Vemuri Bhuvan, Chilkoor Govinda, Dhungana Pramod, Islam Jamil, Baride Aravind, Koratkar Nikhil, Ajayan Pulickel M, Rahman Muhammad M, Hoefelmeyer James D, Gadhamshetty Venkataramana
Department of Civil and Environmental Engineering, South Dakota Mines, 501 E Saint Joseph Blvd., Rapid City, South Dakota 57701, United States.
BuGReMeDEE Consortium, South Dakota Mines, Rapid City, South Dakota 57701, United States.
ACS Omega. 2022 Apr 1;7(14):11777-11787. doi: 10.1021/acsomega.1c06950. eCollection 2022 Apr 12.
Operating microbial fuel cells (MFCs) under extreme pH conditions offers a substantial benefit. Acidic conditions suppress the growth of undesirable methanogens and increase redox potential for oxygen reduction reactions (ORRs), and alkaline conditions increase the electrocatalytic activity. However, operating any fuel cells, including MFCs, is difficult under such extreme pH conditions. Here, we demonstrate a pH-universal ORR ink based on hollow nanospheres of manganese oxide (h-MnO) anchored with multiwalled carbon nanotubes (MWCNTs) on planar and porous forms of carbon electrodes in MFCs (pH = 3-11). Nanospheres of h-MnO (diameter ∼ 31 nm, shell thickness ∼ 7 nm) on a glassy carbon electrode yielded a highly reproducible ORR activity at pH 3 and 10, based on rotating disk electrode (RDE) tests. A phenomenal ORR performance and long-term stability (∼106 days) of the ink were also observed with four different porous cathodes (carbon cloth, carbon nanofoam paper, reticulated vitreous carbon, and graphite felt) in MFCs. The ink reduced the charge transfer resistance ( ) to the ORR by 100-fold and 45-fold under the alkaline and acidic conditions, respectively. The current study promotes ORR activity and subsequently the MFC operations under a wide range of pH conditions, including acidic and basic conditions.
在极端pH条件下运行微生物燃料电池（MFC）具有显著优势。酸性条件可抑制不良产甲烷菌的生长，并提高氧还原反应（ORR）的氧化还原电位，而碱性条件则可增加电催化活性。然而，在如此极端的pH条件下运行任何燃料电池（包括MFC）都很困难。在此，我们展示了一种基于氧化锰空心纳米球（h-MnO）的pH通用型ORR墨水，该纳米球与多壁碳纳米管（MWCNT）锚定在MFC（pH = 3-11）中平面和多孔形式的碳电极上。基于旋转圆盘电极（RDE）测试，玻碳电极上的h-MnO纳米球（直径约31 nm，壳厚度约7 nm）在pH 3和10时产生了高度可重复的ORR活性。在MFC中使用四种不同的多孔阴极（碳布、碳纳米泡沫纸、网状玻璃碳和石墨毡）时，也观察到了该墨水出色的ORR性能和长期稳定性（约106天）。在碱性和酸性条件下，该墨水分别将ORR的电荷转移电阻（ ）降低了100倍和45倍。当前的研究促进了ORR活性，并随后促进了在包括酸性和碱性条件在内的广泛pH条件下的MFC运行。
