不同阴极对微生物燃料电池产电性能的影响比较

阴极催化性能及材料对微生物燃料电池(microbial fuel cells,MFCs)的产电特性及制造成本有很大影响。本研究选用金属铂(Pt)、活性炭作为催化剂、聚四氟乙烯(PTFE)和道康宁1-2577作为阴极的扩散层、碳布和不锈钢网作为阴极的基体材料制备得4种阴极,分别考察了相应MFC的产电性能和阴极特性。结果表明,采用传统Pt催化剂+PTFE扩散层+碳布制备成的阴极(Pt-PTC),MFC的最大输出电压为560 mV,最大功率密度为808 mW/m2,而采用活性炭+道康宁1-2577+不锈钢网制备成的阴极(AC-DCS),MFC的最大输出电压为510 mV,最大功率密度为726 mW/m2,两者的MFC产电性能极为接近。SEM结果表明,活性炭催化层表面和道康宁1-2577扩散层分别比Pt催化层及PTFE扩散层的更均匀光滑。阴极线性伏安测定结果表明,AC-DCS与Pt-PTC的电化学氧化性能较为接近。AC-DCS阴极成本仅为Pt-PTC的1/300左右,是一种低成本扩大化生产MFC阴极的新方法。

Comparison in performance of microbial fuel cells using different cathodes

The catalytic properties and materials of cathode have great effect on the power generation and the investment of microbial fuel cells (MFCs). The performance of four types of cathodes in MFCs were examined in this study. The cathodes were prepared using the platinum and activated carbon as the catalysts, polytetrafluoroethylene (PTFE) and Dow Corning 1-2577 as the diffusion layers, carbon cloth and stainless steel mesh as the basements. Results showed that the MFC using traditional cathode made by Pt catalyst + PTFE diffusion layers + carbon cloth (Pt-PTC) could obtain the maximum voltage of 560 mV and the maximum power density of 808 mW/m².The maximum voltage and the maximum power density achieved by the MFC with the cathode made by activated carbon catalyst + Dow Corning 1-2577 diffusion layers + stainless steel mesh (AC-DCS) was 510 mV and 726 mW/m², respectively. The performance of the AC-DCS cathode was comparable to that of the conventional Pt-PTC cathode. The SEM photos demonstrated that the surface of the activated carbon catalyst layer and the Dow Corning diffusion layer were more uniform and smoother than that of the Pt catalyst layer and PTFE diffusion layer, respectively. The linear sweep voltammetry (LSV) result indicated that the electrochemical oxidation of the AC-DCS cathode was similar to that of the Pt-PTC one. The construction of the AC-DCS cathode could be a promising low-cost method for the pilot-scale MFC setup, since its cost was estimated to be as low as 1/300 of that of the Pt-PTC cathode.