Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Biosens Bioelectron. 2011 Aug 15;26(12):4728-32. doi: 10.1016/j.bios.2011.05.036. Epub 2011 May 27.
Three types of manganese dioxide, α-MnO(2), β-MnO(2), γ-MnO(2) were tested as alternative cathode catalysts for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). Prepared by solution-based methods, the MnO(2) nanomaterials were comprehensively characterized, and their electrocatalytic activities in neutral electrolyte were investigated with the supporting material of carbon nanotubes (CNTs) by cyclic voltammetry (CV). The CV results showed that all MnO(2) species could catalyze ORR in neutral NaCl solution with different catalytic activities. β-MnO(2) had the highest catalytic activity due to its intrinsic structure and better interaction with CNTs. Three MnO(2) species were further used as cathode catalysts under optimized conditions in air-cathode cubic MFCs, in which mixed culture was inoculated as biocatalysts and domestic wastewater was used as the substrate in the anode chamber. It was also found that β-MnO(2) based MFC yielded the best performance with a power density of 97.8 mWm(-2) which was 64.1% that of the Pt-based MFC, and a lower internal resistance of 165 Ω. Furthermore, the COD removal efficiency of β-MnO(2) based MFC was estimated as 84.8%, higher than that of the Pt-based MFC. This study demonstrated that using β-MnO(2) on CNT support instead of Pt could potentially improve the feasibility of scaling up air-cathode MFCs for practical applications by lowering the material cost.
三种类型的二氧化锰，α-MnO(2)、β-MnO(2)、γ-MnO(2)，被测试作为替代阴极催化剂，用于在空气阴极微生物燃料电池（MFC）中进行氧还原反应（ORR）。通过基于溶液的方法制备，对 MnO(2)纳米材料进行了全面的表征，并通过循环伏安法（CV）研究了在 CNT 支撑材料存在的情况下，MnO(2)纳米材料在中性电解质中的电催化活性。CV 结果表明，所有 MnO(2)物质都可以在中性 NaCl 溶液中催化 ORR，具有不同的催化活性。β-MnO(2)具有最高的催化活性，这归因于其内在结构和与 CNT 更好的相互作用。三种 MnO(2)物质在优化条件下，作为空气阴极立方 MFC 的阴极催化剂进一步使用，其中混合培养物作为生物催化剂接种在阳极室中，使用生活污水作为底物。研究还发现，基于β-MnO(2)的 MFC 表现出最佳性能，功率密度为 97.8 mWm(-2)，是基于 Pt 的 MFC 的 64.1%，内部电阻更低，为 165 Ω。此外，基于β-MnO(2)的 MFC 的 COD 去除效率估计为 84.8%，高于基于 Pt 的 MFC。本研究表明，使用 CNT 支撑的β-MnO(2)代替 Pt 可以通过降低材料成本，提高空气阴极 MFC 实际应用的规模化可行性。
