AFM-Quantified Adhesion Energy Describes Bubble-Mediated Mass Transport on Gas-Evolving Electrodes.

Abstract

Mass transport at three-phase interfaces is a primary bottleneck for industrial gas-evolving electrodes due to severe bubble coverage and suppressed liquid renewal. Here, we establish the interfacial work of adhesion (ΔG_ad)-quantified via spherical-tip AFM nanoindentation-as a predictive nanoscale descriptor of surface energetics under ambient conditions. ΔG_ad captures the thermodynamic competition between electrolyte wetting and gas adhesion at the solid surface, thereby governing bubble-mediated mass transport. Using model MoS₂ electrodes, we show that vertical structuring and phase engineering (V_hetero-MoS₂) significantly increase the AFM-quantified ΔG_ad. This heightened ΔG_ad strengthens the solid-electrolyte affinity, effectively suppressing gas adhesion and reducing bubble blockage. In situ Particle Image Velocimetry (PIV) and pseudopotential simulations consistently show that surfaces with higher ΔG_ad yield smaller bubbles and enhanced interfacial renewal. Accordingly, the apparent aerophobicity follows from stronger electrolyte affinity via interfacial energy competition. Using hydrogen evolution as a representative gas-evolving reaction, the V_hetero-MoS₂ electrode sustains stable hydrogen evolution at 1000 mA cm^- ². This work provides a unified energetic framework for three-phase interface engineering, establishing ΔG_ad as a quantifiable, AFM-accessible metric for the rational design of high-performance gas-evolving electrodes.