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 (Co 3 O 4, NiFe alloy, NiFe LDH, and Pt) for oxygen and hydrogen evolution reactions in the KOH electrolyte at different temperatures (20∼80 °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.