The behavior of surface nanobubbles on different substrates in electrochemistry.

• Electrocatalytic generation of nanobubble on different surfaces is investigated. • Dynamic equilibrium model of nanobubble is used to explain the influence of structure. • The concave substrate restricts the flow of water and gas molecules. In the gas evolution reaction, surface nanobubbles generally nucleate heterogeneously and grow on the electrode. It is important to understand the relationship between the evolution of nanobubbles and the structure of the electrode surface. In this work, we used molecular dynamics simulation to study the effect of different surface structures on the nucleation and growth of nanobubbles. The simulation shows that the current in the induction stage is proportional to the conversion frequency. The reaction rate in the nucleation and growth stages increases with the increase of the conversion frequency. During the stable stage, the reaction rate is higher on the plane than on the concave surface, independent of the conversion frequency. The gas influx at the contact line in the dynamic equilibrium model of nanobubbles on the electrode surface is reconsidered. The gas flux into the nanobubbles at the concave surface during the stable stage is smaller and the contact angle is smaller compared to the plane. The concave substrate restricts the flow of water molecules to the electrode surface's contact line. [ABSTRACT FROM AUTHOR]