The synthesis of 3D graphene/Au composites via γ-ray irradiation and their use for catalytic reduction of 4-nitrophenol

Abstract

Graphene oxide (GO) and gold ions (Au3+) can be simultaneously reduced and self-assembled into a three-dimensional (3D) graphene/Au composite (GA/Au) porous structure at room temperature via one-step γ-ray irradiation. The microstructure of GA/Au composites were observed under different magnifications and the pores were observed to be uniform 3D porous structure. In addition, Au nanoparticles were homogeneously attached to graphene sheets and had a typical diameter of 6 nm. These GA/Au composites were analyzed and characterized by x-ray diffraction analysis, x-ray photoelectron spectroscopy, and thermal gravity analysis. Due to synergistic catalysis between graphene and Au nanoparticles, GA/Au composites catalyzed 4-nitrophenol with excellent catalytic performance, even at concentrations up to 6.48 × 10−3 M. When the concentration of 4-nitrophenol was 2.16 × 10−3 M and 4.22 × 10−3 M, the first-order kinetic constants were 2.00 and 1.43 min−1, respectively.

Integration of Nitrogen-Doped Graphene Oxide Dots with Au Nanoparticles for Enhanced Electrocatalytic Hydrogen Evolution

“…To estimate the efficiency of the catalytic reduction process, the catalytic efficiency was calculated using the ratio of the molar mass of 4-nitrophenol ( M ) to the molar mass of the catalyst ( m ) with reaction time in minutes ( T )­ The calculated catalytic efficiency of AuNPs without and with the presence of NGODs correspond to 0.065 and 0.263 min –1 (Figure d), respectively. The apparent rate constant of the fabricated nanocatalyst is compared with recent reports, i.e., Pt–Rh (0.209 min –1 ), RGO/Ni (0.015 min –1 ), Au–Pt Nanorods (9.3 × 10 –3 s –1 ), Au/PMMA (≈7.5 × 10 –3 s –1 ), AuNPs@microgels (3.69 × 10 –3 s –1 ), and more, − respectively (Figure e).…”

“…In addition to observing a superior catalytic behavior of AuNPs-NGODs for HER, our next goal was to study its environmental remediation applications. This application of the catalysts is widely investigated by many research groups, including ours. − Thus, the capacity of removing highly toxic organic pollutants (e.g., 4-nitrophenol) and organic dyes (e.g., methylene blue) (in the presence of NaBH 4 ) was evaluated through the abovementioned model reactions.…”

“…(b) AuNPs, (c) NGODs-AuNPs, and (d) the kinetics of AuNPs. AuNPs-NGODs catalytic reaction and (e) comparison of catalytic performance (rate constant ( K app (1/min)) and catalytic efficiencies) with various metal@carbon-based catalysts. − …”

Progress in Research on the Preparation of Graphene-Based Aerogels Using γ-ray Irradiation Technology

“…Building on these successful techniques, the same research team (as mentioned in reference [27]) employed identical preparation methods to simultaneously reduce and self-assemble GO and gold ions (Au 3+ ) in an ethanol/water solution. This innovative approach yielded a 3D graphene aerogel/gold (GA/Au) composite with an impressive high C/O ratio.…”

In situ growth of Ag nanoparticles on the surface of MXene by γ-ray irradiation to fabricate EVA composite: the improvement of flame retardancy, smoke suppression, and mechanical properties

“…Nanoparticle preparation via irradiation has been explored in various fields. In previous research [19], graphene oxide (GO) and gold ions (Au 3+ ) underwent step γ-ray irradiation at room temperature to form a three-dimensional (3D) graphene/gold composite (GA/Au) porous structure. Thanks to synergistic catalysis between graphene and gold nanoparticles, the graphene/gold composite exhibited excellent catalytic performance in catalyzing 4-nitrophenol, even at high concentrations.…”