Application of Bimetallic Cathode Catalysts for Enhancing the Performance of Microbial Fuel Cell: A Review

Microbial fuel cells (MFCs) have gained considerable importance for the production of bioelectricity and other value-added products recovery along with the concomitant treatment of wastewater. However, the poor power output of MFC as a result of sluggish oxygen reduction reaction (ORR) remains one of the major setbacks of this green technology. Application of metal composite as cathode catalyst has shown tremendous potential in this regard to the augmentation of power generation through MFC. Thus, this review article pivots around the role of bimetallic catalysts in boosting the ORR and critically evaluates different metal composites employed in lab-scale as well as field-scale MFCs chiefly in terms of power generation. In this regard, bimetallic catalyst such as Cu-Sn have shown the maximum power density of 470.2 +/- 27.3 mW/m(2) and coulombic efficiency of 36.4 +/- 2.1% compared to the power density obtained by the MFC with Pt/C as cathode catalyst (465.3 +/- 27.1 mW/m(2)), which shows that bimetallic catalysts possess excellent ORR activity and are more sustainable with respect to expensive Pt based catalyst. Similarly, Cu-Zn bimetallic catalysts have shown the competence for application in both lab- and field-scale. Moreover, the effect of synthesis procedure, structural morphology, and electrochemical behavior of bimetallic catalysts has been scrutinized and summarized in this review. Therefore, this review is an attempt to fill the existing knowledge void on composite metal catalysts and would aid budding scholars in carrying out influential research work in the future.

Automated summary

Microbial fuel cells (MFCs) are important for bioelectricity production and wastewater treatment. However, the low power output of MFCs due to slow oxygen reduction reaction (ORR) is a major challenge. The application of bimetallic catalysts in MFCs has shown potential in improving power generation. This review evaluates different metal composites used in lab-scale and field-scale MFCs, focusing on power generation and ORR activity. It also discusses the synthesis, morphology, and electrochemical behavior of bimetallic catalysts.