Effect of nitrogen doping on graphite cathode for hydrogen peroxide production and power generation in MFC

Abstract

Microbial fuel cell is a sustainable and renewable technology which commonly uses graphite as cathode for hydrogen peroxide production. One of the limitations of using graphite cathode is the slow kinetics of oxygen reduction reaction. Nitrogen doping has been demonstrated to be an efficient approach to regulate the electronic as well as surface characteristics of graphite cathode. Therefore, in this study nitrogen doping of graphite cathode was performed to determine the feasibility of H2O2 production and energy generation in a dual chamber MFC. An integrated approach of quantum chemical calculation in combination with experimental investigation was used. Quantum chemical calculations confirmed the production of H2O2 with the lowest Gibb's free energy of −63 kcal/mol. For validation, ammonia treatment of graphite cathode was performed. The XPS analysis of doped cathode revealed the presence of Graphitic-N functionalization with overall N1s content of 2.96%. Cyclic voltammetric analysis of nitrogen doped cathode further confirmed the production of H2O2 at the peak current value of −4.0 mA and on-set potential of −0.55 V. Following CV analysis, hydrogen peroxide production experiments were performed in a dual chamber MFC. Maximum of 175 mg/L of H2O2 was obtained with simultaneous power generation of 47.61 W/m3, indicating the synergetic effect of nitrogen doped cathode. Thus, from the findings of quantum chemical evaluation and experimental investigation, it is concluded that nitrogen doping of graphite cathode is an efficient approach to improve the performance of MFC in terms of H2O2 production and power generation.