Design Principles for Nanobubble Regulation on Electrocatalytic Interfaces

Gas-evolving reactions, such as water splitting, are often hindered by persistent nanobubbles that block active sites, increase overpotential, and compromise reaction sustainability. Understanding nanobubble nucleation and growth is therefore essential, yet experimental characterization at the atomic scale is limited by spatiotemporal resolution. Herein, we employ molecular dynamics to probe nanobubble seeding at hydrophilic-hydrophobic heterogeneous interfaces. Using pyramidal arrays as model systems, we show that hydrophilic transport channels synergize with discretized hydrophobic domains to regulate nanobubble type, controlling site coverage and sustaining reactant delivery and product evacuation. By tuning the spatial distribution of hydrophobic domains to about three atomic spacings, optimized architectures achieve up to 18.4-fold higher steady-state currents and 9.5-fold higher current densities. This design principle is further validated using closed-loop heterogeneity, establishing an atomistically informed framework for nanobubble-resistant electrocatalytic interfaces with improved efficiency and stability.