High-Density Polyethylene Waste-Derived Carbon as a Low-Cost Cathode Catalyst in Microbial Fuel Cell

Possibility of pyrolyzing high-density polyethylene (HDPE) waste and activating the HDPE-derived carbon (HDC) to be utilized as an oxygen reduction reaction (ORR) catalyst in microbial fuel cell (MFC) was explored. The Fourier transform infra-red spectrum of synthesized HDC indicated the presence of key surface functional groups that aid in catalyzing ORR, while the X-ray diffractogram indicated carbonization of HDC that enhanced electrical conductivity. Cyclic voltammogram and electrochemical impedance spectroscopy of HDC demonstrated an ORR peak current density of - 2.46 mA cm(-2), which was found to be comparable with commercial activated carbon (AC, - 2.71 mA cm(-2)). The MFC with HDC as cathode catalyst (MFC-HDC) rendered a power density (115 mW m(-2)) that was only 25% lower than the MFC with commercial AC as a catalyst (MFC-AC). Organic matter removal efficiency of MFC-HDC was comparable to MFC-AC. Thus, the low-cost HDC electrocatalyst (0.025 $ g(-1)) exhibited catalytic performance comparable with AC (12 $ g(-1)) and difference between the performance of the two MFCs with HDC and AC as catalyst can be attributed to the lower specific surface area (232 m(2) g(-1)) of the HDC catalyst as compared to AC (1200 m(2) g(-1)). Thus, for future applications, the specific surface area of HDC catalyst need to be improved to make it competitive with commercial AC. [GRAPHICS] .

Automated summary

The study explored the possibility of using carbon derived from HDPE waste as an ORR catalyst in MFC. The HDC catalyst showed comparable performance to commercial activated carbon but further improvement is needed due to its lower specific surface area.