Bioenergy production from bioelectrochemical cells with a platinum catalyst-free cathode

Abstract

Wastewaters contain dissolved organics that require removal before discharge into the environment. Traditionally, these organic pollutants are removed by aerobic treatment, which consumes large amounts of electrical energy for aeration. However, wastewaters are increasingly being recognized as a renewable source for the production of energy. Recently, bioelectrochemical systems (BESs) have emerged as potentially inter-esting technology for the production of energy from wastewaters. The Gibbs free energy change of the overall reaction determines how the BESs needs to be operated. When Gibbs free energy change of the overall reac-tion is negative, electrical energy can be produced, and the BES is operated as a microbial fuel cell (MFC). Conversely, when the Gibbs free energy change of the overall reaction is positive, electrical energy needs to be invested, and the BES is operated as a microbial electrolysis cell (MEC). The BESs performance, however, is mainly limited by the cathode performance and high ohmic resistance of these systems. Improving cathode performance is therefore critical for increasing BESs performance by changes in system architecture that re-duce internal resistance, such as by reducing electrode spacing and increasing solution conductivity. However, the most critical factor in the development of new cathodes for BESs is to use inexpensive materials for reducing the capital costs and enhancement of BESs performance. Therefore, this study was conducted to develop the new cathode materials for conquest of the BESs limitations toward practical implementation. First, continuous electricity generation using non-precious metal catalysts were conducted in MFCs. Iron phthalocyanine (FePc) and cobalt tetramethoxyphyenylporphyrin (CoTMPP) were used as cathode catalysts because they have been known as an excellent materials for oxygen reduction reaction in fuel cells. It could be concluded that FePc catalyst was an outstanding performance as an alterna...