The Role of Hydrogen Adsorption Energy on Nanobubble Formation During Water Electrolysis

Electrochemical reactions with gaseous products often face the challenge of lowered efficiencies due to the formation of gas bubbles which block active sites on the electrode surface. Improving water electrolysis for the generation of hydrogen gas is especially of interest as it pertains to clean energy through the use of hydrogen fuels. Here we report the use of two complementary optical microscopy techniques to explore the formation of hydrogen nanobubbles and microbubbles on a modified ITO electrode. Two noble metals (Pt, Au) with known hydrogen adsorption energies are deposited on the ITO surface in small, microscopic features, and their catalytic activities towards water reduction are evaluated through the resulting electrochemical current and optical microscopy. Using total internal reflection fluorescence (TIRF) microscopy and reflection microscopy cohesively, we are able to observe the appearance of hydrogen nanobubbles on both the metal features and the surrounding ITO. The hydrogen adsorption energy of the selected metals is correlated to the number of nanobubbles that can be detected, with higher energies leading to an increase in nanobubbles.