“…Various materials and strategies have been utilized to improve MFC anode properties, including metal and non-metal materials with/without modification. (Rosenbaum et al, 2007;Rinaldi et al, 2008;Ghasemi et al, 2013) Carbon anodes [especially materials with high porosity and large surface area, such as carbon cloth (Yuan et al, 2010), carbon fiber brush (Logan et al, 2007;Wang et al, 2011;Wei et al, 2011), PPyCNTs (Zou et al, 2008), CNT/PANI (Nourbakhsh et al, 2017), graphene (Xie et al, 2012;Wang H. et al, 2013)] are widely used in MFCs due to their excellent stability and biocompatibility. However, 3D porous electrodes recently reported had either large (>500 µm) (Xie et al, 2011;Yong et al, 2012) or small (<10 µm) (He et al, 2012) pore sizes that could hardly be tuned.…”