Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: A surfactant free laser ablation approach

• Surfactant free synthesis of gold–graphene by laser ablation.
• 170 folds faster reduction for Rhodamine B than uncatalyzed reaction.
• 17,000 folds faster reduction for Methylene blue than uncatalyzed reaction.
• Doubled rate for the reduction of Rhodamine B than commercial gold nanoparticles.
• Synergism between gold nanoparticles and graphene for enhanced catalytic activity.

A facile surfactant free laser ablation mediated synthesis (LAMS) of gold–graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV–Visible spectroscopic techniques. The as-synthesized gold–graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold’s electronic relay and π–π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

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