Tang Wei, Wu Xiao-Shuai, Qiao Yan, Wang Rui-Jie, Luo Xian
Institute for Clean Energy and Advanced Materials, Faculty of Materials and Energy, Southwest University Chongqing 400715 China
Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies Chongqing 400715 P. R. China.
RSC Adv. 2018 Mar 6;8(18):9597-9602. doi: 10.1039/c8ra00436f. eCollection 2018 Mar 5.
Mesoporous carbon (MC) is supposed to be a good candidate for microbial fuel cell (MFC) anodes as it possesses a large specific area for the redox reaction of the electron shuttles and should deliver high power density. However, the power generation performance of MC anodes is often un-satisfying. It seems that a large portion of the pore surface is not available for anodic redox reaction but the reason is not clear. Here, three MCs with different pore sizes and pore shapes were fabricated and used to explore the effect of the pore structure on the bioelectrocatalysis in CN32 MFCs. It is interesting that MC with 40-60 nm spheric pores (MC-III) possesses superior bio-electrocatalytic performance to the CMK-3 (MC-I with 3 nm channel like pores) and the one with 14 nm spheric pores (MC-II) although the specific surface area of MC-III is lower than MC-II and MC-I. The reason might be that the MC-III provides a more favorable pore structure than the other two MCs for flavin based redox reaction at the interface between the biofilm and the electrode. As a result, the MC-III anode delivered the highest power density at around 1700 mW m, which is 1.6 fold higher than that of the MC-I anode. A possible mechanism for the pore shape/size dependent interfacial electron transfer process has also been proposed. This work reveals that spheric mesopores with large pore width could be more favorable than the narrow channel-like pores for flavin based interfacial electron transfer in biofilm anodes, which will provide some insights for the design of the mesoporous anode in MFCs.
介孔碳（MC）被认为是微生物燃料电池（MFC）阳极的理想候选材料，因为它具有较大的比表面积，有利于电子穿梭体的氧化还原反应，并且有望提供高功率密度。然而，MC阳极的发电性能往往不尽人意。似乎很大一部分孔表面无法用于阳极氧化还原反应，但其原因尚不清楚。在此，制备了三种具有不同孔径和孔形状的MC，并用于探究孔结构对CN32 MFCs中生物电催化的影响。有趣的是，具有40 - 60 nm球形孔的MC（MC-III）具有比CMK-3（具有3 nm通道状孔的MC-I）和具有14 nm球形孔的MC（MC-II）更优异的生物电催化性能，尽管MC-III的比表面积低于MC-II和MC-I。原因可能是MC-III比其他两种MC为生物膜与电极界面处基于黄素的氧化还原反应提供了更有利的孔结构。结果，MC-III阳极在约1700 mW m处提供了最高功率密度，比MC-I阳极高1.6倍。还提出了一种孔形状/尺寸依赖性界面电子转移过程的可能机制。这项工作表明，对于生物膜阳极中基于黄素的界面电子转移，具有较大孔径的球形介孔可能比狭窄的通道状孔更有利，这将为MFCs中介孔阳极的设计提供一些见解。
