Facile synthesis of Pd@graphene nanocomposites with enhanced catalytic activity towards Suzuki coupling reaction

Mujeeb Khan,Wolfgang Tremel,Hajo Frerichs,Abdulrahman Al–Warthan,Syed Farooq Adil,Mufsir Kuniyil,Mohammad Shahidul Islam,Mohammed Rafiq H Siddiqui,Mohammed Rafi Shaik,Muhammad Ashraf,Massih Ahmad Sarif,Joselito P Labis,Muhammad Nawaz Tahir

doi:10.1038/s41598-020-68124-w

Abstract

A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented. The HRG surfaces are tailored with amine groups using 1-aminopyrene (1-AP) as functionalizing molecules. The aromatic rings of 1-AP sit on the basal planes of HRG through π–π interactions, leaving amino groups outwards (similar like self-assembled monolayer on 2D substrates). The amino groups provide the chemically specific binding sites to the Pd nucleation which subsequently grow into nanoparticles. HRG@Pd nanocomposite demonstrated both uniform distribution of Pd nanoparticles on HRG surface as well as excellent physical stability and dispersibility. The surface functionalization was confirmed using, ultraviolet–visible (UV–Vis), Fourier transform infra-red and Raman spectroscopy. The size and distribution of Pd nanoparticles on the HRG and crystallinity were confirmed using high-resolution transmission electron microscopy and powder X-ray diffraction and X-ray photoelectron spectroscopy. The catalytic efficiency of highly reduced graphene oxide-pyrene-palladium nanocomposite (HRG-Py-Pd) is tested towards the Suzuki coupling reactions of various aryl halides. The kinetics of the catalytic reaction (Suzuki coupling) using HRG-Py-Pd nanocomposite was monitored using gas chromatography (GC).

Highlights

A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented
Based on our previous experience to synthesize layered transition metal chalcogenides and inorganic nanomaterials based nanocomposites employing Hard Soft Acid Base (HSAB) concept, we demonstrate a novel methodology to synthesize highly reduced graphene oxide-pyrene-palladium nanocomposite (HRG-Py-Pd) nanocomposites using 1-aminopyrene (1-AP) to tailor the HRG surfaces. 1-aminopyrene (1-AP) as stabilizer for this purpose, plays a dual role; (i) the basal plane of 1-AP tailor the surface of HRG through strong π–π interactions, and (ii) the amino groups, to provide a homogeneous matrices for the nucleation and growth of Pd nanoparticles
We demonstrate an approach to noncovalently functionalize the surface of graphene with polycyclic aromatic hydrocarbons (PAHs) with dual function

Summary

Introduction

A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented. This led to the better control on size and dispersion of Pd nanoparticles on the surface of the HRG leading to enhanced catalytic activity i.e. 100% coupled product within 5 min of (Iodobenzene precursor) reaction time.

Results

Conclusion