Nitrogen-doped carbon xerogel as high active oxygen reduction catalyst for direct methanol alkaline fuel cell

Abstract

A novel catalyst based on nitrogen-doped carbon xerogel for oxygen reduction reaction (ORR) was prepared via a sol–gel process, following by the subsequent pyrolysis under ammonia atmosphere. The catalytic activity in alkaline media was optimized by tuning the metal (cobalt) ratio to the gel precursor. Sample with the optimum activity was characterized by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis and electrochemical measurements. Results show that the catalyst possesses an amorphous microstructure with nitrogen doped on the surface. The nitrogen-doped carbon xerogel displays comparable ORR activity and superior methanol tolerance than Pt/C in alkaline medium, demonstrating its promising application in direct methanol alkaline fuel cells as non-precious cathode catalyst.