Nitrogen-doped carbon xerogels as novel cathode electrocatalysts for oxygen reduction reaction in direct borohydride fuel cells

As a novel catalyst for oxygen reduction reaction (ORR), nitrogen-doped carbon xerogel was prepared via a sol-gel followed by the subsequent pyrolysis in ammonia atmosphere and post-treatment process. The resultant catalysts were characterized by BrunauereEmmetteTeller (BET), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis and electrochemical measurements. The role of metal in the catalyst was studied by comparing catalytic activities of the catalysts with and without post-treatment. Results show that the catalyst with nitrogen doped on the surface possesses an amorphous microstructure. The catalysts with and without post-treatment showed almost the same ORR electrocatalytic activities, which clearly demonstrated the negligible influence of metal removal on ORR performance. The catalyst with post-treatment displayed comparable ORR activity to that of Pt/C in alkaline medium as well as superior stability. A maximum power density of 115 mW cm(-2) at 40 degrees C was achieved on the single cell with the as-prepared catalyst as cathode, demonstrating its application as promising alternative for Pt-based electrocatalysts in direct borohydride fuel cells. (C) 2016 Elsevier Ltd. All rights reserved