Enabling highly effective underwater oxygen-consuming reaction at solid-liquid-air triphasic interface

Abstract Electrode surfaces with superhydrophobic and conductive properties exhibit a unique energy-mass transfer behavior in electrolytes. Therefore, the rational design of electrode surface structures, conductivity, and infiltration performance is expected to yield more efficient electrochemical reactions and solve the gas-deficit problem that hinders many underwater gas-consuming reaction systems. In this paper, hydrogenated carbon nano-onions displaying superhydrophobicity and conductivity were prepared by microwave plasma-enhanced chemical vapor deposition, which exhibited remarkable transferability and designability. The fabricated carbon nano-onions were used to modify the surfaces of various materials and structures toward their application to self-cleaning, oil-water separation, and enabling highly effective underwater oxygen-consuming reactions. Systematic analyses of the different wetting states of the superhydrophobic electrodes coated with the fabricated carbon nano-onions indicated that the different wetting states have important effects on their behaviors for underwater nucleation reactions, thus changing the efficiency of underwater oxygen-consuming reaction systems. The results reveal that designing a superhydrophobic electrode with a Wenzel-Cassie coexistent underwater wetting state, rather than a Cassie state or Wenzel state, is the key to enabling highly effective underwater oxygen-consuming reactions.