Weakened hydrophobic interactions enhance bubble release in electrocatalytic water-splitting

In scaling up electrocatalytic water-splitting processes, a key challenge is the inherent sluggishness resulting from bubble adhering to electrode and associated interfacial interactions at electrode-electrolyte interface. Therefore, we address this issue by modifying microenvironment at electrode-electrolyte interface, where we developed superaerophobic CoP (a representative electrocatalyst) that effectively mitigated the bubble-related problem. To elucidate underlying mechanisms of bubble release process, we systematic investigated the interaction forces between different CoP surfaces and bubbles using direct force measurements coupled with theoretical calculation. The van der Waals (VDW) and electric double layer (EDL) forces were found to be always repulsive regardless of changes in the microenvironment, and the attractive hydrophobic (HB) interaction dominated the behavior of gas bubbles (attachment or detachment) at the electrode surface during water-splitting. Enhanced superaerophobicity of our CoP stems from weakened HB attraction between the electrode and bubbles, leading to faster bubble release and facilitated interfacial mass transfer. Our finding improves the fundamental understanding of bubble dynamics in gas evolution process and provides a strategy for optimizing the performance of electrocatalysts. • A superaerophobic electrode is developed by surface treatment of CoP electrocatalysts. • Notable change of overpotential is achieved by regulating bubble-electrode interactions. • The reduction in bubble adhesion is attributed to weakened hydrophobic force. • Simple surface treatment of electrocatalysts can be applied to other materials for gas evolution.