Manganese Oxide Nanorod-Decorated Mesoporous ZSM-5 Composite as a Precious-Metal-Free Electrode Catalyst for Oxygen Reduction

A precious-metal-free cathode catalyst, MnO₂ nanorod-decorated mesoporous ZSM-5 zeolite nanocomposite (MnO₂/ m-ZSM-5), has been successfully synthesized by a hydrothermal and electrostatic interaction approach for efficient electrochemical catalysis of the oxygen reduction reaction (ORR). The active MnOOH species, that is, Mn⁴⁺/Mn³⁺ redox couple and Brønsted acid sites on the mesoporous ZSM-5 matrix facilitate an approximately 4 e^- process for the catalysis of the ORR comparable to commercial 20 wt % Pt/C. Stable electrocatalytic activity with 90 % current retention after 5000 cycles, and more importantly, excellent methanol tolerance is observed. Synergetic catalytic effects between the MnO₂ nanorods and the mesoporous ZSM-5 matrix are proposed to account for the high electrochemical catalytic performance.