Preparation and characterization of carbon-titania nanocomposite-supported Pd3Co alloy nanoparticles for oxygen...

A TiO2-modified carbon (C-TiO2) has been employed as a catalyst support of Pd3Co alloy for electroduction of oxygen. Due to the strong interaction between highly dispersed TiO2 and Pd3Co alloy, the C-TiO2 support was shown to be effective for a fine dispersion of Pd3Co alloys. The degree of sintering of Pd3Co on C-TiO2 could largely decrease during heat-treatment for reduction compared to that on unmodified carbon support (C). In oxygen reduction reaction (ORR), the reduced catalysts (Pd3Co/C-X and Pd3Co/C-TiO2-X; X represents reduction temperature) showed higher catalytic performance than their as-prepared catalysts. The catalytic activities of Pd3Co/C-TiO2-X were largely enhanced compared to those of Pd3Co/C-X. The ORR activity was measured to be the highest on Pd3Co/C-TiO2-300, which was 9 times enhanced activity (at 0.85 V) relative to the best-performed catalyst supported on carbon (Pd3Co/C-400). A positive role of TiO2 for the metal dispersion, the retardation of metal growth during heat-treatment, and the modification of electronic structure of Pd3Co was responsible for the enhanced ORR performance on Pd3Co/C-TiO2-X.