TaOx-capped Pt nanoparticles as active and durable electrocatalysts for oxygen reduction

Here we demonstrate the formation of unique structure of TaOx-capped Pt nanoparticles on a Pt/TaOx/GC electrocatalyst, where at first tantalum oxide (TaOx) and next Pt nanoparticles were electrodeposited on the glassy carbon (GC) substrate, for an oxygen reduction reaction. The surface characterizations show that the nanoparticles of TaOx deposit homogeneously on the GC surface, forming a thin layer and surprisingly, the Pt nanoparticles do not exactly deposit on the top layer of the TaOx, i.e., Ta2O5 but inside their framework and consequently a unique assembly of the TaOx-capped Pt particles is fabricated. The analyses using XPS spectra indicate electronic interactions of TaOx with the GC, as well as with the Pt nanoparticles. The electrochemical measurements conducted by cyclic voltammetry and rotating ring-disk electrode voltammetry reveal that the novel electrocatalyst possesses an enhanced activity for an oxygen reduction reaction, without any loss of performance even after 250 000 cycles (1111 h) of a durability test. The plausible reasons for the remarkable activity and durability of this electrocatalyst are proposed.