Hydrogen Bubble Nucleation in A Cylindrical Nanopore: A Coupled Model of 1D Mass Transport and Geometric Confinement
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The management of hydrogen gas generation in porous electrodes is a key challenge in water electrolysis. This work investigates bubble nucleation and mass transport in cylindrical nanopores, where geometric confinement alters diffusion pathways. A numerical model couples steady-state diffusive mass transfer with chemical and mechanical equilibrium of a surface bubble nucleating on the pore wall. Diffusion obstruction caused by a spherical-cap bubble is represented through an effective cross-sectional area, while gas–liquid equilibrium is described using Henry’s law and the Young–Laplace equation. A fixed-point iterative scheme links the dissolved hydrogen concentration field with bubble growth. Results show that bubble formation increases diffusion resistance, leading to higher local supersaturation and steeper concentration gradients. The equilibrium bubble size depends on nucleation depth due to confinement-induced variations in mass transport.
