微生物燃料电池(MFCs)利用微生物为催化剂能同时实现污水处理和电能回收，因而具有潜在的应用价值。自从1911年发现生物电流的现象以来，MFCs的研究经历了近百年的缓慢进展和过去十五年的快速发展，在反应器构型、材料、微生物和电化学等方面，取得了大量的进展。然而，MFCs依然面临着低的功率密度和胞外电子转移(EET)等瓶颈问题。阳极作为产电菌的附着体，不仅影响着生物膜的生长，还影响电子从产电菌到阳极的传递，从而很大程度地决定MFC阳极的产电过程，进而影响整个系统的性能。因此，设计高效的三维(3D)阳极材料是提升MFCs性能和能源转化的核心之一。 为了改善碳基阳极与微生物的相互作用，本论文设计和制备多孔碳基阳极材料，通过调控碳基阳极材料的物化特性，实现了产电微生物的快速富集，进而探究材料的界面性质与组成结构对促进微生物EET的影响机制。具体研究内容如下： 采用廉价、易得的面包作为构筑碳基阳极的原材料，经过简单的焙烧，得到了多种杂原子(氮、磷和硫)掺杂的多孔碳(简称为NPS-CFs)。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附脱附仪(BET)、X射线光电子能谱仪(XPS)、X射线粉末衍射仪(XRD)、拉曼光谱仪(Raman)等技术手段对其化学组成和物理特性进行了表征，系统地探究了焙烧温度等条件对其微观结构以及化学组成的影响。结果表明，1000℃碳化得到的多孔碳(NPS-CF-1000)阳极具有最大的比表面积和丰富的孔结构、最优的杂原子掺杂量以及优异的机械强度和好的生物相容性。 为了进一步控制微生物在阳极材料内的分布，采用硬膜板法，通过自组装制备出一种新型、高效的3D有序多孔碳(简称为3D-OPC-x，x代表焙烧温度)。在此基础之上，为了进一步促进微生物和电极之间电子有序、定向、持续的传输，在3D-OPC-x结构中引入导电聚苯胺纳米结构(简称为3D-OPC-900／PANI)。通过SEM、TEM、XRD、Raman、BET、XPS以及原子力显微镜(AFM)等技术手段，研究了3D-OPC-x和3D-OPC-900／PANI阳极材料的宏观空间结构和微观孔径分布、化学组成以及和物理特性。研究表明，3D有序多孔碳和3D-OPC-900／PANI具有连续贯通的三维结构以及优异的导电性能。 研究了碳基阳极材料的表面组成和结构对MFCs启动周期、功率密度、内阻以及微生物膜伏安行为的影响。NPS-CFs、3D-OPC以及3D-OPC-900／PANI表现出快速的启动周期、高的功率。相比NPS-CFs，3D-OPC-900／PANI中导电聚苯胺(PANI)的引入对产电微生物产生了“虹吸”效应，电池在接种2-3天后就开始启动，与传统碳电极相比启动周期缩短了67％。同时，得益于合理有效的纳米结构设计，3D-OPC-900／PANI复合阳极展现出极高的体功率密度和电压，超过了商业碳布(CC)和NPS-CFs，表明3D-OPC-900／PANI能够实现对产电微生物的快速富集并展现优异的电池性能。阳极上微生物膜的伏安行为研究表明， NPS-CF-1000、3D-OPC-900和3D-OPC-900／PANI阳极的峰电流与扫描速率之间成正比，表明在这些阳极上MtrC的氧化还原反应表现为表面吸附物的氧化还原过程。然而，CC阳极表面生物膜的峰值电流与扫描速率的平方根成线性关系，表明OmcA的氧化还原反应受制于扩散控制过程。上述研究表明NPS-CFs、 3D-OPC以及3D-OPC-900／PANI电极与微生物膜具有更好的接触，从而有效地促进了微生物EET过程。使用NPS-CFs和3D-OPC-900／PANI作为微生物燃料电池阳极，实现了利用微生物对有机物去除，其中NPS-CFs阳极组装的电池中COD去除率为64.9％，而3D-OPC-900／PANI作为阳极的MFCs装置其COD去除率为68.9％。此外，同时，NPS-CFs阳极组装的电池可以成功地驱动了实际器件——电磁玩具，而3D-OPC-900／PANI作为阳极的MFCs装置首次成功地点亮了以HIT为序列的LED灯。 研究了碳基阳极的表面组成和结构对微生物菌落组成、分布以及生物相容性的影响。结果表明，碳基阳极的化学组成和理化性质影响了其表面微生物菌落结构组成的分布。相比于NPS-CFs阳极，3D-OPC和3D-OPC-900／PANI阳极更有利于导电细菌-地杆菌的富集。同时，3D-OPC-900／PANI阳极生物膜的SEM结果中有纳米导线存在，证实了微生物和电极之间直接电子传输路径。共聚焦显微镜(CLSM)的结果表明，相比于商业CC而言，NPS-CFs、3D-OPC和3D-OPC-900／PANI阳极都具有好的生物相容性。 关键词：微生物燃料电池(MFCs)；多级次结构碳；聚苯胺(PANI)；亲水性；氮、磷、硫-共掺杂；胞外电子转移(EET)

 Microbial fuel cells (MFCs) can simultaneously realize sewage treatment and electric energy recovery by using microorganism as catalyst, so it has potential application value. Since the discovery of the phenomenon of biological current in 1911, the research of MFCs has experienced a slow development in the past century and a rapid development in the past 15 years. A lot of progress has been made in reactor configuration, electrode materials, microorganism and bioelectrochemistry. However, MFCs still face some bottlenecks such as low power density and extracellular electron transfer (EET). The properties of anode, as an attachment of electroproducing bacteria, not only affects the growth of biofilm, but also the electron transfer rate from bacteria to anode, thus affecting the performance of the whole system. Therefore, the design of high efficient three dimensional (3D) anode materials is one of the core of improving the performance of MFCs and energy conversion. In order to improve the interaction between carbon-based anode and microorganism, several porous carbon-based anode materials were designed and prepared in this paper. The rapid enrichment of electroproducing microorganisms was realized, and the influence of structure, composition and interfacial property of different materials on promoting microbial EET was investigated. The specific content of the study is as follows: By using cheap and easily available bread as the raw material of electrode, the hetero-atom (nitrogen, phosphorus and sulfur) doped porous carbon foams (abbreviated as NPS-CFs) were obtained by a facile calcination method. Chemical composition and physical characteristics of the as-prepared products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), nitrogen adsorption stripping tester (BET), X-ray photoelectron spectrometer (XPS), X-ray powder diffraction (XRD), Raman spectrometer (Raman), and so on. The influence of calcination temperature on microstructure and chemical composition of calcination was also studied systematically. The results show that the porous carbon foam obtained by carbonization at 1000 ℃ (NPS-CF-1000) has the largest specific surface area, abundant pore structure, optimal doping, excellent mechanical strength and good biocompatibility. In order to efficiently control the distribution of microorganisms in the anode materials, a noval 3D ordered porous carbon (abbreviated as 3D-OPC-x) was prepared by self-assembly using a hard plate method. In addition, in order to further promote electron transfer between microorganism and electrode, conductive PANI is further introduced into 3D ordered porous carbon structure. Macroscopic spatial structure and microscopic pore size distribution, chemical composition and physical properties of 3D-OPC-X and 3D-OPC-900/PANI anode materials were studied by means of SEM, TEM, XRD, Raman, BET, XPS and atomic force microscope (AFM). The results demonstrated that 3D-OPC-X and 3D-OPC-900/PANI anode materials have ordered and interconnected 3D structure, excellent conductivity and good biocompatility. The effects of structure, chemical composition and interfacial properties of carbon-based anode materials on start-up time, power density, internal resistance of MFCs, and voltammetric behavior of microorganism were investigated. NPS-CFs, 3D-OPC and 3D-OPC-900/PANI show a fast start-up and high power density. Compared with NPS-CFs, the introduction of conductive polyaniline in 3D-OPC-900/PANI has a “siphon effect” on adhesion of electroproducing microorganisms, and the battery starts after 2-3 days of inoculation. Compared with the conventional carbon electrode, the starting period is shortened by 67%. At the same time, thanks to reasonable and effective nanostructure design, 3D-OPC-900/PANI composite anode shows excellent bulk power density and voltage, superior to commercial carbon cloth (CC) and NPS-CFs. Above results indicated that 3D-OPC-900/PANI could achieve the rapid enrichment of electroproducing microorganisms and show excellent performance. The voltammetric behavior of biofilms on anode showed that the peak current of the NPS-CF-1000, 3D-OPC-900 and 3D-OPC-900/PANI anode is proportional to the scanning rate, indicating that the redox reaction of MtrC on these anodes is subject to the surface-absorbed reactant-controlled process. However, the peak current of the biofilm on the surface of the CC anode is linear with the square root of the scanning rate, suggesting that the redox reaction of OmcA is subject to a diffusion-controlled process. Above results showed that NPS-CFs, 3D-OPC and 3D-OPC-900/PANI electrodes have better contact with microbial membrane and facilitate extracellular electron transfer between electroactive bacteria and electrode via direct electron transfer through the redox active cytochrome proteins on the bacterial outer membrane. Using NPS-CFs and 3D-OPC-900/PANI as anode, the removal of organic matter by microorganism was achieved, and COD removal rate was 64.9% for NPS-CF and 68.9% for 3D-OPC-900/PANI based MFCs, respectively. At the same time, MFCs equipped with NPS-CFs anodes could successfully drive the actual device - the electromagnetic toy, while For the first time, the HIT sequence LED lights were successfully lit with MFC equipped with 3D-OPC-900/PANI . The effects of chemical composition and interfacial properties of carbon-based anode materials on the amount of biomass, the microbial community structure and biocompatibility of the biofilmwere investigated. The results show that the chemical composition and physiochemical properties of carbon-based anode affect the microbial community structure. Compared with NPS-CFs and 3D-OPC anode, 3D-OPC-900/PANI anodes are more benefitful the enrichment of the electroactive bacteria. At the same time, SEM studies confirmed the presence of nanowires in 3D-OPC-900/PANI anode biofilms. In addition, the results of the confocal laser scanning microscopy (CLSM) show that the NPS-CFs, 3D-OPC and 3D-OPC-900/PANI anode has good biocompatibility compared with commercial carbon cloth. Key words: microbial fuel cells (MFCs), hierarchical structure carbon, polyaniline (PANI), hydrophilia, N, P, S-codoped, extracellular electron transfer (EET)