Pt–Pd bimetallic nanoparticles on MWCNTs: catalyst for hydrogen peroxide electrosynthesis

Bimetallic nanoparticles of Pt–Pd were deposited by the microemulsion method on a multiwall carbon nanotube (MWCNTs) to obtain a Pt–Pd/MWCNTs for electrocatalytic reduction of O₂ to H₂O₂. The activity and selectivity of the catalyst was determined qualitatively by the rotating disk electrode method in acidic medium. The catalyst was spray-coated onto a reticulated vitreous carbon substrate and quantitatively was tested in bulk electrolysis for 20 min under potentiostatic conditions (0.5 V vs Ag/AgCl) in a 0.5 M H₂SO₄ electrolyte using dissolved O₂. The bulk electrolysis experiments show that the Pt–Pd/MWCNTs catalyst is more efficient for H₂O₂ electrogeneration than a MWCNTs catalyst. Nitrobenzene degradation by electrogenerated H₂O₂ alone and Electro-Fenton process were also tested. Our results show that both processes decompose nitrobenzene, but the Electro-Fenton process does it more efficiently. The prepared nanoparticulated catalyst shows a great potential in environmental applications.