(Invited) Temperature Dependence of Electrochemical Gas-Phase Nucleation

Abstract

Classical nucleation theory (CNT) suggests that the rate of electrochemical nucleation of a gas phase, and the structure of the nuclei, are complex functions of numerous temperature-dependent system properties, including the dissolved gas diffusivity, saturation concentration, and the surface tension of the liquid-gas interface. For example, the diffusion coefficient of dissolved gases increases with temperature, whereas the surface tension of the gas/water interface decreases. Very few studies of the temperature dependence of gas phase nucleation have been reported. In this report, we describe electrochemical measurements of the nucleation of H2 and N2 nanobubbles as a function of temperature (20-75 oC). The nucleation rates of single bubble nuclei were determined using the galvanostatic technique of induction time (tind). A total of 560 measurements of tind were performed and the effect of temperature on the pre-exponential factor (Jo), activation energy (EA), nucleus contact angle (θ), and the number of molecules (n) in the nuclei were determined.