3 The Measurements of the Oxygen Reduction Reaction
67
of 5 mV.s
−1 . The potential range is set to 0.05 V–1.1 V relative to the reversible
hydrogen electrode. The onset potential is determined by the potential of the underpotential hydrogen evolution of the electrode (see next section). The terminal potential is dependent on the initial potential of the oxygen reduction on the electrode.
The starting potential of a typical catalyst is around 1 V. If the initial potential of the
electrode oxygen reduction is positive, the terminal potential can be increased.
Correction of the oxygen reduction curve solution resistance. The solution resistance has a great influence on the objectivity of the oxygen reduction curve test. If
the solution resistance is 10 and the measured current is 1 mA at 0.9 V versus
RHE, then the oxygen reduction curve has a 10 mV shift. Although the amount
of movement is small, it will calculate the oxygen reduction activity. Have a great
impact. Our study found that the mass activity of the commercial Pt/C catalyst after
calibration can be increased by about 30%. As can be seen from Fig. 3.17, the change
in mass activity values before and after solution resistance correction at 0.9 V versus
RHE.
Based on the above measurement conditions, we determined the oxygen reduction curves of commercial Pt/C catalysts and our laboratory-made catalysts (Co@Pt)
(Fig. 3.18). The mass activity of the commercial Pt/C catalyst at 0.9 V was
124 mA.mg
−1
Pt , and the mass activity of the Co@Pt catalyst was mA.mg
−1
Pt .
3.5 Analysis of Electrochemical Reduction Curve
of Oxygen
3.5.1 Overview of Electrochemical Reduction Curves
of Oxygen
Figure 3.19 shows the oxygen reduction curve sweeped out using the rotating
ring disk electrode. The curve consists of an electrochemical polarization region,
a concentration polarization region, and a concentration polarization and electrochemical polarization mixing control region, respectively. Electrochemical polarization refers to the phenomenon of electrode polarization caused by the slow reaction
of the electrode and the reaction speed of the electrode lags behind the mass transfer
rate of the solution. This region is mainly used to analyze the dynamic principle of
the working electrode, and to solve the electrode overpotential, exchange current
density, etc. Kinetic parameters. Concentration polarization refers to the electrode
reaction process, and the diffusion rate of liquid phase mass transfer lags behind the
electrode reaction rate, thereby generating electrode polarization. From the concentration polarization region, we can get the limiting current and investigate the factors
related to the test conditions through the limiting current.
For concentrated polarization regions, if the cathode electrode reacts to.
O + en- → R
(3.44)
67
of 5 mV.s
−1 . The potential range is set to 0.05 V–1.1 V relative to the reversible
hydrogen electrode. The onset potential is determined by the potential of the underpotential hydrogen evolution of the electrode (see next section). The terminal potential is dependent on the initial potential of the oxygen reduction on the electrode.
The starting potential of a typical catalyst is around 1 V. If the initial potential of the
electrode oxygen reduction is positive, the terminal potential can be increased.
Correction of the oxygen reduction curve solution resistance. The solution resistance has a great influence on the objectivity of the oxygen reduction curve test. If
the solution resistance is 10 and the measured current is 1 mA at 0.9 V versus
RHE, then the oxygen reduction curve has a 10 mV shift. Although the amount
of movement is small, it will calculate the oxygen reduction activity. Have a great
impact. Our study found that the mass activity of the commercial Pt/C catalyst after
calibration can be increased by about 30%. As can be seen from Fig. 3.17, the change
in mass activity values before and after solution resistance correction at 0.9 V versus
RHE.
Based on the above measurement conditions, we determined the oxygen reduction curves of commercial Pt/C catalysts and our laboratory-made catalysts (Co@Pt)
(Fig. 3.18). The mass activity of the commercial Pt/C catalyst at 0.9 V was
124 mA.mg
−1
Pt , and the mass activity of the Co@Pt catalyst was mA.mg
−1
Pt .
3.5 Analysis of Electrochemical Reduction Curve
of Oxygen
3.5.1 Overview of Electrochemical Reduction Curves
of Oxygen
Figure 3.19 shows the oxygen reduction curve sweeped out using the rotating
ring disk electrode. The curve consists of an electrochemical polarization region,
a concentration polarization region, and a concentration polarization and electrochemical polarization mixing control region, respectively. Electrochemical polarization refers to the phenomenon of electrode polarization caused by the slow reaction
of the electrode and the reaction speed of the electrode lags behind the mass transfer
rate of the solution. This region is mainly used to analyze the dynamic principle of
the working electrode, and to solve the electrode overpotential, exchange current
density, etc. Kinetic parameters. Concentration polarization refers to the electrode
reaction process, and the diffusion rate of liquid phase mass transfer lags behind the
electrode reaction rate, thereby generating electrode polarization. From the concentration polarization region, we can get the limiting current and investigate the factors
related to the test conditions through the limiting current.
For concentrated polarization regions, if the cathode electrode reacts to.
O + en- → R
(3.44)