Performance Evolution of Typical Electrocatalysts with Electrolyte Temperature during Alkaline Water Electrolysis

From Arrhenius and Eyring equations, it can be known that the temperature of an electrolyte has a significant influence on the performance of electrocatalysts during water electrolysis, but this factor is usually ignored in fundamental research. Herein, the activity, kinetics, and stability of some typical electrocatalysts (Co3O4, NiFe alloy, NiFe LDH, and Pt) for oxygen and hydrogen evolution reactions in the KOH electrolyte at different temperatures (20 similar to 80 degrees C) were investigated. Relative to the lower-temperature KOH electrolyte, the electrocatalysts in higher-temperature electrolytes showed a better water electrolysis activity and kinetics, which can be attributed to the higher conductivity at the electrolyte/electrode interface, stronger hydrophilicity on electrocatalysts, more active site formation, and lower water electrolysis resistance on electrocatalysts, but they had weaker reaction stability. In the KOH electrolyte at a higher temperature, the weaker stability of electrocatalysts mainly originated from their stronger dissolution during water electrolysis.

Automated summary

From the Arrhenius and Eyring equations, it is understood that the temperature of an electrolyte plays a crucial role in the performance of electrocatalysts during water electrolysis, which is often overlooked in fundamental research. This study investigated the activity, kinetics, and stability of several electrocatalysts (Co3O4, NiFe alloy, NiFe LDH, and Pt) for oxygen and hydrogen evolution reactions in KOH electrolyte at different temperatures (20 to 80 degrees C). The electrocatalysts exhibited better water electrolysis activity and kinetics in higher-temperature electrolytes, attributed to enhanced conductivity, increased hydrophilicity, more active site formation, and reduced electrolysis resistance. However, they displayed weaker reaction stability, primarily due to increased dissolution during water electrolysis in high-temperature KOH electrolyte.