SC-IrO2NR-carbon hybrid: A catalyst with high electrochemical stability for oxygen reduction

The enhanced electrochemical stability of the synthesized hybrid catalyst has been demonstrated by the introduction of the synergistic effect between carbon powder additive and the prepared catalyst. Single crystal IrO₂ nanorod (SC-IrO₂NR) catalyst was prepared by a sol-gel method. The structure and performance of the catalyst sample were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), rotating disk electrode (RDE) and cyclic voltammetry (CV) measurements. XRD patterns and TEM images indicate that the catalyst sample has a rutile IrO₂ single crystal nanorod structure. The onset potential for oxygen reduction reaction (ORR) of the SC-IrO₂NR-carbon hybrid catalyst specimen is 0.75 V (vs. RHE) in RDE measurement. CV and RDE test results show that the SC-IrO₂NR-carbon hybrid catalyst has a better electrochemical stability in comparison with the commercial Pt/C catalyst, with attenuation ratios of 17.67% and 44.60% for the SC-IrO₂NR-carbon hybrid catalyst and the commercial Pt/C catalyst after 1500 cycles, respectively. Therefore, in terms of stability, the SC-IrO₂NR-carbon hybrid catalyst has a promising potential in the application of the proton exchange membrane fuel cell.