General Method for Synthesizing Effective and Durable Electrocatalysts Derived from Cellulose for Microbial Fuel Cells

Catalytically Active Carbon for Oxygen Reduction Reaction in Energy Conversion: Recent Advances and Future Perspectives

The shortage and unevenness of fossil energy sources are affecting the development and progress of human civilization. The technology of efficiently converting material resources into energy for utilization and storage is attracting the attention of researchers. Environmentally friendly biomass materials are a treasure to drive the development of new-generation energy sources. Electrochemical theory is used to efficiently convert the chemical energy of chemical substances into electrical energy. In recent years, significant progress has been made in the development of green and economical electrocatalysts for oxygen reduction reaction (ORR). Although many reviews have been reported around the application of biomass-derived catalytically active carbon (CAC) catalysts in ORR, these reviews have only selected a single/partial topic (including synthesis and preparation of catalysts from different sources, structural optimization, or performance enhancement methods based on CAC catalysts, and application of biomass-derived CACs) for discussion. There is no review that systematically addresses the latest progress in the synthesis, performance enhancement, and applications related to biomass-derived CAC-based oxygen reduction electrocatalysts synchronously. This review fills the gap by providing a timely and comprehensive review and summary from the following sections: the exposition of the basic catalytic principles of ORR, the summary of the chemical composition and structural properties of various types of biomass, the analysis of traditional and the latest popular biomass-derived CAC synthesis methods and optimization strategies, and the summary of the practical applications of biomass-derived CAC-based oxidative reduction electrocatalysts. This review provides a comprehensive summary of the latest advances to provide research directions and design ideas for the development of catalyst synthesis/optimization and contributes to the industrialization of biomass-derived CAC electrocatalysis and electric energy storage.

Iron/cobalt-decorated nitrogen-rich 3D layer-stacked porous biochar as high-performance oxygen reduction air-cathode catalyst in microbial fuel cell

Developing low-cost and high-efficiency oxygen reduction reaction (ORR) catalysts is crucial to the commercial application of microbial fuel cell (MFC). Herein, Fe/Co-decorated nitrogen-rich three-dimensional (3D) layer-stacked porous biochar (Fe/Co-NC-x) have been synthesized from silk gel through secondary carbonization of activated carbons which firstly adsorbed metal ions. The multilayer porous structure of Fe/Co-NC-3 contributes to construction of high specific surface area (576 m² g^-1), large pore volume (1.27 cm³ g^-1) and many defect structure (I_D/I_G = 1.004). As expected, with Fe/Co synergistic effect, Fe/Co-NC-3 exhibits excellent ORR performance through 4e^- pathway with good methanol resistance. In addition, the performance of MFC using Fe/Co-NC-3 as air-cathode catalyst is more prominent with higher maximum power density (1059.62 ± 30.00 mW m^-2) compared to that using NC (668.19 ± 9.84 mW m^-2) and commercial Pt/C catalyst (957.33 ± 10.50 mW m^-2). Therefore, Fe/Co-NC-3 should be a prospective catalyst in the practical application of fuel cells and other energy devices.