Stable and methanol tolerant Pt/TiOx-C electrocatalysts for the oxygen reduction reaction

Various Pt/TiOx-C catalysts are synthesized by changing the temperature of synthesis of TiOx from 500 to 1000 degrees C. The carbon support is a commercial multi-wall carbon nanotubes. The synthesis temperature of the TiOx affects the structure and morphology of the support generating different types of suboxides, ranging from TiO2 anatase, TiO2 rutile, Ti3O, and Ti3O5. The catalysts are characterized by means of BET, EDX, XRD, and ICP-MS analyses. The obtained catalysts display a Pt loading of 13.6-19.2 wt.%, with a Pt/Ti atomic ratio of 0.177-0.194. The catalysts are electrochemically characterized by CV, CO stripping, and LSV. The presence of Ti3O5 suboxide positively improves the performance of the catalyst with respect to the oxygen reduction reaction, and enhances the catalyst stability under potential cycling, with an increase of the electrochemical active surface area (ECSA) compared to the commercial Pt/Vulcan catalyst. After stability test for 4000 cycles in range of 0.06-1.26 V vs RHE the ECSA that resulted was equal to 22.73 m(2) g(Pt)(-1). Moreover, the catalyst is highly methanol tolerant. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.