| Summary: | 碩士 === 國立清華大學 === 材料科學工程學系 === 99 === The relatively poor oxygen reduction activity in neutral pH condition and high cost of Pt prohibit the microbial fuel cell for commercial application. This thesis studied the oxygen reduction activity in neutral pH for pyrolyzed-vitamin B12/C and the possibility of using pyrolyzed-vitamin B12/C as microbial fuel cell cathode catalyst.
The microbial fuel cell cathode catalysts were synthesized by the following procedure. First, vitamin B12 was mixed with carbon black (XC-72), and then sintered this mixture under nitrogen environment. The best heat treatment condition of pyrolyzed-vitamin B12/C was at 700oC. We compared the oxygen reduction activity in neutral pH of pyrolyzed-vitamin B12 with the commercial Pt/C and the most popular non-noble catalyst (pyrolyzed-CoTMPP/C) by rotating ring disk electrode. In oxygen saturated neutral buffer solution, pyrolyzed-vitamin B12/C showed the best oxygen reduction activity among the three catalysts. In order to know clearly the oxygen reduction reaction mechanism, we compared the oxygen reduction activity of these three catalysts in acidic solution. For investigating the heat treatment effect, XRD, Raman, XANES, EXAFS and TEM were measured to understand the structure and electron configuration of pyrolyzed-vitamin B12
Finally, we used pyrolyzed-vitamin B12/C as microbial fuel cell cathode catalyst. The polarization curve obtained from measuring the output current and output voltage under different external resistance shows that three power density of pyrolyzed-vitamin B12 based microbial fuel cell was 50% better than the commercial Pt/C based microbial fuel cell.
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