Enhancement of Electricity Generation in Single Chamber Microbial Fuel Cell Using Binuclear-Cobalt-Phthalocyanine and Cerium Oxide Co-Supported on Ordered Mesoporous Carbon as Cathode Catalyst

Abstract

High cost and limited natural reserves of precious metals as oxygen reduction reduction (ORR) catalysts have hindered the practical application of microbial fuel cells (MFCs). Herein, the cost-effective catalysts were synthesized by co-doping binuclear-cobalt-phthalocyanine (Bi-CoPc) and cerium oxide (CeO2) on ordered mesoporous carbon (OMC). The catalysts Bi-CoPc/x%CeO2/OMC (x = 3, 6 and 12) with different CeO2 loading were physically characterized by Nitrogen physisorption, X-ray Diffraction, Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy, and chemically characterized by Rotary Disk Electrode analysis. The relationship between the CeO2 content and ORR activity was investigated. The optimum CeO2 loading in the Bi-CoPc/6%CeO2/OMC catalyst provided the highest Ce3+ content that are favorable for the chemisorbed oxygen. Bi-CoPc/6%CeO2/OMC led to an increased half wave potential and limiting current density and to the further decreased over-potential. It also displayed a higher electron transfer number in comparison with Bi-CoPc/3%CeO2/OMC and Bi-CoPc/12%CeO2/OMC. The electrochemical results were closely related with the voltage generation obtained in single chamber MFC (SCMFCs) with air cathode. Bi-CoPc/6%CeO2/OMC-based SCMFC generated the highest power density of 486 ± 6 mW/m2 and achieved chemical oxygen demand removal of 79.3 ± 1.5%. The voltage generation for Bi-CoPc/6%CeO2/OMC decreased only by 3.7% after 1300 h of operation, indicating its good stability in MFCs large scale application.