Electrochemical stability of silica-templated polyaniline-derived mesoporous N-doped carbons for the design of Pt-based oxygen reduction reaction catalysts

In order to improve the stability of carbon supported Pt-based oxygen reduction reaction catalyst a mesoporous N-doped carbon support (MPNC) was developed which shows both a higher resistance against carbon corrosion and Pt agglomeration compared to a commercial Pt catalysts supported on Vulcan XC72R. The MPNC were synthesized via a hard templating approach based on the oxidative polymerisation of aniline in the presence of SiO2 nanospheres as hard templates. Carbonization of the resulting PANI/SiO2 composite and template removal yielded MPNCs with pores imprinted in terms of size and shape by the SiO2 templates. The first part of the paper describes how the properties of the MPNCs were modified. Differences in shape, porosity, graphitization and N-doping are investigated by elemental analysis, scanning transmission electron microscopy, N-2 physisorption analysis and near edge x-ray absorption fine structure spectroscopy. The carbon structure/morphology of the different MPNCs was then correlated with their electrochemical stability during accelerated stress test cycling. The MPNCs stability was thereby addressed and compared to Vulcan XC72R by evaluating changes in the double layer capacity. Finally, the stability of a MPNC supporting Pt NPs is shown and discussed by its comparison to a commercial available Pt catalyst supported on Vulcan XC72R. (c) 2019 Elsevier Ltd. All rights reserved.