Synthesis of highly stable and methanol-tolerant electrocatalyst for oxygen reduction: Co supporting on N-doped-C hybridized TiO2

Abstract The currently used carbon supported Pt or Pt alloy catalysts for cathodic oxygen reduction reaction (ORR) suffer from prohibitive cost as well as limited productivity of Pt, carbon-support corrosion, and methanol poisoning. Here we report a one-pot heat treatment for synthesis of Co supporting on N-doped-C (C-N) hybridized TiO 2 catalyst. For the first time, TiO 2 is used as the predominant content in C-based ORR catalyst. Fiber-like polyaniline (PANI) is introduced as a C-N precursor and also acts as a good template for growing TiO 2 crystals. During the following one-pot heat treatment, the metallic Co particles are in situ growing on the carbonized TiO 2 /PANI support. The influences of PANI proportion, calcination temperature, and Co incorporation on the ORR catalytic performance are systematically investigated. The optimal Co/TiO 2 /C-N catalyst shows higher stability and methanol-tolerance than commercial Pt/C or Co/C-N catalyst with comparable activity. The remarkable enhancement of stability is mainly ascribed to the following two reasons: (1) the excellent chemical stability of rutile TiO 2 ; (2) the strong interactions of “TiO 2 -PANI coupling” and “metal-support coupling”. Thus, TiO 2 /C-N appears to be a promising substitute for carbon materials when supporting metal or metal oxide catalyst for PEMFC application in terms of electrochemical stability.