RuO₂ Nanorods as an Electrocatalyst for Proton Exchange Membrane Water Electrolysis

A custom-built PEM electrolyzer cell was assembled using 6" stainless-steel ConFlat flanges which were fitted with a RuO₂ nanorod-decorated, mixed metal oxide (MMO) ribbon mesh anode catalyst. The current density-voltage characteristics were measured for the RuO₂ nanorod electrocatalyst while under constant water feed operation. The electrocatalytic behavior was investigated by making a series of physical modifications to the anode catalyst material. These experiments showed an improved activity due to the RuO₂ nanorod electrocatalyst, resulting in a corresponding decrease in the electrochemical overpotential. These overpotentials were identified by collecting experimental data from various electrolyzer cell configurations, resulting in an improved understanding of the enhanced catalytic behavior. The micro-to-nano surface structure of the anode electrocatalyst layer is a critical factor determining the overall operation of the PEM electrolyzer. The improvement was determined to be due to the lowering of the potential barrier to electron escape in an electric field generated in the vicinity of a nanorod.