Stability and dynamic characteristics of hydrogen nanobubble

Compared to macroscopic bubbles, nanobubbles have unique physicochemical properties that make them highly promising for scientific research. Hydrogen nanobubbles (HNBs), in particular, combine hydrogen's properties with nanobubble-specific effects, offering significant applications in energy, water treatment, and medicine. This study systematically investigated the stability and dynamics of HNBs using molecular dynamics simulations. The results show that the sustained formation of HNBs requires hydrogen in water to reach supersaturation. Bubbles with diameters between 1.1 and 2.8 nm exhibit pressures ranging from 969.5 to 406.6 atm. Theoretical solubility, calculated using Henry's law based on pressure, remains valid at the nanoscale. An electrical double layer was observed at the gas-liquid interface, resulting from the reorientation of water molecules. The electrostatic force generated by the double layer counteracts the ultra-high Laplace pressure, aiding in the stability of nanobubbles. The dynamic properties, such as the diffusion coefficients of hydrogen and water, decrease as HNB size increases. The viscosity of solution containing nanobubbles of different sizes decreases by 6.64%, 8.14%, 14.16%, 19.29%, and 27.08%, respectively. These findings provide valuable insights for advancing the research and application of HNBs.