Three-Dimensional Carbon Monolith Coated by Nano-TiO2 for Anode Enhancement in Microbial Fuel Cells

A three-dimensional (3D) anode is essential for high-performance microbial fuel cells (MFCs). In this study, 3D porous carbon monoliths from a wax gourd (WGCM) were obtained by freeze-drying and carbonization. Nano-TiO2 was further coated onto the surface of WGCM to obtain a nano-TiO2/WGCM anode. The WGCM anode enhanced the maximum power density of MFCs by 167.9% compared with the carbon felt anode, while nano-TiO2/WGCM anode additionally increased the value by 45.8% to achieve 1396.2 mW/m2. WGCM enhancement was due to the 3D porous structure, the good conductivity and the surface hydrophilicity, which enhanced electroactive biofilm formation and anodic electron transfer. In addition, nano-TiO2 modification enhanced the enrichment of Acinetobacter, an electricigen, by 31.0% on the anode to further improve the power production. The results demonstrated that the nano-TiO2/WGCM was an effective anode for power enhancement in MFCs.