Porphyrin macrocycle-stabilized gold and silver nanoparticles and their application in catalysis of hydrogen peroxide

• Amine porphyrin used as stabilizer to functionalize nanoparticles first time.
• Synthesized nanoparticles are spherical in shape.
• Nanoparticles are 3–5 nm in diameter.
• Nanoparticles act as electron mediators and good conductors.
• Nanoparticles reduce the hydrogen peroxide efficiently at lower overvoltage.

Gold and silver nanoparticles are stabilized using a cobalt aminophenyl porphyrin macrocycle by a one-step technique. The resultant nanoparticles were characterized by electronic absorption spectroscopy for plasmonic absorption peak, transmission electron microscopy and X-ray diffraction. The synthesized gold and silver nanoparticles possess a relatively homogeneous and narrow size distribution. Both gold and silver nanoparticles have an average diameter of around 5 nm with spherical shape. The porphyrin-stabilized nanoparticles show better charge transfer kinetics and act as good electron mediators. The nanoparticles-coated/modified electrodes are found to be good electrocatalysts for the reduction of hydrogen peroxide. The enhancement of catalytic activity is due to the high surface-to-volume ratio and high surface energy of the nanoparticles.

CVs of electrocatalytic reduction of H2O2 with (i) Bare GC; GC modified with (ii) CoTAPP; (iii) capped silver nanoparticles and (iv) gold nanoparticles. The electrolyte is phosphate buffer, pH 7.0. Scan rate is 50 mV/s.Figure optionsDownload as PowerPoint slide