Highly efficient and stable catalysts based on bimetallic Au(at)Ag nanoparticles decorated clay poly (glycidylmethacrylate)

Title : Highly efficient and stable catalysts based on bimetallic Au(at)Ag nanoparticles decorated clay poly (glycidylmethacrylate)

Abstract:

Nanostructured chelatant nanocomposites are emerged as promising platforms for homogeneous immobilization and stabilization of (bi)metallic nanoparticles. In this contribution, we report the preparation, characterization and catalytic applications of a new type of hybrid nanocatalysts based on gold and gold@silver mono? and bimetallic nanoparticles on polymer grafted?clay. Montmorillonite (MMT) clay was successively surfacegrafted with 3?(trimethoxysilyl)propyl methacrylate (ϒ?MAPS) and poly(glycidyl methacrylate) (PGMA) chains. The polymerization was conducted under UV?irradiation to ensure the fastgrowth of PGMA. The epoxy groups of MMT@PGMA have been readily converted into carboxylic acid and amino groups using H2SO4/KMnO4 and ethylene diamine, respectively.

Finally, Au and Au?Ag nanoparticles have been synthesized through the in situ and hydrideassisted reduction of gold or silver followed by gold ions immobilized on amino or acid carboxylic?functionalized PGMA@MMT, respectively. The hybrid nanocomposites have been characterized after each synthesis step using a combination of complementary methods (TGA, TEM, XRD, FT?IR, XPS) providing information about chemical composition, structure, and morphology of particular interest, the TEM results indicated that Au and Ag?Au NPs with a spherical shape and narrow size distribution were homogeneously and densely dispersed at the surface of chelatant nanocomposites. The so?designed Ag?Au nanoparticles decorated MMT@PGMA ternary nanocomposites have shown noticeably enhanced catalytic activity than the monometallic AuNPs in the chemical reduction of nitrophenol (p?NP) and pesticide (pemdimethalin, PDM) pollutants in the presence of sodium borohydride with high recyclability for consecutive 5 runs. The UV?monitoring of the reduction reactions indicated that pseudo?first?order kinetics associated with a rate constant of 2.10?2 s−1 and 2.8 10?2 s?1 towards p?NP 1.2 10?3 s−1 and 4.3 10?3 s?1 towards PDM using MMT@PGMA?NH2@Au and MT@PGMACOOH@Ag?Au, respectively

Further progress aims at enhancing the catalytic performances of Au NPs?PGMA?MMT nanocomposite catalyst for the treatment of contaminated waste water via a hybrid process combining heterogeneous catalysis and membrane separation.

Biography:

Samia Mahouche-Chergui obtained her Master degree in Inorganic Chemistry at Paris Sud University in 2006, and then her PhD in Surface-Interface Chemistry at Paris Diderot-P7 University in 2009. She worked then as a Lecturer/Researcher (ATER) in the same research Group developing a combination of diazonium compounds and click chemistry for the preparation of carbon hybrid materials. After postdoctoral research with Pr. Y. Grohens at the Bretagne Sud University from 2010 to 2012, she joined the East Paris Institute of Chemistry and Materials Science at the University Paris-Est Créteil as an assistant professor. Her research is currently focused on the development of sp2 carbon and clay based-functional hybrid nanostructures for applications including nanofillers, electrochemical sensors, and heterogeneous nanocatalysts.