Palladium nanoparticles loaded over sheet-like N-doped graphene oxide: investigation of its catalytic potential in Suzuki coupling, in reduction of nitroarenes and in photodegradation of methyl orange

Abstract

The discovery of nanoparticles with varied size, shape and composition has stretched the limits of nanotechnology in almost any field. One of the important areas of interest is the use of nanoparticles in heterogeneous catalysis, whereby it offers an advantage by providing large surface area. Our present work focussed on the development of a graphene-based nanocatalyst (Pd@NGO) as an efficient tool to study various organic transformations. The prepared mesoporous catalyst was characterised by X-ray diffraction (PXRD), thermogravimetric analysis (TGA), field emission-scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET), high resolution transmission electron microscopy (HR-TEM) and Fourier transformer infrared spectroscopy (FT-IR), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). TEM images showed the light grey sheets of N-GO on which Pd(0) nanoparticles were immobilised. BET analysis confirmed the mesoporous texture of the designed nanocatalyst by giving the surface area of 12.933 m² g⁻¹ with a pore volume and average pore diameter of 0.020685 cm³ g⁻¹ and 6.39 nm, respectively. Also, FTIR data affirmed the presence of a characteristic C–N peak near 1271 cm⁻¹ showing successful doping of nitrogen over graphene oxide. The XPS data revealed the presence of various elements like carbon (C 1s), nitrogen (N 1s), oxygen (O 1s) and Pd 3d. The prepared nanocatalyst was explored in Suzuki coupling reaction under green conditions, reduction of nitro compounds and the photodegradation of methyl orange with a degradation efficiency of 98.77%. The photodegradation of dyes is viewed as a potential method for the treatment of industrial wastewater due to its low cost, ecologically acceptable procedure, and lack of secondary contamination. Through direct photodegradation or a degradation process involving sensitization, this approach exhibits the light-enhanced creation of charge carriers and reactive radicals that non-selectively break down a variety of organic dyes into water, CO₂, and other organic molecules. Moreover, Pd@NGO shows excellent stability and can be used multiple times, and hence possesses efficient reusability.