2O 2 electrogeneration at a CoS 2-based air-diffusion cathode for the electrochemical degradation of organic pollutants]]>

摘要

AbstractThis work reports, for the first time, the manufacture and use of an air-diffusion cathode containing CoS2nanoparticles to enhance the H2O2electrogeneration. Hydrothermal synthesis allowed the formation of crystalline CoS2with pyrite structure, either unsupported or supported on carbon nanotubes. Both kinds of catalysts were characterized by X-ray diffraction and FE-SEM combined with energy dispersive X-ray analysis. The use of carbon nanotubes as support led to a remarkable enhancement of the CoS2stability, as deduced from cyclic voltammetry analysis. The electrochemical activity of the CoS2-based materials towards the oxygen reduction reaction (ORR) in acidic medium was examined by potentiodynamic techniques using a rotating disk electrode. Both catalysts showed activity towards the ORR, being predominant the two-electron pathway to form H2O2as main product. A novel CoS2-on-carbon nanotubes catalyzed air-diffusion cathode, as well as an uncatalyzed one made for comparison, was manufactured to electrogenerate H2O2under galvanostatic conditions in an undivided two-electrode cell. A concentration of 56.9mM was found with the former cathode at 100mAcm?2, much >32.0mM found with the uncatalyzed cathode. This informs about the high performance of the CoS2nanoparticles to promote the two-electron ORR. Finally, the tr