The Effect of pH on Fuel-Cell Catalyst-Layer Inks

Abstract

Fuel-cell inks are complex colloidal mixtures of ionomer, catalyst particles, and solvent. Though there has been much work looking at the shape of ionomers in solution, most studies have not focused on understanding the interactions between the ionomer, solvent, and catalyst components. Herein, we explore how changing ionomer concentration and sonication temperature affects both dispersions and inks. Increasing temperature causes dispersion pH to decease, which then affects aggregation behavior in an ink: room temperature inks exhibit the smallest aggregate sizes of temperatures tested. Higher concentrations of ionomer are less affected by these temperature/pH relationships.