Adsorption dominant catalytic activity of a carbon dots stabilized gold nanoparticles system.

Carbon dots (CDs) with abundant functional groups (-OH, -COOH, C=O) on their surface were specially designed to enhance the adsorption capacity and the catalytic activity of gold nanoparticles (AuNPs). The CDs stabilized gold nanoparticles (AuNPs-CDs) were greenly synthesized by a one-step reduction of HAuCl4 with CDs which were used as both the reductant and the stabilizer under visible light irradiation. The resulting AuNPs-CDs exhibit a high catalytic activity towards the reduction of 4-nitrophenol, with a good linear correlation of ln(C(i)/C0) versus time and a kinetic rate constant about 0.68 min(-1). Further detailed adsorption kinetics data indicated that the present adsorption system follows a predominantly second-order rate model, and the CDs capped on the surface of the AuNPs also enhanced the adsorption capacity and the catalytic activity of the AuNPs.