Highly dispersed platinum nanoparticles supported on silica as catalyst for hydrogen production

Khdary, Nezar H.; Ghanem, Mohamed A.

doi:10.1039/c4ra09341k

Cited by 19 publications

(11 citation statements)

References 42 publications

(41 reference statements)

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“…It is worthy to note that bare silica shows ~1% C, ~0.5% H, and ~0.07% N contents, where it is believed that the organic contamination associated with the sample handling during the measurements likely resulted in detection of carbon, hydrogen, and very limited nitrogen content. Similar organic contents of bare silica were reported elsewhere [37,38].…”

Section: Resultssupporting

confidence: 88%

Recovery of Polyphenols from Grape Pomace Using Polyethylene Glycol (PEG)-Grafted Silica Particles and PEG-Assisted Cosolvent Elution

2019

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Adsorption on a functionalized surface can be an effective way of purifying polyphenols from complex plant extracts. Polymeric resins that rely on hydrophobic interactions suffer from low selectivity, weak affinity towards polyphenols, and lack tunability therefore making the purification of polyphenols less efficient. In this study, a purification process for the recovery of polyphenols from grape pomace extract was successfully developed using hydrogen bonding affinity ligands grafted on silica particles and PEG-assisted elution solvents. Bare silica (SiO2) and polyethylene glycol (mPEG)-grafted silica microparticles with molecular weights of 2000 and 5000 were tested to determine their polyphenol binding and release characteristics. Functionalizing the surface of bare silica with mPEG ligands increased the adsorption capacity by 7.1- and 11.4-fold for mPEG-2000 and mPEG-5000 compared to bare silica particles, respectively. This was likely due to the introduction of more polyphenol binding sites with mPEG functionalization. Altering the molecular weight (MW) of mPEG grafted on silica surfaces provided tunability in the adsorption capacity. A complete recovery of polyphenols (~99.9%) from mPEG-grafted silica particles was achieved by utilizing PEG–ethanol or PEG–water cosolvent systems. Recovered polyphenols showed up to ~12-fold antioxidant activity compared to grape pomace extract. This study demonstrates that mPEG-grafted silica particles and elution of polyphenols with PEG cosolvents can potentially be used for large-scale purification of polyphenols from complex plant extracts and simplify the use of polyphenols, as PEG facilitates remarkable solvation and is an ideal medium for the final formulation of polyphenols.

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Section: Resultssupporting

confidence: 88%

Recovery of Polyphenols from Grape Pomace Using Polyethylene Glycol (PEG)-Grafted Silica Particles and PEG-Assisted Cosolvent Elution

2019

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“…The formation of dithiocarbamate layers on SPIONs is confirmed by the presence of C–S and CS bonds at 660 and 1050–1200 cm –1 , respectively (spectrum 3, Figure B). Since these two bands are strongly overlapped with characteristic bands of Fe–O and Si–O–Si, the formation of dithiocarbamate moieties are further substantiated regarding compositions by elemental analysis [Table S1, Supporting Information (SI)] . The analysis of CHNS elements demonstrates an increase in sulfur content after modification with dithiocarbamate as compared to bare SPIONs and APTES-functionalized SPIONs.…”

Section: Resultsmentioning

confidence: 83%

High Antimicrobial Activity and Low Human Cell Cytotoxicity of Core–Shell Magnetic Nanoparticles Functionalized with an Antimicrobial Peptide

Maleki

Rai

Pinto

et al. 2016

ACS Appl. Mater. Interfaces

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Superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with antimicrobial agents are promising infection-targeted therapeutic platforms when coupled with external magnetic stimuli. These antimicrobial nanoparticles (NPs) may offer advantages in fighting intracellular pathogens as well as biomaterial-associated infections. This requires the development of NPs with high antimicrobial activity without interfering with the biology of mammalian cells. Here, we report the preparation of biocompatible antimicrobial SPION@gold core-shell NPs based on covalent immobilization of the antimicrobial peptide (AMP) cecropin melittin (CM) (the conjugate is named AMP-NP). The minimal inhibitory concentration (MIC) of the AMP-NP for Escherichia coli was 0.4 μg/mL, 10-times lower than the MIC of soluble CM. The antimicrobial activity of CM depends on the length of the spacer between the CM and the NP. AMP-NPs are taken up by endothelial (between 60 and 170 pg of NPs per cell) and macrophage (between 18 and 36 pg of NPs per cell) cells and accumulate preferentially in endolysosomes. These NPs have no significant cytotoxic and pro-inflammatory activities for concentrations up to 200 μg/mL (at least 100 times higher than the MIC of soluble CM). Our results in membrane models suggest that the selectivity of AMP-NPs for bacteria and not eukaryotic membranes is due to their membrane compositions. The AMP-NPs developed here open new opportunities for infection-site targeting.

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“…The surface of silica gel was functionalized by 3-aminopropyltriethoxysilane (APTS), according to the procedure reported in the literature. 39 FT-IR spectra were recorded using a Bruker FT-IR spectrophotometer as KBr disks. UV−vis spectra of solutions were recorded using a thermospectronic Helios Alpha spectrophotometer.…”

Section: ■ Conclusionmentioning

confidence: 99%

“…Solvents of the highest-grade commercially available (Merck) were used without further purification. The surface of silica gel was functionalized by 3-aminopropyltriethoxysilane (APTS), according to the procedure reported in the literature . FT-IR spectra were recorded using a Bruker FT-IR spectrophotometer as KBr disks.…”

Section: Experimental Sectionmentioning

confidence: 99%

Cu(II)-Hydrazide Coordination Compound Supported on Silica Gel as an Efficient and Recyclable Heterogeneous Catalyst for Green Click Synthesis of β-Hydroxy-1,2,3-triazoles in Water

et al. 2020

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A hydrazone ligand, (E)-6-(2-((2-hydroxynaphthalen-1-yl)methylene)hydrazinyl)nicotinohydrazide (H2L), was synthesized and characterized by spectroscopic methods. The reaction of H2L with CuCl2·2H2O in methanol gave Cu(II) coordination compound, [Cu(HL′)(Cl)]·CH3OH (1), which was characterized by elemental analysis and spectroscopic methods (Fourier transform infrared (FT-IR) and UV–vis). The structure of 1 was also determined by single-crystal X-ray analysis. Structural studies confirmed the formation of esteric group during the synthesis of 1. Compound 1 was immobilized on 3-aminopropyltriethoxysilane (APTS)-functionalized silica gel through the amidification reaction and the obtained heterogeneous coordination compound was utilized as a catalyst for the three-component azide–epoxide–alkyne cycloaddition reaction in water as a green solvent. The structural properties of the heterogeneous catalyst were characterized by a combination of FT-IR, UV–vis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS) analyses. The effect of the amount of catalyst and temperature on the cycloaddition reaction was studied, and the obtained 1,2,3-triazoles were characterized by spectroscopic studies and single-crystal X-ray analysis. The catalytic investigations revealed that this catalytic system has high activity in the synthesis of β-hydroxy-1,2,3-triazoles. It was also found that the aromatic and aliphatic substituents on the alkyne and epoxide together with the reaction temperature have considerable effects on the activity and regioselectivity of this catalytic system.

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Highly dispersed platinum nanoparticles supported on silica as catalyst for hydrogen production

Abstract: A synthetic approach is developed to produce highly disperse, low loading (3.28 wt%) Pt nanoparticles incorporated silica (Pt-NP–S) with average diameter of 3.5 nm using economical and simple surface chemical modification and reduction processes.

Cited by 19 publications

References 42 publications

Recovery of Polyphenols from Grape Pomace Using Polyethylene Glycol (PEG)-Grafted Silica Particles and PEG-Assisted Cosolvent Elution

Recovery of Polyphenols from Grape Pomace Using Polyethylene Glycol (PEG)-Grafted Silica Particles and PEG-Assisted Cosolvent Elution

High Antimicrobial Activity and Low Human Cell Cytotoxicity of Core–Shell Magnetic Nanoparticles Functionalized with an Antimicrobial Peptide

Cu(II)-Hydrazide Coordination Compound Supported on Silica Gel as an Efficient and Recyclable Heterogeneous Catalyst for Green Click Synthesis of β-Hydroxy-1,2,3-triazoles in Water

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