Electrochemically co-deposited MnO2–polypyrrole hybrid cathode for efficient hydrogen peroxide reduction in alkaline media: Experimental and interfacial insights

Hydrogen peroxide fuel cells are promising energy-conversion systems owing to their high theoretical cell voltage and simple architecture. However, efficient and low-cost cathodes for the hydrogen peroxide reduction reaction (HPRR) remain challenging. Here, a MnO 2 -polypyrrole (PPy) hybrid cathode was electrochemically co-deposited onto fluorine-doped tin oxide (FTO) and evaluated in alkaline media. Structural and morphological analyses confirmed a homogeneous, predominantly poorly crystalline hybrid film with MnO 2 particles incorporated into the PPy matrix. Compared with pristine MnO 2 , the hybrid showed enhanced HPRR activity, lower charge-transfer resistance, and higher electrical conductivity (0.368 vs. 0.254 S cm −1 ). The cathodic current increased linearly with H 2 O 2 concentration (R 2 = 0.9677), while impedance and chronoamperometric measurements indicated improved charge transfer and sustained activity. DFT and atoms-in-molecules analyses provided further insight into interactions among MnO 2 , PPy, and ClO 4 − . These results highlight MnO 2 -PPy as a promising cathode for alkaline HPRR.