Delivery of carbon dioxide to an electrode surface using a nanopipette.

We have developed a new scanning probe approach for the delivery of a gas-phase reactant to the surface of an electrocatalyst through a self-replenishing bubble located at the end of a scanning probe. This approach enables local electrocatalytic rates to be detected under very-high mass transport rates due to the small distance between the gas-phase reactant in the bubble and the electrocatalyst surface. Here we report experiments for the delivery of carbon dioxide to a gold ultramicroelectrode surface using a micron-scale nanopipette.

Scanning Bubble Electrochemical Microscopy: Mapping of Electrocatalytic Activity with Low-Solubility Reactants.

Determining electrocatalytic activity for reactions that involve reactants with limited solubility presents a significant challenge due to the reduced mass-transport to the electrocatalyst surface. This limitation is seen in important reactions such as the oxygen reduction reaction, nitrogen reduction reaction, and carbon dioxide reduction reaction. We introduce a new approach, which we call scanning bubble electrochemical microscopy, to enable the detection and high-resolution mapping of electrocatalytic activity with low-solubility reactants at high mass-transport rates.