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Ammonium toxicity is a significant source of pollution from industrial civilization that is disrupting the balance of natural systems, adversely affecting soil and water quality, and causing several environmental problems that affect aquatic and human life, including the strong promotion of eutrophication and increased dissolved oxygen consumption. Thus, a cheap catalyst is required for power generation and detoxification. Herein, compost soil is employed as a novel electrocatalyst for ammonium degradation and high-power generation. Moreover, its effect on catalytic activity and material performances is systematically optimized and compared by treating it with various reducing agents, including potassium ferricyanide, ferrocyanide, and manganese dioxide. Ammonium fuel was supplied to the compost soil ammonium fuel cell (CS-AFC) at concentrations of 0.1, 0.2, and 0.3 g/mL. The overall results show that ferricyanide affords a maximum power density of 1785.20 mW/m2 at 0.2 g/mL fuel concentration. This study focuses on high-power generation for CS-AFC. CS-AFCs are sustainable for many hours without any catalyst deactivation; however, they need to be refueled at regular intervals (every 12 h). Moreover, CS-AFCs afford the best performance when ferricyanide is used as the electron acceptor at the cathode. This study proposes a cheap electrocatalyst and possible solutions to the more serious energy generation problems. This study will help in recycling ammonium-rich wastewaters as free fuel for running CS-AFC devices to yield high-power generation with reducing agents for ammonium fuel cell power applications. [ABSTRACT FROM AUTHOR]

Abstract Due to acute ammonium toxicity, it is always desirable to find a cheaper and abundant electro-catalyst other than platinum, iridium oxide, boron diamond etc with a high selectivity and negligible de-activation for its oxidation. Also ammonium is not known for electricity generation except biological nitrification process. So this paper elucidates the studies of compost as a novel electro-catalyst in a ammonium fuel cell configuration. These studies are done by varying type of electrodes & compost as well as ammonium concentration. Bi-polar cyclic voltammetry, electrochemical impedance spectroscopy, temperature dependence, cyclic stability and chrono-amperometry techniques are used to study compost. Cow dung based compost is found to show the best electro-catalytic activity. IV measurements are conducted to study power generation in tune with the electro-catalytic activity. Finally, polarization and sustainability measurements are done on a comparatively larger fuel cell to check the size scalability. The results shows that the maximum power density is 108 mW/m2 and this multifunctional device can be fueled after every 12 h for continuous operation and with negligible de-activation of electro-catalyst. These studies opens a window for doing further advanced research in compost triggered electro-catalysis to make multifunctional fuel cell devices for solving environmental and energy issues together. Graphical abstract Image 1 Highlights • Compost directly act as a abundant and cheapest electro-catalyst. • Electro-catalytic activity leads to ammonium oxidation and generation of energy. • Fuel cell is made by variation in electrodes, compost and ammonium concentration. • Individual as well as joint physio-chemical/microbial action is possible. • This work elucidates the development of multifunctional fuel cell. [ABSTRACT FROM AUTHOR]