Pd nanoparticle supported reduced graphene oxide and its excellent catalytic activity for the Ullmann C-C coupling reaction in a green solvent

Abstract

An efficient and easy route to synthesize reduced graphene oxide with well dispersed palladium (Pd) nanoparticles (Pd(0)-RGO) is described. The synthesized materials were fully characterized by different techniques such as: XRD, FTIR, Raman, SEM, and TEM. An average particle size of 7.5 nm for the metal particles was confirmed by TEM analysis. Pd(0)-RGO demonstrated outstanding catalytic activity for Ullmann coupling with 97% yield and good reusability (4 cycles).

Fig. 1. XRD spectra of GO (a) and 5-Pd(0)-RGO (b) samples.

Fig. 2. Raman spectra of GO (a) and 5-Pd@RGO (b) samples.

Fig. 3. SEM image of GO, scale bar = 2 μm (a), 5-Pd(0)-RGO, scale bar = 1 μm (b) and TEM image of GO, scale bar = 200 nm (c), 5-Pd(0)-RGO, scale bar = 200 nm (d) catalyst.

Fig. 4. SEM/EDX with color mapping of 5-Pd(0)-RGO, scale bar = 1 μm catalyst.

Scheme 1. Possible mechanism for Ullmann C–C coupling reaction by Pd(0)-RGO catalyst.

Fig. 5. Recycle experiments over Pd(0)-RGO catalyst.