Investigation on the Influence of Nafion on Cobalt Electrocatalysts in the Oxygen Evolution Reaction
Timothy Lin, Alexandra Guardado Menjivar
Department of Chemistry & Biochemistry
Faculty Supervisor: Jingjing Qiu
The catalyst layer is a crucial component in water electrolyzers, responsible for splitting water into hydrogen and oxygen gas. Anodic catalyst layers are typically stabilized on the electrode with a Nafion ionomer, which enhances catalyst adhesion and ion conductivity in the oxygen evolution reaction (OER). In an alkaline electrolyte, the earth abundant first-row transition metal catalysts are effective in the OER process. Cobalt hydroxide (Co(OH)2) and cobalt (II,III) oxide (Co3O4) are two promising electrocatalysts that are relatively abundant and known for their competitive catalytic activity. In this work, we explore the formulation recipes of Co(OH)2 and Co3O4 catalyst inks with the Nafion ionomer and apply voltametric techniques to study the influence of Nafion on cobalt catalysts. Our preliminary data indicates that excess Nafion hinders catalytic activity while increasing its stability. An ideal ionomer-catalyst ratio is determined to achieve a good balance of stability and efficiency of the catalyst. Additionally, we find that the ratio of water to alcohol in the catalyst ink solvent influences catalytic behavior, with a 75 vol% of water and 25 vol% of isopropanol forming the most active catalyst layer.