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

초록

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 MnO2-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 MnO2 particles incorporated into the PPy matrix. Compared with pristine MnO2, 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 H2O2 concentration (R2 = 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 MnO2, PPy, and ClO4−. These results highlight MnO2-PPy as a promising cathode for alkaline HPRR.

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