4 Catalyst Materials for Oxygen Reduction Reaction
139
Fig. 4.37 a SEM image of 14 nm MnO x nanoparticles deposited on GC substrate, b SEM image of
14 nm MnO x nanoparticles deposited on pGC substrate, c SEM image of MnOx nanoparticles after
500 °C heat treatment, d Polarization curve of oxygen reduction of MnO/GC (1), MnO/pGC (2),
Mn 3 O 4 /pGC (3), GC (4), pGC (5) and Pt/C (6) in O 2 saturated 0.1 M KOH solution, with a rotation
speed of 1600 rpm and a scan rate of 20 mV s −1 , e Tafel curve of kinetic current of MnO/pGC
、Mn 3 O 4 /pGC and Pt/C, f Koutecky–Levich curve of Mn 3 O 4 /pGC and Pt/C, g Comparison of
specific activity of Mn 3 O 4 /pGC and Pt/C [182]. Reprinted with permission. [182] Copyright (2012)
American Chemical Society
In addition to MnO x having ORR activity, some other transition metal oxides,
such as Co 3 O 4 , Fe 3 O 4 , and MnCo 2 O 4 also have ORR activity. Liang et al. [158]
prepared Co 3 O 4 nanoparticles on graphene and nitrogen-doped graphene by a twostep method: firstly synthesize Co 3 O 4 on a graphene oxide sheet in a liquid phase,
then crystallize Co 3 O 4 at 150 °C and reduce graphite oxide. Nitrogen-doped graphene
can be obtained by adding NH 4 OH during the preparation process. In 0.1 M KOH
solution, Co 3 O 4 /rmGO showed good ORR activity, and its on-set potential reached
139
Fig. 4.37 a SEM image of 14 nm MnO x nanoparticles deposited on GC substrate, b SEM image of
14 nm MnO x nanoparticles deposited on pGC substrate, c SEM image of MnOx nanoparticles after
500 °C heat treatment, d Polarization curve of oxygen reduction of MnO/GC (1), MnO/pGC (2),
Mn 3 O 4 /pGC (3), GC (4), pGC (5) and Pt/C (6) in O 2 saturated 0.1 M KOH solution, with a rotation
speed of 1600 rpm and a scan rate of 20 mV s −1 , e Tafel curve of kinetic current of MnO/pGC
、Mn 3 O 4 /pGC and Pt/C, f Koutecky–Levich curve of Mn 3 O 4 /pGC and Pt/C, g Comparison of
specific activity of Mn 3 O 4 /pGC and Pt/C [182]. Reprinted with permission. [182] Copyright (2012)
American Chemical Society
In addition to MnO x having ORR activity, some other transition metal oxides,
such as Co 3 O 4 , Fe 3 O 4 , and MnCo 2 O 4 also have ORR activity. Liang et al. [158]
prepared Co 3 O 4 nanoparticles on graphene and nitrogen-doped graphene by a twostep method: firstly synthesize Co 3 O 4 on a graphene oxide sheet in a liquid phase,
then crystallize Co 3 O 4 at 150 °C and reduce graphite oxide. Nitrogen-doped graphene
can be obtained by adding NH 4 OH during the preparation process. In 0.1 M KOH
solution, Co 3 O 4 /rmGO showed good ORR activity, and its on-set potential reached