Asymmetric Acidic‐Alkaline Fuel Cell: Self‐Powered Hydrogen Production and Advanced Oxidation of Sulfion and Hydrazine

ABSTRACT Current technologies of water electrolysis for hydrogen production and purification of industrial wastes are effective for mitigating environmental pollution. However, they are energy‐intensive and cause indirect/direct CO ₂ emissions. Here, we report the asymmetric acid‐alkaline hydrazine‐water fuel cell (HzWFC) and sulfion‐water fuel cell (SWFC), which operate with acidic‐hydrogen evolution (HER) at the cathode and alkaline‐hydrazine/sulfion oxidation reaction (HzOR/SOR) with zero CO ₂ emission at the anode. The realization of these necessitates the development of metal organic framework‐derived V‐CoS self‐supported catalysts with optimized electronic structure, desired morphological evolution, regulated charge‐transport and optimized adsorption of HzOR/SOR intermediates. Utilizing the electrochemical neutralization energy (ENE) and favourable catalytic performance, the V‐CoS catalyst based HzWFC and SWFC generate maximum power density of 46.4 mW/cm ² (at 120 mA/cm ² ) and 15 mW/cm ² (at 61 mA/cm ² ), respectively and also, facilitates the H ₂ ‐production at current density of 240 mA/cm ² and 123 mA/cm ² at zero voltage, respectively. Realizing the ∼99% of practical Faradaic efficiency at current density of 100 mA/cm ² , the HzWFC and SWFC enable the co‐generation of electricity at a rate of 1.07 kWh/Nm ³ and 0.24 kWh/Nm ³ and H ₂ at a rate of 41.2 mL/cm ² h.