Nanoscale conductive niobium oxides made through low temperature phase transformation for electrocatalyst support

Journal Article · Wed Jan 01 00:00:00 EST 2014 · RSC Advances

DOI:https://doi.org/10.1039/c3ra47091a· OSTI ID:1211259

Huang, K; Li, YF; Yan, LT; Xing, YC

We report an effective approach to synthesize nanoscale Nb2O5 coated on carbon nanotubes (CNTs) and transform it at low temperatures to the conductive form of NbO2. The latter, when used as a Pt electrocatalyst support, shows significant enhancement in catalyst activity and durability in the oxygen reduction reaction (ORR). Direct phase transformation of Nb2O5 to NbO2 often requires temperatures above 1000 degrees C. Here we show that this can be achieved at a much lower temperature (e.g. 700 degrees C) if the niobium oxide is first activated with carbon. Low temperature processing allows retaining nanostructures of the oxide without sintering, keeping its high surface areas needed for being a catalyst support. We further show that Pt supported on the conductive oxides on CNTs has two times higher mass activity for the ORR than on bare CNTs. The electrochemical stability of Pt was also outstanding, with only ca. 5% loss in electrochemical surface areas and insignificant reduction in half-wave potential in ORR after 5000 potential cycles.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: DE-AR0000066
• OSTI ID: 1211259
• Journal Information: RSC Advances, Vol. 4, Issue 19; ISSN 2046-2069
• Country of Publication: United States
• Language: English