel matrix, making an active nanocomposite where the electrochemical detection occurs. The GO, hydrogel and nanocomposite synthesis is described. Dynamic Light Scattering, UV-visible and FTIR spectroscopies showed that the synthesized GO nanoparticles present 480 nm of diagonal size and a few sheets in height. Moreover, the polymer swelling, the adsorption capacity and the release kinetic of DA and AA were evaluated. The nanocomposite showed lower swelling capacity, higher DA partition coefficient and faster DA release rate than in the hydrogel. The electrochemical measurement proved that both materials can be employed to determine DA and AA. Additionally, the nanocomposite platform allowed the simultaneous determination of both molecules showing two well separated anodic peaks. This result demonstrates the importance of the incorporation of the nanomaterial inside of the hydrogel and proves that the nanocomposite can be used as a platform in an electrochemical device to determinate DA using an unmodified glassy carbon electrode.

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“…For GO spectra, the G and the D-bands were shifted and appear at 1605 and 1346 cm −1 , respectively, due to the destruction of the sp 2 character by the oxidation process and presence of oxygenated functionalities [90]. While, for the spectrum of ZnO x (1%)-MnCO 3 /(1%)HRG, the G characteristic band is shifted by~11 cm −1 from 1605 to 1594 cm −1 , whereas a slight shift is noticed in the D-band from 1346 to 1342 cm −1 , which is an important evidence of the effective reduction of graphene oxide to highly reduced graphene oxide [52].…”

Section: Scanning Electron Microscopy (Sem) and Elemental Analysis (Edx)mentioning

confidence: 93%

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

et al. 2017

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Nanocomposites of highly reduced graphene oxide (HRG) and ZnO x nanoparticles doped manganese carbonate containing different percentages of HRG were prepared via a facile co-precipitation method.The prepared sample calcined at 300 • C yielded i.e., ZnO x (1%)-MnCO 3 /(X%)HRG (where X = 0-7), calcination at 400 • C and 500 • C, yielded different manganese oxides i.e., ZnO x (1%)-MnO 2 /(X%)HRG and ZnO x (1%)-Mn 2 O 3 /(X%)HRG respectively. The prepared catalyst were subjected to catalytic evaluation and a comparative catalytic study between carbonates and oxides for the liquid-phase aerobic oxidation of benzylic alcohols to corresponding aldehydes using molecular oxygen as an eco-friendly oxidant without adding additives or bases. The influence of various parameters such as percentage of HRG, reaction time, catalyst amount, calcination and reaction temperature was systematically examined to optimize reaction conditions using oxidation of benzyl alcohol as a substrate model. It was found that the catalytic performance is remarkably enhanced after using HRG as catalyst co-dopant for the aerobic oxidation of alcohols, possibly owing to the presence of carbon defects and oxygenated functional groups on HRG surface. The as-synthesized catalysts were characterized by SEM, EDX, XRD, Raman, TGA, BET, and FT-IR. Under optimal conditions, the catalyst with composition ZnO x (1%)-MnCO 3 /(1%)HRG calcined at 300 • C exhibited remarkable specific activity (57.1 mmol·g −1 ·h −1 ) with 100% conversion of benzyl alcohol and more than 99% product selectivity within extremely short time (7 min). The as-prepared catalyst was re-used up to five consecutive times without significant decrease in its activity and selectivity. To the best of our knowledge, the achieved specific activity is the highest so far compared to the earlier reported catalysts used for the benzyl alcohol oxidation. A wide range of substituted benzylic and aliphatic alcohols were selectively oxidized into their corresponding aldehydes with complete convertibility and selectivity in short reaction times without over-oxidation to the acids. Due to their significant low cost, superior reproducibility, excellent catalytic efficiency, the ZnO x (1%)-MnCO 3 /(X%)HRG nanocomposites possess several application prospect in other organic chemistry reactions.

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Green synthesis of Pd@graphene nanocomposite: Catalyst for the selective oxidation of alcohols

Cited by 57 publications

References 48 publications

Plant Extract Mediated Eco-Friendly Synthesis of Pd@Graphene Nanocatalyst: An Efficient and Reusable Catalyst for the Suzuki-Miyaura Coupling

Plant Extract Mediated Eco-Friendly Synthesis of Pd@Graphene Nanocatalyst: An Efficient and Reusable Catalyst for the Suzuki-Miyaura Coupling

Hydrogel-Graphene Oxide Nanocomposites as Electrochemical Platform to Simultaneously Determine Dopamine in Presence of Ascorbic Acid Using an Unmodified Glassy Carbon Electrode

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

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