Thiol- and alkyne-functionalized copper nanoparticles as electrocatalysts for bisphenol A (BPA) oxidation

Copper nanoparticles (CuHT, CuPET, and CuPA) were prepared by chemical reduction of copper(II) nitrate trihydrate with functionalized by thiol and alkyne molecules. The average core diameter of these Cu nanoparticles were 2.6 ± 1.1 nm for CuHT, 2.9 ± 1.2 nm for CuPET, and 2.7 ± 1.2 nm for CuPA nanoparticles, respectively. UV-Vis measurements exhibited exponential decay profiles for all the Cu nanoparticles, typical scattering features for nanoparticles. FTIR measurements showed that the Cu cores were functionalized by these organic molecules with the breaking of the terminal -S-H and C-H groups. 1HNMR measurements also confirmed the formation of Cu nanoparticles with the existence of resonance proton peaks of aromatic ring, methylene, and methyl. X-ray photoelectron measurements showed that the copper metal centers were mostly in the zerovalent state. Electrochemical measurements were performed with cyclic voltammetry under different scan rates and varied pH values. These Cu nanoparticles all exhibited enhanced electrocatalytic activity towards the bisphenol A oxidation as compared with blank experiments. These Cu nanoparticle-modified electrodes all showed good stability and repeatability, with the detection limits estimated at the level of 10−8 M. The different catalytic capacities among these Cu nanoparticles were mainly related with the influence of peripheral organic ligands.