A self-driven fuel cell to recycle (NH4)2SO4 fertilizer and energy from desulfurization solution

[Display omitted] •A self-driven fuel cell using waste as fuel.•To recycle energy and commercially valuable (NH4)2SO4 fertilizer from the (NH4)2SO3 desulfurization solution.•Electrooxidation mechanisms and dynamic parameters of sulfite and sulfate.•A lab-scale fuel cell is fabricated and simulated successfully.•The fuel cell can achieve a maximum discharge current density of 57.80 mA cm−2. This paper reports an (NH4)2SO3/air fuel cell to recover energy and commercially valuable (NH4)2SO4 fertilizer from the ammonium method desulfurization solution. The desulfurization solution and air are applied as the fuel and electron acceptor, respectively. The electrooxidation mechanisms and dynamic parameters of sulfite and sulfate on the homemade PtPd2.75/C catalyst are investigated particularly, which are verified by electron spin resonance spectrum detection. A laboratory-scale fuel cell is fabricated and simulated successfully, which contains three chambers. In this work, the highest open cell voltage of the fuel cell is 0.82 V. The fuel cell can achieve a maximum discharge current density of 57.80 mA cm−2. The highest power density is 4.78 mW cm−2 at 27.78 mA cm−2. For the actual desulfurization solution, the fuel cell can achieve a stable discharge, about 25 mA cm−2 at 0 V. This electrochemical approach offers a new way of recycling energy and matter from environmental pollutants.