A pH‐Universal Hollow‐Mn₃O₄/MWCNT/Nafion™ Modified Glassy Carbon Electrode for Electrochemical Oxygen Reduction

Abstract

Hollow Mn 3 O 4 nanoparticles (diameter = 31 nm, cavity diameter = 16 nm, and shell thickness = 7 nm) were attached to the surface of multiwall carbon nanotubes (MWCNT). A suspension of hollow Mn 3 O 4 /MWCNT with Nafion™ was dropcast onto a glassy carbon electrode, and the electrochemical reduction of oxygen in aqueous solution was investigated with this electrode. We assess the role of MWCNT, hollow Mn 3 O 4 , and Nafion™ in the performance of the electrode, and investigate the kinetics of the oxygen reduction reaction. The electrode exhibits outstanding performance in measures of cathodic current density and onset potential, and performed similarly well in acidic, neutral, and alkaline conditions.

Oxygen Reduction Reaction with Manganese Oxide Nanospheres in Microbial Fuel Cells

“…These nanospheres were characterized by an inner diameter of ∼20 nm, outer diameter of 30–40 nm, and shell thickness of ∼7 nm. 17 , 18 An immediate application of as-synthesized ink is its use as a noninvasive coating to promote the ORR activity of carbon electrodes in MFCs. As seen in Figure 2 , both the planar and porous forms of electrodes were amenable to the modification by the ink.…”

“…Our earlier studies demonstrated the hollow morphology of the h-Mn 3 O 4 nanospheres based on the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and TEM image analyses (Figure b). These nanospheres were characterized by an inner diameter of ∼20 nm, outer diameter of 30–40 nm, and shell thickness of ∼7 nm. , An immediate application of as-synthesized ink is its use as a noninvasive coating to promote the ORR activity of carbon electrodes in MFCs. As seen in Figure , both the planar and porous forms of electrodes were amenable to the modification by the ink.…”

“…Details on combining h-Mn 3 O 4 , MWCNT and Nafion binder for obtaining a stock solution of the ink has been described in our earlier works (ref ( 18 )) ( Figure 6 (referred to as ink or catalyst ink).…”

“… 8 − 13 The Mn x O y nanoparticles can be obtained in various shapes and sizes, as needed by the devices. 14 − 16 We present a first study that explores the ORR activity of hollow h-Mn 3 O 4 nanospheres 17 , 18 under extreme conditions in MFCs. We present a scalable route for synthesizing the ink based on nanospheres, anchor them with MWCNTs, and deposit them on diverse electrodes, including a planar glassy carbon and four porous carbon electrodes.…”

“…Earth-abundant materials, M–N–C materials, where M = earth-abundant transition metals (e.g., nickel and manganese), N = nitrogen, C = carbon, can yield viable ORR catalysts for MFC applications. Catalysts based on the Mn x O y nanoparticles have emerged as attractive choices for electrochemical devices. − The Mn x O y nanoparticles can be obtained in various shapes and sizes, as needed by the devices. − We present a first study that explores the ORR activity of hollow h-Mn 3 O 4 nanospheres , under extreme conditions in MFCs. We present a scalable route for synthesizing the ink based on nanospheres, anchor them with MWCNTs, and deposit them on diverse electrodes, including a planar glassy carbon and four porous carbon electrodes.…”