| It is one key factor for fuel cells to develop more efficient cathode catalysts. However,traditional Pt/C catalyst material is still hindered by several factors, including the highcosts of Pt-based electrocatalysts, durability of carbon supported catalysts and thecrossover of methanol from the anode to the cathode.This research use SiC particles as the basic material forming one shell/core structuralcathodiccatalyst. First, the method of acid etching was used to obtain one pre-carbonationSiC particles. Nanoporous amorphous carbons formed on the surface of SiC after acidetching. Secondly, these pre-carbination particles went through one1300oC vacuumannealing process with melamine for forming one N-doped CDC/SiC, which has one SiCcore and one N-doped CDC shell. For the improved method, N doping procedure wasperformed by one-pot vacuum annealing SiC, nickel chloride (NiCl2) and melamine at1000oC. The NiCl2decomposed into nickel (Ni) and chlorine (Cl2) at the elevatedtemperature. The decomposed Cl2extracted silicon atoms from SiC substrate andtransformed the surface carbide structure into CDC shell. Ni served as an accelerant,which primarily facilitated the incorporation of N. The structure and morphologies of thefinal obtained materials were characterized by x-ray photoelectron spectroscopic, electronenergy loss spectroscopy, Raman spectra and high resolution transmission electronmicroscopy. The electrochemical results showed that the prepared shell/core structuralN-doped CDC/SiC particles behaved as efficient cathode catalysts showed high catalyticactivity for oxygen reduction and highly resistant to methanol crossover and their stabilitywere better than Pt/C. Because the SiC core retains high thermal and morphologicalstability and the N-doped carbon shell endows it an excellent catalytic performance forORR. N-doped CDC/SiC was expected to be a good candidate as a cathode catalyst forfuel cells. |
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