石墨烯氧化物气凝胶修饰金属阳极促进微生物燃料电池的产电性能

Graphene oxide aerogel modified 3D stainless steel brush/Ni-foam as high-performance microbial fuel cell anode materials

微生物燃料电池(microbial fuel cell,MFC)阳极的比表面积、生物相容性以及导电性被认为是影响微生物燃料电池产电性能的关键因素。三维金属阳极因其导电性强、比表面积较二维电极材料大等优点可用来取代碳基电极。为了提高微生物燃料电池的产电性能,本研究选用2种具有三维结构的不锈钢刷(SSB)和泡沫镍(Ni-foam)为金属阳极基材,并将石墨烯氧化物(GO)通过一步冷冻干燥法合成石墨烯氧化物气凝胶复合金属电极(GOA-SSB/Ni-foam),将其作为阳极进行MFC的产电性能研究。结果显示:在MFC运行中,GOA-SSB和GOA-Ni-foam作为阳极,最大功率密度分别达到490和119m W·m^(-2),比未修饰SSB和Ni-foam提高8.1和5.5倍。扫描电镜(SEM)表征显示三维复合金属阳极表面附着的微生物量远高于未修饰电极,且未修饰的SSB和Ni-foam电极表面较GOA-SSB和GOA-Ni-foam电极表面腐蚀更严重,说明GOA不仅可提升阳极比表面积、生物相容性还可减缓阳极基材的腐蚀。电化学阻抗(EIS)结果表明GOA-SSB和GOA-Ni-foam阳极相比于未修饰阳极能够极大的降低传荷电阻,证实GOA修饰阳极加快了电子传递速率。另外,拉曼(Raman)表征显示Shewanella oneidensis MR-1菌可原位还原GOA,佐证了GOA修饰阳极运行后欧姆内阻降低的原因。

The conductivity,biocompatibility,and specific surface area of anode materials play an important role in the power output of a microbial fuel cell（ MFC）. Metal electrode materials with a 3D structure exhibit higher conductivity and a larger specific surface area in comparison to 2D structured materials and therefore are considered to be promising alternatives to carbon-based materials. Here,we synthesized graphene oxide modified stainless steel brushes（ GOA-SSB） and graphene oxide modified nickel foam（ GOA-Ni-foam） by a one-step freeze-drying method for use as anode materials,with an aim to improve the MFC performance. The results showed that the GOA-SSB and GOA-Ni-foam anodes achieved a higher performance with a maximum power density of 490 and 119 mW·m-（-2）,8. 1 times and 5. 5 times higher than that obtained from the unmodified anodes,respectively. Such an increase was considered to be a consequence of the enhanced electron transfer,which was reflected by an increase in the anode surface area,a decrease in the anode charge transfer resistance and corrosion,and the increase in the number of bacteria attached to the anode,as evidenced from electron impedance spectroscopy（ EIS） and scanning electron microscopy（ SEM） analysis. The Raman spectra results suggested that the GOA in the anodes can be reduced by Shewanella oneidensis MR-1,which would explain the decrease in the ohmic resistance of the inoculated anodes.