Rapid Characterization of Multi-Metallic Electrocatalysts for the Water Splitting Reactions Utilizing Printed Microelectrodes on a Chip

Understanding chemical composition effects is essential for creating efficient non-precious metal electrocatalysts for the water splitting reactions. Presented in this paper is a method for rapidly characterizing multi-metallic electrocatalysts utilizing printed microelectrodes on a chip. By using an ultrasonic printing technique, we demonstrate a new method to easily print microelectrodes comprising conductive wires, insulation over the wires, and a multi-metallic catalyst spot on a glass chip. We fabricated a custom test cell and electronic circuitry such that the microelectrode array can be exposed to electrolyte and voltammetry can be performed on each microelectrode independently. We also developed rapid-analysis software algorithms to quantitatively characterize each multi-metallic catalyst to obtain Tafel slopes and simulate each voltammogram using the COMSOL Multiphysics simulation software package to determine the reaction rate constant, k0eff, for each catalyst. The catalytic activity of the hydrogen evolution reaction on the Ni-Mo metallic composites in both acidic and neutral pH, and the catalytic activity of the oxygen evolution reaction on the Fe-Ni oxides in basic pH were used as model systems to demonstrate the effectiveness of this rapid-characterization technique.