Effect of Morphology of ϵ‐MnO 2 on Hydrogen Peroxide Sensing

Abstract In this work, solid spherical, solid cubic and hollow cubic MnO 2 microparticles were successfully synthesized via a facile precursor conversion method. All the crystal structures were defined as rare ϵ‐phase. The ϵ‐MnO 2 was modified onto the glassy carbon electrode (GCE) to fabricate sensor platform for hydrogen peroxide (H 2 O 2 ) determination. The catalytic activity of the prepared materials was demonstrated to be in the order: hollow cubes > solid cubes > solid spheres ϵ‐MnO 2 . The higher electrochemical activity is related to the higher conductivity and more exposed highly active crystal planes instead of BET surface area, electrode active area and surface charge. Additionally, the cubic ϵ‐MnO 2 possesses greater catalytic rate constant ( K ), which is approximately an order of magnitude higher than that of spherical morphology, due to the faster electron transfer rates caused by reduced contact resistance. The proposed sensor possesses the excellent sensitivity, selectivity and stability, and is successfully applied to determine H 2 O 2 in real sample.