Anchoring ultrafine Pt electrocatalysts on TiO2-C via photochemical strategy to enhance the stability and efficiency for oxygen reduction reaction
The activity and stability of Pt electrocatalysts are crucial issues for energy conversion systems involving oxygen reduction reaction (ORR). In this work, the ultrafine Pt nanoparticles were in situ reduced by the photogenerated electrons on TiO 2 surface so that most of them selectively anchored around the TiO 2 nanocrystals. The presence of well-dispersed TiO 2 on carbon surface strengthened the metal-support interaction, giving rise to the improved ORR catalytic activity with ∼49 mV positive shift of half-wave potential as compared to commercial 20 wt% Pt/C. More importantly, the Pt/TiO 2 -C catalysts exhibited a more durable performance after 10,000 cycles in terms of the decrease in electrochemical surface area (0.8%) and mass activity (0.9%), much lower than those of Pt/C (10.2% and 33.3%). The high-temperature durability test also revealed a much higher retention of ORR activity. The results demonstrated that anchoring Pt on well-dispersed TiO 2 -decorated carbon would be an effective strategy to enhance the ORR performance by strong metal-support interaction, which facilitated the electron transfer during catalytic reactions as well as prevented Pt aggregation during durability test.
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